Neurology — MCQs

Q: Which of the following is NOT associated with AIDS?

Hypogammaglobulinemia. **Explanation:** In AIDS, the hallmark of the disease is the progressive depletion of CD4+ T-helper cells [1], leading to profound immune dysregulation. **Why Hypogammaglobulinemia is the Correct Answer:** Patients with AIDS typically exhibit **Hypergammaglobulinemia** (specifically polyclonal gammaglobulinemia), not hypogammaglobulinemia. This occurs because of chronic, non-specific B-cell activation. Although the B-cells are increased in number and produce high levels of immunoglobulins (IgG and IgA), they are functionally defective and fail to mount an effective antibody response to new antigens or vaccines. **Analysis of Incorrect Options:** * **A. Increased p24 antibody:** In the early stages of HIV infection (seroconversion), the body produces antibodies against the p24 capsid antigen [2]. While p24 *antigen* levels rise during acute infection and late-stage AIDS, p24 *antibodies* are characteristic of the asymptomatic phase. * **C. Abnormal mitogen assay:** Since T-cell function is severely compromised, there is a decreased proliferative response to mitogens (like Phytohemagglutinin/PHA). This is a classic laboratory finding in cellular immunodeficiency. * **D. Anergy:** This refers to the lack of a delayed-type hypersensitivity (DTH) response to common recall antigens (e.g., Tuberculin/PPD). It occurs due to the profound loss of effector T-cells [1]. **High-Yield NEET-PG Pearls:** * **CD4:CD8 Ratio:** In healthy individuals, the ratio is ~2:1. In AIDS, this ratio **inverts** to <1:1 [1]. * **B-cell paradox:** AIDS is characterized by high quantitative globulins but poor qualitative function (increased risk of infections by encapsulated bacteria like *S. pneumoniae*). * **Window Period:** The time between infection and the appearance of detectable antibodies (usually 2-12 weeks). The p24 antigen is the earliest marker detectable during this phase [2].

Q: Subacute sclerosing panencephalitis (SSPE) is a complication of which viral infection?

Measles. **Explanation:** **Subacute Sclerosing Panencephalitis (SSPE)** is a rare, progressive, and fatal neurodegenerative disease caused by a persistent, aberrant infection of the central nervous system with a **mutated Measles virus**. [1] 1. **Why Measles is Correct:** SSPE occurs years (typically 5–10) after an initial measles infection, usually in children who contracted the virus before age two. [1] The underlying mechanism involves a **defective "M" (matrix) protein** of the measles virus, which prevents the virus from budding out of host cells. Instead, the virus spreads directly from cell to cell via syncytia formation, leading to widespread inflammation, demyelination, and neuronal death in both gray and white matter (hence "panencephalitis"). 2. **Why Other Options are Incorrect:** * **Rubella:** Associated with Progressive Rubella Panencephalitis (PRP), which clinically mimics SSPE but is caused by the Rubella virus. * **Mumps:** Commonly causes viral meningitis or acute encephalitis, but not a chronic sclerosing panencephalitis. * **Chickenpox (VZV):** Can cause acute cerebellar ataxia or encephalitis, and its reactivation leads to Herpes Zoster (shingles), but not SSPE. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Stages:** Characterized by behavioral changes (Stage 1), followed by pathognomonic **periodic myoclonic jerks** (Stage 2), and eventually dementia and akinetic mutism. * **EEG Finding:** Classic **periodic, high-voltage slow-wave complexes** (Radermecker complexes) synchronized with myoclonus. * **CSF Analysis:** Shows significantly **elevated anti-measles antibody titers** and oligoclonal bands (increased IgG). [2] * **Diagnosis:** Based on Dyken’s criteria. * **Prevention:** The most effective strategy is vaccination with the **MMR vaccine**. [1]

Q: What is the most common cause of death in measles?

Pneumonia. **Explanation:** **Pneumonia** is the most common cause of death associated with measles in both children and adults. Measles virus causes profound transient immunosuppression by depleting T-lymphocytes and altering cytokine responses. This predisposes patients to secondary bacterial infections (most commonly *S. pneumoniae*, *H. influenzae*, and *S. aureus*) or primary viral giant cell pneumonia (Hecht’s pneumonia) [1]. While measles is often perceived as a simple rash, respiratory complications account for nearly 60% of measles-related mortality. **Analysis of Incorrect Options:** * **Encephalitis:** While Acute Disseminated Encephalomyelitis (ADEM) and Subacute Sclerosing Panencephalitis (SSPE) are severe neurological complications with high morbidity, they occur much less frequently than respiratory complications [1]. * **Meningitis:** Measles rarely presents as isolated meningitis; neurological involvement typically manifests as encephalitis or encephalopathy. * **Dehydration:** Although diarrhea is the most common *complication* of measles overall (especially in malnourished children), it is secondary to pneumonia as a cause of death in global statistics. **NEET-PG High-Yield Pearls:** * **Most common complication:** Diarrhea. * **Most common cause of death:** Pneumonia. * **Most common CNS complication:** Acute febrile encephalitis. * **Pathognomonic sign:** Koplik spots (found opposite the lower second molars) [1]. * **Vitamin Supplementation:** Vitamin A is crucial in management as it reduces the severity of complications and mortality risk [1]. * **SSPE:** A late, fatal neurodegenerative complication occurring years after the initial infection due to a persistent mutant virus [1].

Q: Herpes zoster most commonly involves which nerve division?

Ophthalmic division of Trigeminal. **Explanation:** Herpes Zoster (Shingles) results from the reactivation of the latent Varicella-Zoster Virus (VZV) within the sensory ganglia. While the virus most frequently affects the **thoracic dermatomes** (50–60% of cases) [1], the **Trigeminal nerve (Cranial Nerve V)** is the most common cranial nerve involved. Among the three branches of the Trigeminal nerve, the **Ophthalmic division (V1)** is most frequently affected, a condition known as *Herpes Zoster Ophthalmicus*. This occurs because the virus remains latent in the trigeminal ganglion and, upon reactivation, travels preferentially along the V1 fibers to the forehead and cornea. **Analysis of Options:** * **Option B (Correct):** The Ophthalmic division (V1) is the most common site for cranial zoster. Involvement of the nasociliary branch (indicated by vesicles on the tip of the nose—**Hutchinson’s sign**) is a strong predictor of ocular complications like keratitis. * **Options C & D (Incorrect):** The Maxillary (V2) and Mandibular (V3) divisions are significantly less common sites for reactivation compared to V1. * **Option A (Incorrect):** While the Facial nerve (CN VII) can be involved (leading to **Ramsay Hunt Syndrome** or Herpes Zoster Oticus), it is less frequent than Trigeminal involvement. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common site overall:** Thoracic dermatomes (T3 to L2) [1]. 2. **Hutchinson’s Sign:** Vesicles on the side or tip of the nose; indicates high risk of corneal involvement. 3. **Ramsay Hunt Syndrome:** Triad of ipsilateral facial paralysis, ear pain, and vesicles in the auditory canal (CN VII involvement). 4. **Post-herpetic Neuralgia (PHN):** The most common complication of Herpes Zoster, defined as pain persisting >90 days after the rash heals [1]. 5. **Treatment:** Oral Acyclovir, Valacyclovir, or Famciclovir (ideally started within 72 hours) [1].

Q: What is the drug of choice for acyclovir-resistant herpes simplex virus (HSV) or varicella-zoster virus (VZV) infections?

Foscarnet. **Explanation:** The mechanism of resistance in HSV and VZV against Acyclovir most commonly involves a **mutation or deficiency in the viral enzyme Thymidine Kinase (TK)** [1]. Since Acyclovir requires TK for its initial phosphorylation to become active, TK-deficient strains are resistant to Acyclovir, Valacyclovir, and Famciclovir [1]. **1. Why Foscarnet is the Correct Answer:** Foscarnet is a pyrophosphate analog that **directly inhibits viral DNA polymerase** without requiring activation (phosphorylation) by viral Thymidine Kinase. Therefore, it remains highly effective against TK-deficient, acyclovir-resistant strains of HSV and VZV. **2. Analysis of Incorrect Options:** * **Valacyclovir (Option C) & Famciclovir (Option D):** These are prodrugs of Acyclovir and Penciclovir, respectively. Like Acyclovir, they require viral Thymidine Kinase for activation [1]. If a virus is resistant to Acyclovir due to a TK mutation, it will show cross-resistance to these drugs [1]. * **Cidofovir (Option B):** While Cidofovir also bypasses the need for viral TK (it is a nucleotide analog), it is generally considered a **second-line** alternative to Foscarnet for acyclovir-resistant HSV due to its significant nephrotoxicity and lower clinical preference in this specific scenario. **Clinical Pearls for NEET-PG:** * **Mechanism of Foscarnet:** Non-competitive inhibition of RNA and DNA polymerase (binds to the pyrophosphate binding site). * **Major Side Effect of Foscarnet:** Nephrotoxicity and electrolyte imbalances (hypocalcemia, hypomagnesemia, and hypokalemia). It can also cause genital ulcerations. * **Drug of Choice for CMV Retinitis:** Ganciclovir (Foscarnet is used if Ganciclovir resistance develops). * **Acyclovir Resistance:** Most common in immunocompromised patients (e.g., HIV/AIDS) [1], [2].

Q: What is the causative agent of SARS?

Coronavirus. **Explanation:** **Correct Answer: A. Coronavirus** Severe Acute Respiratory Syndrome (SARS) is caused by the **SARS-associated coronavirus (SARS-CoV)**. Coronaviruses are large, enveloped, positive-sense single-stranded RNA (+ssRNA) viruses characterized by club-shaped surface projections (peplomers) that create a "halo" or crown-like appearance under electron microscopy. They primarily cause respiratory and enteric diseases. The SARS outbreak (2002–2004) originated in China and is zoonotic, with the **masked palm civet** and **bats** identified as key reservoirs. **Why other options are incorrect:** * **B. Picornavirus:** This family includes small, non-enveloped RNA viruses such as Poliovirus, Rhinovirus (common cold), and Hepatitis A. While Rhinoviruses cause respiratory symptoms, they do not cause SARS. * **C. Myxovirus:** This group includes Orthomyxoviruses (Influenza) and Paramyxoviruses (Measles, Mumps, RSV). While they cause significant respiratory pathology, their genomic structure and replication cycles differ from Coronaviridae. * **D. Retrovirus:** These are RNA viruses (like HIV) that use reverse transcriptase to integrate their genetic material into the host DNA. They are not associated with acute primary respiratory syndromes like SARS. **High-Yield Clinical Pearls for NEET-PG:** * **Receptor:** SARS-CoV and SARS-CoV-2 both utilize the **ACE-2 receptor** (Angiotensin-Converting Enzyme 2) found in the lungs, heart, and kidneys to enter host cells. * **MERS-CoV:** Another highly pathogenic coronavirus (Middle East Respiratory Syndrome) uses the **DPP-4 receptor**. * **Diagnosis:** Gold standard is **RT-PCR**. * **Imaging:** Characterized by "ground-glass opacities" on HRCT chest.

Q: Which viral infection is associated with neutropenia?

All of the above. Explanation: Neutropenia (absolute neutrophil count <1500/µL) is a common hematological manifestation of various viral infections. The underlying pathophysiology typically involves direct bone marrow suppression, the production of inhibitory cytokines (like IFN-γ), or the induction of anti-neutrophil antibodies. * **Hepatitis A:** While more commonly associated with transient leukopenia, Hepatitis A can cause bone marrow suppression. In rare but severe cases, it is a known trigger for **aplastic anemia**, which presents with profound neutropenia. * **Influenza A:** Acute viral respiratory infections, particularly Influenza, frequently cause a shift in neutrophil distribution (margination) and temporary marrow suppression, leading to a decrease in circulating neutrophils during the early phase of illness. * **HIV:** Neutropenia occurs in approximately 10–50% of HIV-infected individuals [1]. It results from direct infection of marrow stromal cells, secondary opportunistic infections (like CMV), or as a side effect of antiretroviral therapy (e.g., Zidovudine) [1]. **Clinical Pearls for NEET-PG:** 1. **Most common viral cause of neutropenia:** HIV and Cytomegalovirus (CMV) are high-yield associations [2]. 2. **Post-viral Neutropenia:** Usually occurs within the first 24–48 hours of infection and is typically transient. 3. **Differential Diagnosis:** Always consider **Epstein-Barr Virus (EBV)** and **Parvovirus B19** (which specifically targets erythroid precursors but can cause pancytopenia) when evaluating a patient with viral symptoms and low blood counts [1]. 4. **Drug-induced:** In PG exams, remember that **Ganciclovir** (used for CMV) and **Zidovudine** (AZT) are classic pharmacological causes of neutropenia in viral contexts [1].

Q: What is the marker test for vertical transmission of HIV?

p24 antigen. ### Explanation **Correct Option: A. p24 antigen** In the context of vertical transmission (mother-to-child), the gold standard for diagnosing HIV in infants under 18 months is **HIV DNA PCR** or **p24 antigen assay** [2]. The underlying medical concept is the **transplacental transfer of maternal IgG antibodies**. If a mother is HIV-positive, her antibodies will be present in the infant's blood for up to 18 months, regardless of whether the infant is actually infected. Therefore, tests that detect antibodies will yield a "false positive" result [1]. To confirm infection in a neonate, we must detect the virus itself (viral load/DNA) or its structural components, such as the **p24 capsid protein**, which appear before the host mounts an antibody response [2]. **Why other options are incorrect:** * **B. Serum ELISA:** This is a screening test that detects HIV antibodies [1]. In infants, it cannot differentiate between maternal antibodies and neonatal infection. * **C & D. Western Blot / Immunoblot:** These are confirmatory tests that detect specific antibodies against HIV proteins (like gp120, gp41). Like ELISA, they remain positive in infants due to maternal IgG, making them unreliable for diagnosing vertical transmission [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Window Period:** p24 antigen is the first marker to appear after infection (usually within 1–3 weeks), making it useful for early diagnosis before seroconversion. * **Best Initial Test for Infants ( 18 months):** ELISA (4th generation tests now detect both p24 and antibodies). * **Confirmatory Test (Adults):** Western Blot (though newer algorithms favor Geenius™ HIV 1/2 supplemental assays) [1].

Neurology Indian Medical PG Practice Questions and MCQs

Question 1: Which of the following is NOT associated with AIDS?

A. Increased p 24 antibody
B. Hypogammaglobulinemia (Correct Answer)
C. Abnormal mitogen assay
D. Anergy

Explanation: **Explanation:** In AIDS, the hallmark of the disease is the progressive depletion of CD4+ T-helper cells [1], leading to profound immune dysregulation. **Why Hypogammaglobulinemia is the Correct Answer:** Patients with AIDS typically exhibit **Hypergammaglobulinemia** (specifically polyclonal gammaglobulinemia), not hypogammaglobulinemia. This occurs because of chronic, non-specific B-cell activation. Although the B-cells are increased in number and produce high levels of immunoglobulins (IgG and IgA), they are functionally defective and fail to mount an effective antibody response to new antigens or vaccines. **Analysis of Incorrect Options:** * **A. Increased p24 antibody:** In the early stages of HIV infection (seroconversion), the body produces antibodies against the p24 capsid antigen [2]. While p24 *antigen* levels rise during acute infection and late-stage AIDS, p24 *antibodies* are characteristic of the asymptomatic phase. * **C. Abnormal mitogen assay:** Since T-cell function is severely compromised, there is a decreased proliferative response to mitogens (like Phytohemagglutinin/PHA). This is a classic laboratory finding in cellular immunodeficiency. * **D. Anergy:** This refers to the lack of a delayed-type hypersensitivity (DTH) response to common recall antigens (e.g., Tuberculin/PPD). It occurs due to the profound loss of effector T-cells [1]. **High-Yield NEET-PG Pearls:** * **CD4:CD8 Ratio:** In healthy individuals, the ratio is ~2:1. In AIDS, this ratio **inverts** to <1:1 [1]. * **B-cell paradox:** AIDS is characterized by high quantitative globulins but poor qualitative function (increased risk of infections by encapsulated bacteria like *S. pneumoniae*). * **Window Period:** The time between infection and the appearance of detectable antibodies (usually 2-12 weeks). The p24 antigen is the earliest marker detectable during this phase [2].

Question 2: Subacute sclerosing panencephalitis (SSPE) is a complication of which viral infection?

A. Rubella
B. Mumps
C. Measles (Correct Answer)
D. Chickenpox

Explanation: **Explanation:** **Subacute Sclerosing Panencephalitis (SSPE)** is a rare, progressive, and fatal neurodegenerative disease caused by a persistent, aberrant infection of the central nervous system with a **mutated Measles virus**. [1] 1. **Why Measles is Correct:** SSPE occurs years (typically 5–10) after an initial measles infection, usually in children who contracted the virus before age two. [1] The underlying mechanism involves a **defective "M" (matrix) protein** of the measles virus, which prevents the virus from budding out of host cells. Instead, the virus spreads directly from cell to cell via syncytia formation, leading to widespread inflammation, demyelination, and neuronal death in both gray and white matter (hence "panencephalitis"). 2. **Why Other Options are Incorrect:** * **Rubella:** Associated with Progressive Rubella Panencephalitis (PRP), which clinically mimics SSPE but is caused by the Rubella virus. * **Mumps:** Commonly causes viral meningitis or acute encephalitis, but not a chronic sclerosing panencephalitis. * **Chickenpox (VZV):** Can cause acute cerebellar ataxia or encephalitis, and its reactivation leads to Herpes Zoster (shingles), but not SSPE. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Stages:** Characterized by behavioral changes (Stage 1), followed by pathognomonic **periodic myoclonic jerks** (Stage 2), and eventually dementia and akinetic mutism. * **EEG Finding:** Classic **periodic, high-voltage slow-wave complexes** (Radermecker complexes) synchronized with myoclonus. * **CSF Analysis:** Shows significantly **elevated anti-measles antibody titers** and oligoclonal bands (increased IgG). [2] * **Diagnosis:** Based on Dyken’s criteria. * **Prevention:** The most effective strategy is vaccination with the **MMR vaccine**. [1]

Question 3: What is the most common cause of death in measles?

A. Encephalitis
B. Meningitis
C. Dehydration
D. Pneumonia (Correct Answer)

Explanation: **Explanation:** **Pneumonia** is the most common cause of death associated with measles in both children and adults. Measles virus causes profound transient immunosuppression by depleting T-lymphocytes and altering cytokine responses. This predisposes patients to secondary bacterial infections (most commonly *S. pneumoniae*, *H. influenzae*, and *S. aureus*) or primary viral giant cell pneumonia (Hecht’s pneumonia) [1]. While measles is often perceived as a simple rash, respiratory complications account for nearly 60% of measles-related mortality. **Analysis of Incorrect Options:** * **Encephalitis:** While Acute Disseminated Encephalomyelitis (ADEM) and Subacute Sclerosing Panencephalitis (SSPE) are severe neurological complications with high morbidity, they occur much less frequently than respiratory complications [1]. * **Meningitis:** Measles rarely presents as isolated meningitis; neurological involvement typically manifests as encephalitis or encephalopathy. * **Dehydration:** Although diarrhea is the most common *complication* of measles overall (especially in malnourished children), it is secondary to pneumonia as a cause of death in global statistics. **NEET-PG High-Yield Pearls:** * **Most common complication:** Diarrhea. * **Most common cause of death:** Pneumonia. * **Most common CNS complication:** Acute febrile encephalitis. * **Pathognomonic sign:** Koplik spots (found opposite the lower second molars) [1]. * **Vitamin Supplementation:** Vitamin A is crucial in management as it reduces the severity of complications and mortality risk [1]. * **SSPE:** A late, fatal neurodegenerative complication occurring years after the initial infection due to a persistent mutant virus [1].

Question 4: Herpes zoster most commonly involves which nerve division?

A. Facial nerve
B. Ophthalmic division of Trigeminal (Correct Answer)
C. Mandibular division of Trigeminal
D. Maxillary division of Trigeminal nerve

Explanation: **Explanation:** Herpes Zoster (Shingles) results from the reactivation of the latent Varicella-Zoster Virus (VZV) within the sensory ganglia. While the virus most frequently affects the **thoracic dermatomes** (50–60% of cases) [1], the **Trigeminal nerve (Cranial Nerve V)** is the most common cranial nerve involved. Among the three branches of the Trigeminal nerve, the **Ophthalmic division (V1)** is most frequently affected, a condition known as *Herpes Zoster Ophthalmicus*. This occurs because the virus remains latent in the trigeminal ganglion and, upon reactivation, travels preferentially along the V1 fibers to the forehead and cornea. **Analysis of Options:** * **Option B (Correct):** The Ophthalmic division (V1) is the most common site for cranial zoster. Involvement of the nasociliary branch (indicated by vesicles on the tip of the nose—**Hutchinson’s sign**) is a strong predictor of ocular complications like keratitis. * **Options C & D (Incorrect):** The Maxillary (V2) and Mandibular (V3) divisions are significantly less common sites for reactivation compared to V1. * **Option A (Incorrect):** While the Facial nerve (CN VII) can be involved (leading to **Ramsay Hunt Syndrome** or Herpes Zoster Oticus), it is less frequent than Trigeminal involvement. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common site overall:** Thoracic dermatomes (T3 to L2) [1]. 2. **Hutchinson’s Sign:** Vesicles on the side or tip of the nose; indicates high risk of corneal involvement. 3. **Ramsay Hunt Syndrome:** Triad of ipsilateral facial paralysis, ear pain, and vesicles in the auditory canal (CN VII involvement). 4. **Post-herpetic Neuralgia (PHN):** The most common complication of Herpes Zoster, defined as pain persisting >90 days after the rash heals [1]. 5. **Treatment:** Oral Acyclovir, Valacyclovir, or Famciclovir (ideally started within 72 hours) [1].

Question 5: What is the drug of choice for acyclovir-resistant herpes simplex virus (HSV) or varicella-zoster virus (VZV) infections?

A. Foscarnet (Correct Answer)
B. Cidofovir
C. Valacyclovir
D. Famciclovir

Explanation: **Explanation:** The mechanism of resistance in HSV and VZV against Acyclovir most commonly involves a **mutation or deficiency in the viral enzyme Thymidine Kinase (TK)** [1]. Since Acyclovir requires TK for its initial phosphorylation to become active, TK-deficient strains are resistant to Acyclovir, Valacyclovir, and Famciclovir [1]. **1. Why Foscarnet is the Correct Answer:** Foscarnet is a pyrophosphate analog that **directly inhibits viral DNA polymerase** without requiring activation (phosphorylation) by viral Thymidine Kinase. Therefore, it remains highly effective against TK-deficient, acyclovir-resistant strains of HSV and VZV. **2. Analysis of Incorrect Options:** * **Valacyclovir (Option C) & Famciclovir (Option D):** These are prodrugs of Acyclovir and Penciclovir, respectively. Like Acyclovir, they require viral Thymidine Kinase for activation [1]. If a virus is resistant to Acyclovir due to a TK mutation, it will show cross-resistance to these drugs [1]. * **Cidofovir (Option B):** While Cidofovir also bypasses the need for viral TK (it is a nucleotide analog), it is generally considered a **second-line** alternative to Foscarnet for acyclovir-resistant HSV due to its significant nephrotoxicity and lower clinical preference in this specific scenario. **Clinical Pearls for NEET-PG:** * **Mechanism of Foscarnet:** Non-competitive inhibition of RNA and DNA polymerase (binds to the pyrophosphate binding site). * **Major Side Effect of Foscarnet:** Nephrotoxicity and electrolyte imbalances (hypocalcemia, hypomagnesemia, and hypokalemia). It can also cause genital ulcerations. * **Drug of Choice for CMV Retinitis:** Ganciclovir (Foscarnet is used if Ganciclovir resistance develops). * **Acyclovir Resistance:** Most common in immunocompromised patients (e.g., HIV/AIDS) [1], [2].

Question 6: Herpes zoster infection can lead to which of the following complications?

A. Frontal lobe infarction
B. Parietal lobe infarction
C. Temporal lobe infarction
D. Occipital neuralgia (Correct Answer)

Explanation: ### Explanation **Correct Option: D (Occipital neuralgia)** **Mechanism:** Herpes Zoster (Shingles) is caused by the reactivation of the **Varicella-Zoster Virus (VZV)** latent in the sensory ganglia [1]. While it most commonly affects thoracic dermatomes [1], it can involve the cervical spinal nerves. **Occipital neuralgia** occurs when the virus involves the **C2 and C3 nerve roots**, which give rise to the greater and lesser occipital nerves. The inflammation and subsequent nerve damage (post-herpetic neuralgia) lead to paroxysmal, lancinating pain in the posterior scalp and occipital region [1]. **Why Incorrect Options are Wrong:** * **Options A, B, and C (Lobe Infarctions):** While VZV is a known cause of **vasculopathy** (leading to stroke), it does not typically cause isolated "lobar" infarctions in a pattern specific to the frontal, parietal, or temporal lobes as a primary complication. VZV vasculopathy usually involves the **Middle Cerebral Artery (MCA)** territory or small penetrating vessels, leading to hemiplegia. However, in the context of this specific question, occipital neuralgia is a classic, direct sensory nerve complication of the infection. **High-Yield Clinical Pearls for NEET-PG:** * **Hutchinson’s Sign:** Vesicles on the tip of the nose indicate involvement of the nasociliary branch of the ophthalmic nerve (CN V1), predicting a high risk of **Herpes Zoster Ophthalmicus**. * **Ramsay Hunt Syndrome (Type II):** Reactivation in the **geniculate ganglion** (CN VII) leading to facial palsy, ear pain, and vesicles in the external auditory canal. * **Post-Herpetic Neuralgia (PHN):** Defined as pain persisting for >90 days after the rash heals [1]. First-line treatment includes **Gabapentin, Pregabalin, or Amitriptyline**. * **VZV Vasculopathy:** A unique cause of stroke in young patients or those with recent ophthalmic shingles; it results from the virus migrating along the trigeminal nerves to the cerebral arteries.

Question 7: Pneumocystis prophylaxis is indicated when the CD4 count is?

A. <200 cells/mm ³ (Correct Answer)
B. <300 cells/mm ³
C. <400 cells/mm ³
D. <500 cells/mm ³

Explanation: ### Explanation **1. Why Option A is Correct:** The risk of developing **Pneumocystis jirovecii pneumonia (PCP)**—the most common opportunistic infection in HIV patients—increases significantly as the immune system weakens. Clinical guidelines (WHO and NACO) mandate primary prophylaxis with **Trimethoprim-Sulfamethoxazole (TMP-SMX)** when the CD4 T-lymphocyte count falls below **200 cells/mm³** or if the patient has a history of oropharyngeal candidiasis (a clinical marker of advanced immunosuppression) [1]. At this threshold, the host's cell-mediated immunity is insufficient to suppress the fungus, leading to life-threatening interstitial pneumonia. **2. Why Other Options are Incorrect:** * **Options B, C, and D:** While patients with CD4 counts between 200 and 500 cells/mm³ are immunocompromised, they generally maintain enough cellular immunity to prevent PCP [1]. Initiating prophylaxis at these higher levels is not recommended as it unnecessarily increases the risk of drug toxicity (e.g., Stevens-Johnson Syndrome) and antibiotic resistance. **3. NEET-PG Clinical Pearls & High-Yield Facts:** * **Drug of Choice:** TMP-SMX (Double strength tablet once daily). * **Alternative if allergic to Sulfa:** Dapsone or Atovaquone [1]. * **Discontinuation:** Prophylaxis can be safely stopped if the CD4 count rises above **>200 cells/mm³ for at least 3–6 months** in response to ART. * **Other CD4 Thresholds for Prophylaxis:** * **<100 cells/mm³:** Prophylaxis for *Toxoplasma gondii* (using TMP-SMX). * **<50 cells/mm³:** Prophylaxis for *Mycobacterium avium complex* (MAC) using Azithromycin (though guidelines now prioritize immediate ART over MAC prophylaxis). * **Radiology Tip:** Look for "ground-glass opacities" and "perihilar infiltrates" on a chest X-ray/CT [1].

Question 8: What is the causative agent of SARS?

A. Coronavirus (Correct Answer)
B. Picornavirus
C. Myxovirus
D. Retrovirus

Explanation: **Explanation:** **Correct Answer: A. Coronavirus** Severe Acute Respiratory Syndrome (SARS) is caused by the **SARS-associated coronavirus (SARS-CoV)**. Coronaviruses are large, enveloped, positive-sense single-stranded RNA (+ssRNA) viruses characterized by club-shaped surface projections (peplomers) that create a "halo" or crown-like appearance under electron microscopy. They primarily cause respiratory and enteric diseases. The SARS outbreak (2002–2004) originated in China and is zoonotic, with the **masked palm civet** and **bats** identified as key reservoirs. **Why other options are incorrect:** * **B. Picornavirus:** This family includes small, non-enveloped RNA viruses such as Poliovirus, Rhinovirus (common cold), and Hepatitis A. While Rhinoviruses cause respiratory symptoms, they do not cause SARS. * **C. Myxovirus:** This group includes Orthomyxoviruses (Influenza) and Paramyxoviruses (Measles, Mumps, RSV). While they cause significant respiratory pathology, their genomic structure and replication cycles differ from Coronaviridae. * **D. Retrovirus:** These are RNA viruses (like HIV) that use reverse transcriptase to integrate their genetic material into the host DNA. They are not associated with acute primary respiratory syndromes like SARS. **High-Yield Clinical Pearls for NEET-PG:** * **Receptor:** SARS-CoV and SARS-CoV-2 both utilize the **ACE-2 receptor** (Angiotensin-Converting Enzyme 2) found in the lungs, heart, and kidneys to enter host cells. * **MERS-CoV:** Another highly pathogenic coronavirus (Middle East Respiratory Syndrome) uses the **DPP-4 receptor**. * **Diagnosis:** Gold standard is **RT-PCR**. * **Imaging:** Characterized by "ground-glass opacities" on HRCT chest.

Question 9: Which viral infection is associated with neutropenia?

A. Hepatitis A
B. Influenza A
C. HIV
D. All of the above (Correct Answer)

Explanation: Explanation: Neutropenia (absolute neutrophil count <1500/µL) is a common hematological manifestation of various viral infections. The underlying pathophysiology typically involves direct bone marrow suppression, the production of inhibitory cytokines (like IFN-γ), or the induction of anti-neutrophil antibodies. * **Hepatitis A:** While more commonly associated with transient leukopenia, Hepatitis A can cause bone marrow suppression. In rare but severe cases, it is a known trigger for **aplastic anemia**, which presents with profound neutropenia. * **Influenza A:** Acute viral respiratory infections, particularly Influenza, frequently cause a shift in neutrophil distribution (margination) and temporary marrow suppression, leading to a decrease in circulating neutrophils during the early phase of illness. * **HIV:** Neutropenia occurs in approximately 10–50% of HIV-infected individuals [1]. It results from direct infection of marrow stromal cells, secondary opportunistic infections (like CMV), or as a side effect of antiretroviral therapy (e.g., Zidovudine) [1]. **Clinical Pearls for NEET-PG:** 1. **Most common viral cause of neutropenia:** HIV and Cytomegalovirus (CMV) are high-yield associations [2]. 2. **Post-viral Neutropenia:** Usually occurs within the first 24–48 hours of infection and is typically transient. 3. **Differential Diagnosis:** Always consider **Epstein-Barr Virus (EBV)** and **Parvovirus B19** (which specifically targets erythroid precursors but can cause pancytopenia) when evaluating a patient with viral symptoms and low blood counts [1]. 4. **Drug-induced:** In PG exams, remember that **Ganciclovir** (used for CMV) and **Zidovudine** (AZT) are classic pharmacological causes of neutropenia in viral contexts [1].

Question 10: What is the marker test for vertical transmission of HIV?

A. p24 antigen (Correct Answer)
B. Serum ELISA
C. Western blot
D. Immunoblot

Explanation: ### Explanation **Correct Option: A. p24 antigen** In the context of vertical transmission (mother-to-child), the gold standard for diagnosing HIV in infants under 18 months is **HIV DNA PCR** or **p24 antigen assay** [2]. The underlying medical concept is the **transplacental transfer of maternal IgG antibodies**. If a mother is HIV-positive, her antibodies will be present in the infant's blood for up to 18 months, regardless of whether the infant is actually infected. Therefore, tests that detect antibodies will yield a "false positive" result [1]. To confirm infection in a neonate, we must detect the virus itself (viral load/DNA) or its structural components, such as the **p24 capsid protein**, which appear before the host mounts an antibody response [2]. **Why other options are incorrect:** * **B. Serum ELISA:** This is a screening test that detects HIV antibodies [1]. In infants, it cannot differentiate between maternal antibodies and neonatal infection. * **C & D. Western Blot / Immunoblot:** These are confirmatory tests that detect specific antibodies against HIV proteins (like gp120, gp41). Like ELISA, they remain positive in infants due to maternal IgG, making them unreliable for diagnosing vertical transmission [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Window Period:** p24 antigen is the first marker to appear after infection (usually within 1–3 weeks), making it useful for early diagnosis before seroconversion. * **Best Initial Test for Infants (<18 months):** HIV DNA PCR (more sensitive than p24) [2]. * **Standard Screening (>18 months):** ELISA (4th generation tests now detect both p24 and antibodies). * **Confirmatory Test (Adults):** Western Blot (though newer algorithms favor Geenius™ HIV 1/2 supplemental assays) [1].

Question 11: What is the chance of vertical transmission of Hepatitis B?

A. 25-30% (Correct Answer)
B. 40%
C. 60%
D. 90-95%

Explanation: **Explanation:** The risk of vertical transmission (mother-to-child) of Hepatitis B Virus (HBV) is primarily determined by the mother's serological status, specifically the presence of the **HBeAg (Hepatitis B e-antigen)**, which signifies high viral replication. 1. **Why 25-30% is correct:** In a general population of HBV-infected pregnant women (including both HBeAg-positive and HBeAg-negative mothers), the overall risk of vertical transmission without immunoprophylaxis is approximately **25-30%**. Most of these transmissions occur during the peripartum period (delivery) due to contact with maternal blood and vaginal secretions [1]. 2. **Analysis of Incorrect Options:** * **Option B (40%) & C (60%):** These figures do not correspond to standard epidemiological benchmarks for HBV transmission. * **Option D (90-95%):** This is a high-yield distractor. While 90-95% is not the *overall* transmission rate, it represents the risk of transmission if the mother is **both HBsAg and HBeAg positive**. Additionally, 90% is the risk that a neonate infected at birth will develop **chronic** Hepatitis B [1]. **Clinical Pearls for NEET-PG:** * **Timing:** Most vertical transmission occurs during **delivery** (birth canal). Transplacental (in-utero) transmission is rare (<5%). * **Prevention:** Administration of the **HBV vaccine and HBIG (Hepatitis B Immunoglobulin)** to the newborn within 12 hours of birth reduces the transmission risk by >90%. * **Antiviral Therapy:** If maternal HBV DNA is >200,000 IU/mL, Tenofovir is recommended starting at 28–32 weeks gestation to further reduce transmission risk. * **Breastfeeding:** Is **not** contraindicated in HBV-positive mothers, provided the infant receives the recommended immunoprophylaxis.

Question 12: What is the most common opportunistic fungal infection in patients with HIV?

A. Histoplasmosis
B. Candidiasis (Correct Answer)
C. Cryptosporidium
D. Cryptococcus

Explanation: **Explanation:** The correct answer is **Candidiasis**. In the context of HIV/AIDS, fungal infections are significant markers of disease progression. **Oropharyngeal Candidiasis (Thrush)** is recognized as the most common opportunistic fungal infection overall in HIV patients [1]. It typically occurs when the CD4 count falls below 200–500 cells/mm³. While it is not an AIDS-defining illness itself, its presence is a strong clinical predictor of progression to AIDS. Esophageal candidiasis, however, is considered an AIDS-defining condition [1]. **Analysis of Incorrect Options:** * **Histoplasmosis:** This is a regional fungal infection (endemic in certain river valleys). While it is a common opportunistic infection in specific geographic areas, it is not the most common globally or generally compared to Candida. * **Cryptosporidium:** This is a **protozoan** parasite, not a fungus. It causes chronic watery diarrhea in AIDS patients (CD4 <100 cells/mm³). * **Cryptococcus:** *Cryptococcus neoformans* is the most common cause of opportunistic **fungal meningitis** in HIV patients [1], but it is less frequent than mucosal Candidiasis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common opportunistic infection (overall):** *Pneumocystis jirovecii* (formerly a fungus, now classified as a yeast-like fungus; however, in many traditional classifications, Candidiasis remains the most frequent fungal manifestation). * **Most common fungal meningitis:** Cryptococcosis (diagnosed via India Ink preparation or CrAg lateral flow assay) [1]. * **CD4 Thresholds:** * Thrush: <500 cells/mm³ * Pneumocystis: <200 cells/mm³ * Cryptococcus/Histoplasmosis: <100 cells/mm³ * CMV/MAC: <50 cells/mm³

Question 13: Hecht's pneumonia is typically seen in:

A. Measles (Correct Answer)
B. Malaria
C. RSV
D. Pneumococcus

Explanation: **Explanation:** **Hecht’s Pneumonia**, also known as **Giant Cell Interstitial Pneumonia**, is a severe and often fatal complication of the **Measles virus (Rubeola)** [1]. It typically occurs in immunocompromised individuals (e.g., those with leukemia, HIV, or severe malnutrition) who are unable to mount an effective T-cell response [1]. 1. **Why Measles is Correct:** The Measles virus causes the fusion of infected epithelial cells, leading to the formation of characteristic **multinucleated giant cells** (Warthin-Finkeldey cells) containing eosinophilic intranuclear and intracytoplasmic inclusion bodies. In Hecht’s pneumonia, these giant cells infiltrate the alveolar spaces [1]. Notably, this condition can occur without the classic measles rash (exanthem) in immunocompromised patients [1]. 2. **Why Other Options are Incorrect:** * **Malaria:** Primarily causes Pulmonary Edema or ARDS due to capillary leakage and red cell sequestration, not giant cell pneumonia. * **RSV:** While a common cause of bronchiolitis and pneumonia in infants, it is characterized by syncytia formation but is not associated with the specific "Hecht’s" eponymous giant cell pathology. * **Pneumococcus:** Causes classic lobar pneumonia characterized by intra-alveolar neutrophilic exudate (Red/Grey hepatization), not interstitial giant cell changes. **High-Yield Clinical Pearls for NEET-PG:** * **Warthin-Finkeldey Cells:** Pathognomonic multinucleated giant cells found in lymphoid tissue and lungs in Measles. * **Koplik Spots:** Small white spots on the buccal mucosa; the hallmark pre-eruptive sign of Measles [1]. * **Vitamin A:** Supplementation is recommended for all children with acute measles to reduce morbidity and mortality. * **SSPE:** A late neurological complication of measles occurring years after the initial infection [1].

Question 14: A resident doctor sustained a needle stick injury while sampling blood of a patient who is HIV positive. A decision is taken to offer him post-exposure prophylaxis. Which one of the following would be the best recommendation?

A. Zidovudine + Lamivudine for 4 weeks
B. Zidovudine + Lamivudine + Nevirapine for 4 weeks
C. Zidovudine + Lamivudine + Indinavir for 4 weeks (Correct Answer)
D. Zidovudine + Stavudine + Nevirapine for 4 weeks

Explanation: **Explanation:** The management of needle stick injuries in healthcare workers involves assessing the risk of transmission and initiating **Post-Exposure Prophylaxis (PEP)** [1]. According to the standard guidelines (NACO/CDC) applicable to this scenario, the goal is to use a multi-drug regimen to prevent viral replication. **Why Option C is Correct:** In high-risk exposures (such as a needle stick from a known HIV-positive patient), an **expanded regimen** is preferred over a basic regimen [2]. This typically consists of **two Nucleoside Reverse Transcriptase Inhibitors (NRTIs)**—Zidovudine and Lamivudine—combined with a **Protease Inhibitor (PI)** like Indinavir (or Lopinavir/Ritonavir in more recent guidelines) [2]. The duration of PEP is strictly **4 weeks (28 days)**. **Analysis of Incorrect Options:** * **Option A:** This is a "basic regimen." While used for low-risk exposures, a needle stick from a known positive patient warrants the addition of a third drug for maximum efficacy [2]. * **Option B:** Nevirapine is contraindicated in PEP because of the risk of severe hepatotoxicity and Stevens-Johnson Syndrome in HIV-negative individuals receiving it for prophylaxis. * **Option D:** Combining Zidovudine and Stavudine is pharmacologically irrational as they compete for the same phosphorylation pathway (antagonistic effect). **NEET-PG High-Yield Pearls:** * **Timing:** PEP should ideally be started within **2 hours**, but can be initiated up to **72 hours** post-exposure. It is generally not recommended after 72 hours. * **Current Preferred Regimen (Updated):** While Indinavir was the classic choice, modern guidelines now prefer **Tenofovir + Lamivudine + Dolutegravir** due to better tolerability. * **Testing Schedule:** Baseline testing [1] is followed by repeat HIV testing at 6 weeks, 12 weeks, and 6 months [1].

Question 15: A subject was brought to the Casualty with a history of RTA and head injury. On examination, he was conscious. When the doctor asked questions about the incident, his answers were irrelevant to the questions, but his speech was fluent. What could be the possible site of injury?

A. Brain stem
B. Inferior frontal gyrus
C. Superior temporal gyrus (Correct Answer)
D. Pre-central gyrus

Explanation: ***Correct Answer: Superior temporal gyrus*** - The patient exhibits **fluent aphasia** (fluent speech) with severely **impaired comprehension** (irrelevant answers), which is the hallmark of **Wernicke's aphasia** [1]. - **Wernicke's area**, responsible for language comprehension, is located in the posterior aspect of the dominant hemisphere's **superior temporal gyrus** [1]. *Incorrect: Pre-central gyrus* - This area houses the primary **motor cortex**; damage typically results in contralateral **hemiparesis** or paralysis, not selective language comprehension deficits [1]. - Although cortical damage can cause speech articulation issues (**dysarthria**), it does not account for the specific fluent aphasia with catastrophic loss of understanding described. *Incorrect: Inferior frontal gyrus* - The dominant inferior frontal gyrus contains **Broca's area**, damage to which results in **non-fluent aphasia** (impaired speech production) with preserved comprehension [1]. - This presentation (fluent speech, poor comprehension) is diametrically opposite to the expected profile of **Broca's aphasia** [1]. *Incorrect: Brain stem* - Injury here often causes severe alterations in **consciousness**, cranial nerve palsies, or **dysarthria** due to involvement of motor pathways. - The brain stem is not primarily involved in complex, higher-order language functions like comprehension; pure Wernicke's aphasia is a **cortical syndrome** [1].

Question 16: A patient presents with contralateral face, arm, and leg weakness. NCCT shows intracerebral hemorrhage (ICH). What is the most likely location of the CNS bleed?

A. Pons
B. Midbrain
C. Basal ganglia (Correct Answer)
D. Medulla

Explanation: ***Basal ganglia*** - The **basal ganglia**, particularly the **putamen**, is the most common site for hypertensive intracerebral hemorrhage, which aligns perfectly with the deep parenchymal bleed seen on the provided NCCT scan. - A lesion in this location classically damages the adjacent **internal capsule**, where motor fibers for the face, arm, and leg are tightly packed, resulting in **contralateral hemiparesis**. *Midbrain* - A midbrain hemorrhage would present with distinct cranial nerve deficits, most notably **oculomotor nerve (CN III) palsy**, causing a "down and out" eye position, ptosis, and a dilated pupil. - Other characteristic signs include altered consciousness and **vertical gaze palsy** (Parinaud syndrome), which are absent in this patient's pure motor presentation. *Pons* - Pontine hemorrhages have a catastrophic presentation, typically causing a rapid descent into **coma**, **quadriplegia**, and classic **pinpoint pupils** due to disruption of descending sympathetic pathways. - The patient's presentation of contralateral hemiparesis without coma or pupillary changes is inconsistent with a pontine bleed. *Medulla* - Medullary hemorrhages are rare and cause specific brainstem syndromes like **Wallenberg syndrome**, characterized by vertigo, nystagmus, dysphagia, and ipsilateral facial numbness. - These syndromes involve complex crossed sensory and motor deficits, not the uniform contralateral motor weakness described in the question.

Question 17: What is the probable diagnosis for a patient who exhibits miosis, anhidrosis, mild ptosis, and a persistent small pupil even in low light conditions?

A. Horner syndrome (Correct Answer)
B. Argyll Robertson pupil
C. Marcus Gunn pupil
D. Adie's tonic pupil

Explanation: No changes were made to the text as none of the provided references reached the relevance threshold of 7/10 for the specific topic of Horner syndrome diagnosis and its differentials. The provided references largely discussed coagulation (mislabeled chapters), neurological signs of intracranial pressure, or general pupillary reflexes without specific diagnostic criteria for Horner syndrome or its differentiating features like anhidrosis.

Question 18: A 30-year-old male presents with deep-seated retro-orbital pain from cluster headache. What is the best management?

A. Oxygen (Correct Answer)
B. Verapamil
C. Lithium
D. Topiramate

Explanation: ***Oxygen*** - **High-flow oxygen** (100% at 7-15 L/min) is the safest and most effective **first-line abortive treatment** for an acute cluster headache attack [1] - It works rapidly to cause **vasoconstriction** and often terminates the severe retro-orbital pain within **15 to 20 minutes** - This is the preferred treatment for acute attacks due to its rapid onset and excellent safety profile *Verapamil* - Verapamil is a calcium channel blocker and is considered the **first-line prophylactic agent** for both episodic and chronic cluster headache, not acute treatment [1] - Its mechanism of action requires time, rendering it ineffective for terminating an ongoing acute pain episode - Used to prevent future attacks, not to abort current ones *Lithium* - Lithium is a prophylactic treatment reserved mainly for patients with **chronic cluster headache** or those who do not respond to Verapamil [1] - It has a slow onset of action and is not used to manage the acute pain of a cluster attack - Requires therapeutic monitoring due to narrow therapeutic window [1] *Topiramate* - Topiramate is an established prophylactic treatment primarily for **migraine**, and occasionally used as a second-line prophylactic agent for cluster headache - As a prophylactic medication, it plays **no role** in the acute termination or abortive management of a cluster headache episode

Question 19: A patient presents with symmetrical leg weakness and areflexia. He had developed diarrhoea 2 weeks ago. He was diagnosed as having GBS. What is the cause?

A. Cord inflammation
B. Demyelination of the spinal cord
C. Demyelination of A, B-fibers (Correct Answer)
D. Demyelination of B-fibers

Explanation: ***Demyelination of A, B-fibers***- GBS is an acute **demyelinating polyneuropathy** primarily affecting the myelin sheath of peripheral nerves and nerve roots (PNS involvement) [1].- Demyelination of large myelinated **A-fibers** (motor and sensory) explains the severe **symmetrical weakness** and **areflexia** [1]; demyelination of **B-fibers** contributes to common **autonomic dysfunction**.*Demyelination of B-fibers*- B-fibers are primarily **preganglionic autonomic fibers**; their demyelination causes autonomic instability (e.g., blood pressure fluctuation) but does not account for the profound motor weakness and areflexia that define GBS [2].- The cardinal features of GBS (weakness and areflexia) result from damage to the larger **A-fibers** (motor nerves) [1]. *Demyelination of the spinal cord*- GBS is a disease of the **Peripheral Nervous System (PNS)**, affecting nerve roots and peripheral nerves [2].- Demyelination confined to the spinal cord is characteristic of **Central Nervous System (CNS)** demyelinating diseases, such as **Transverse Myelitis** or **Multiple Sclerosis** [3]. *Cord inflammation*- **Spinal cord inflammation** or myelitis is a CNS process and typically results in upper motor neuron signs (spasticity, brisk reflexes) or distinct sensory levels, which are not seen in GBS.- GBS involves inflammation and attack on the **peripheral nerve myelin** or axons, specifically in the nerve roots and distal peripheral nerves [1].

Question 20: A 35-year-old female with progressive limb weakness for the past 1 year. On examination, muscle fasciculations and hypertonia are noted, and the sensory system is intact. What is the diagnosis?

A. Multifocal motor neuropathy
B. Becker muscular dystrophy
C. Spinal muscular atrophy
D. ALS (Correct Answer)

Explanation: ***Correct: ALS (Amyotrophic Lateral Sclerosis)*** - This patient presents with the classic triad of ALS: **progressive limb weakness, fasciculations (LMN sign), and hypertonia/spasticity (UMN sign)** [1] - The combination of **both upper and lower motor neuron signs** is pathognomonic for ALS [1] - **Sensory sparing** is characteristic - ALS affects motor neurons only [1] - Age and progressive course over 1 year fits the typical presentation - El Escorial criteria require UMN + LMN signs in multiple regions *Incorrect: Multifocal motor neuropathy* - This is a **pure lower motor neuron disorder** with conduction block - Would present with fasciculations and weakness but **NO hypertonia** (no UMN involvement) [1] - Treatable with immunotherapy, making it an important differential to exclude [1] *Incorrect: Becker muscular dystrophy* - This is a **primary muscle disease**, not a motor neuron disorder - **No fasciculations** would be present (fasciculations indicate motor neuron pathology) [2] - Predominantly affects males (X-linked), presents with proximal weakness and calf pseudohypertrophy - Elevated CK levels would be expected *Incorrect: Spinal muscular atrophy* - This is a **pure lower motor neuron disorder** due to anterior horn cell degeneration - Would NOT present with **hypertonia or UMN signs** - Typically presents in childhood/early life with symmetric proximal weakness - Associated with SMN1 gene mutations

Question 21: A young female presents with ptosis showing diurnal variation. CT chest shows an anterior mediastinal mass identified as thymus gland cancer. Which receptor is affected in this patient?

A. Acetylcholinesterase
B. Voltage-gated calcium channels at the NMJ
C. Presynaptic ACh Receptor
D. Post-synaptic ACh Receptor (Correct Answer)

Explanation: ***Post-synaptic ACh Receptor*** - The clinical presentation of **ptosis** with **diurnal variation** (worsening weakness throughout the day) and an associated **thymoma** are hallmark features of **Myasthenia Gravis** [1]. - Myasthenia Gravis is an autoimmune disorder characterized by antibodies that bind to and block or destroy **post-synaptic nicotinic acetylcholine (ACh) receptors** at the neuromuscular junction, leading to impaired muscle contraction [2]. *Presynaptic ACh Receptor* - Autoantibodies in common neuromuscular junction disorders do not target presynaptic ACh receptors. These receptors are typically involved in modulating neurotransmitter release via feedback mechanisms. - The primary presynaptic autoimmune disorder, **Lambert-Eaton Myasthenic Syndrome**, involves antibodies against voltage-gated calcium channels, not ACh receptors [3]. *Voltage-gated calcium channels at the NMJ* - This is the pathological target in **Lambert-Eaton Myasthenic Syndrome (LEMS)**, where antibodies inhibit presynaptic calcium influx, reducing acetylcholine release [3]. - LEMS is clinically distinct, often presenting with weakness that **improves with activity** (incremental response) and is strongly associated with **small cell lung cancer** [3]. *Acetylcholinesterase* - **Acetylcholinesterase (AChE)** is the enzyme responsible for degrading acetylcholine in the synaptic cleft; it is not the target of autoimmunity in Myasthenia Gravis. - In fact, **AChE inhibitors** (e.g., pyridostigmine) are a primary treatment for Myasthenia Gravis, as they increase the concentration and duration of ACh in the synapse to better activate the reduced number of receptors [2].

Question 22: A patient presents with unilateral throbbing pain, photophobia, nausea, and vomiting. The symptoms improve after taking sumatriptan. What is the most likely diagnosis?

A. Cluster headache
B. Sinus headache
C. Tension headache
D. Migraine (Correct Answer)

Explanation: ***Migraine*** - The presentation of **unilateral**, **throbbing pain** combined with associated symptoms like **photophobia**, **nausea**, and **vomiting** constitutes the classic criteria for migraine [1]. - Dramatic symptomatic relief after taking **sumatriptan** (a **triptan**) is highly characteristic, as these drugs are specific abortive treatments for acute **migraine** attacks. *Tension headache* - This headache is typically **bilateral**, described as a **tightening** or **band-like** pressure, and is non-throbbing [1]. - It usually lacks associated features such as **nausea**, **vomiting**, or severe photophobia, and does not typically respond well to triptans. *Cluster headache* - While also highly painful and unilateral, cluster headaches are characterized by **excruciating, non-throbbing** pain, often localized to the **periorbital** or retro-orbital region [1]. - Key associated features are **autonomic**, including ipsilateral **lacrimation**, ptosis, miosis, and rhinorrhea, features not mentioned in this presentation. *Sinus headache* - This diagnosis is associated with symptoms of **sinusitis**, such as facial pressure, pain over the sinuses, fever, and purulent nasal discharge. - The pain is usually localized to the **maxillary** or **frontal** regions and is not typically a severe, throbbing pain that uniquely responds to triptans.

Question 23: A 60 y/o male suddenly experiences an intense headache, described as the worst headache of his life, followed by vomiting and photophobia. O/E he has neck stiffness and a dilated pupil on the right side. A CT scan reveals bleeding in the subarachnoid space. Which of the following is the most common cause of this condition?

A. Hypertension
B. Intracranial aneurysm (Correct Answer)
C. Brain tumour
D. Arteriovenous malformation (AVM)

Explanation: ***Intracranial aneurysm***- Rupture of an intracranial **saccular (berry) aneurysm** accounts for approximately 85% of all non-traumatic subarachnoid hemorrhage (SAH) cases, making it the most common cause [2].- The classic presentation of the **"worst headache of his life"** (thunderclap headache), meningismus (**neck stiffness**), and potential Third nerve palsy (dilated pupil due to compression) are highly suggestive of aneurysmal SAH [1].*Hypertension*- Uncontrolled **chronic hypertension** is the leading cause of non-traumatic **intraparenchymal hemorrhage (ICH)**, typically affecting deep brain structures like the basal ganglia.- While hypertension is a major risk factor for SAH, it is not the primary mechanism of bleeding; the rupture of an aneurysm is the direct immediate cause [1].*Arteriovenous malformation (AVM)*- AVMs are abnormal connections that can rupture, causing hemorrhagic stroke, but they are the second most common cause of SAH, accounting for less than 10% of cases.- AVM rupture often leads to a combination of **intraparenchymal hemorrhage** and SAH, and they are typically associated with younger patients.*Brain tumour*- Tumors rarely cause acute, massive SAH; when they bleed, it typically occurs within the tumor mass itself (**intratumoral hemorrhage**).- The clinical presentation usually involves subacute onset of symptoms and progressive focal neurological deficits, rather than the sudden, dramatic thunderclap headache characteristic of SAH [1].

Question 24: A patient reports difficulty switching between movements and experiences uncontrollable hand movements. What is the most likely diagnosis?

A. Metamorphosis
B. Resting Tremor
C. Intentional Tremor
D. Dysdiadochokinesis (Correct Answer)

Explanation: ***Dysdiadochokinesis***- This term refers to the impairment in the ability to perform **rapid alternating movements**, directly matching the complaint of "difficulty switching between movements" [2].- It is a classic sign of **cerebellar dysfunction**, which also accounts for the associated **uncontrollable movements** (often reflecting associated **ataxia** or **dysmetria**) [3].*Intentional Tremor*- This tremor is absent at rest, but its amplitude increases significantly as the patient attempts to reach a **visual target** (e.g., during the finger-to-nose test).- While it is a sign of **cerebellar disease**, the primary complaint in the stem is difficulty *switching* movements, which is characteristic of **dysdiadochokinesis**.*Metamorphosis*- This neurological term typically refers to **perceptual distortion** (specifically, *metamorphopsia* is the distortion of visual size or shape), which is unrelated to motor control or coordination.- It is not the term used to describe the inability to perform **rapid alternating movements** or uncontrolled movements due to cerebellar pathology.*Resting Tremor*- A resting tremor is maximal when the limb is completely relaxed and **supported against gravity**, classically seen in **Parkinson's disease** [1].- This tremor usually **improves significantly** or disappears entirely when the patient performs voluntary action, distinguishing it from intentional tremors and general lack of coordination.

Question 25: A 35-year-old woman presents with fluctuating muscle weakness, especially affecting her speech and swallowing. Repetitive nerve stimulation shows a decremental response. Her blood tests are negative for acetylcholine receptor (AChR) antibodies. Which of the following antibodies is most likely responsible for her symptoms?

A. Anti-TPO antibodies
B. Anti-dsDNA antibodies
C. Anti-MuSK antibodies (Correct Answer)
D. Anti-Ro antibodies

Explanation: Detailed clinical evaluation of myasthenia gravis reveals that anti-MuSK antibodies target Muscle-Specific Kinase (MuSK), essential for clustering AChR at the NMJ [1]. Their presence confirms the diagnosis of Myasthenia Gravis (MG) in patients who are seronegative for AChR antibodies, often presenting with prominent bulbar and facial weakness [1]. Anti-dsDNA antibodies are specific for Systemic Lupus Erythematosus (SLE), an autoimmune disease that primarily causes arthritis, renal disease, and malar rash [2]. Although SLE can cause myositis or neuropathy, it does not typically present with the isolated, fluctuating postsynaptic weakness characteristic of Myasthenia Gravis and the decremental response. Anti-thyroid peroxidase (TPO) antibodies are primary markers for Hashimoto's thyroiditis, leading to hypothyroidism; screening for associated autoimmune thyroid disease is recommended in MG patients [1]. Anti-Ro antibodies, characteristic of Sjögren's Syndrome and SLE [2], primarily involve sicca symptoms and occasionally present with myositis, but not the hallmark features of ocular or bulbar MG.

Question 26: A patient presents with acute onset symmetric lower limb flaccid paralysis and absent deep tendon reflexes. Which condition is most likely?

A. Multiple sclerosis
B. Spinal cord injury
C. Amyotrophic lateral sclerosis
D. Guillain-Barré syndrome (Correct Answer)

Explanation: ***Guillain-Barré syndrome*** - This acute disorder is a **peripheral neuropathy** characterized by ascending, rapidly worsening, **symmetric weakness (flaccidity)** [1]. - The key distinguishing feature is the early and profound loss of deep tendon reflexes known as **areflexia**, corresponding to the damage of peripheral motor nerves/roots (a true lower motor neuron syndrome) [1]. *Multiple sclerosis* - MS is a **central nervous system** disorder causing demyelination in the brain and spinal cord, typically resulting in **upper motor neuron signs**. - Symptoms typically include spasticity, hyperreflexia, and sensory deficits, which directly contrast with the flaccidity and areflexia seen in this patient. *Amyotrophic lateral sclerosis* - ALS involves damage to both upper and lower motor neurons; while it causes LMN symptoms like flaccidity and atrophy, there is often concurrent **hyperreflexia or mixed reflexes** (UMN involvement) [2]. - It is a chronic, progressive neuronal disorder, not primarily defined by the acute, global **areflexia** consistent with GBS [2]. *Spinal cord injury* - Acute spinal cord injury leads to **spinal shock**, causing transient flaccid paralysis and areflexia below the level of the lesion, which eventually evolves into **spasticity and hyperreflexia**. - Unless the injury involves the **cauda equina** (LMN structure), persistent LMN signs with areflexia below the injury level are usually temporary or localized.

Question 27: A patient presents with the palsy of the face as shown. Which of the following is most likely involved?

A. Erb's palsy
B. 3rd nerve palsy
C. 7th nerve palsy (Correct Answer)
D. Orbicularis oculi palsy

Explanation: ***7th nerve palsy*** - The image shows features of a **lower motor neuron (LMN) lesion** of the **7th cranial (facial) nerve**, affecting both the upper and lower face. Note the inability to wrinkle the left forehead, incomplete eye closure, and drooping of the left corner of the mouth. - This condition, often idiopathic and termed **Bell's palsy**, results in paralysis of all ipsilateral muscles of facial expression, which are innervated by the facial nerve. *3rd nerve palsy* - A **3rd cranial nerve (oculomotor)** palsy would present with **ptosis** (drooping eyelid), a dilated pupil, and the eye positioned "down and out" due to unopposed action of the superior oblique and lateral rectus muscles. - It does not cause paralysis of the lower facial muscles, such as those involved in smiling. *Erb's palsy* - This is an injury to the **upper trunk (C5-C6)** of the **brachial plexus**, typically occurring at birth, which affects the muscles of the shoulder and arm. - It results in the characteristic "**waiter's tip**" posture of the arm and has no effect on the facial muscles. *Orbicularis oculi palsy* - This describes an isolated paralysis of the muscle that closes the eyelids. While this is a component of 7th nerve palsy, it is not the complete diagnosis. - The patient clearly has paralysis of other facial muscles, such as the **frontalis** (forehead) and **zygomaticus** (mouth), indicating a lesion of the main facial nerve trunk, not just a single branch.

Question 28: A young male presented with weakness in the lower half of the right side of his face, with drooping of the angle of his mouth. He is unable to raise his eyebrows and close his eyes on the right side. Which of the following is the most appropriate diagnosis?

A. Supranuclear facial palsy on left side
B. Infranuclear facial palsy on right side (Correct Answer)
C. Infranuclear facial on left side
D. Supranuclear facial on right side

Explanation: ***Infranuclear facial palsy on right side***- **Infranuclear (peripheral) facial palsy** involves the facial nerve (CN VII) distal to the nucleus, causing paralysis of the entire ipsilateral side of the face.- The inability to move the upper facial muscles (closing the eye, raising the eyebrow) combined with lower face weakness (mouth drooping) on the right side indicates complete paralysis of the **right facial nerve**.*Supranuclear facial palsy on left side*- A **supranuclear (central) lesion** (e.g., stroke) affects the face contralaterally, leading to weakness on the right face, but the upper face (forehead) would be spared [1].- The ability to move the forehead is preserved in supranuclear palsy because the upper facial nucleus receives bilateral cortical input, which contradicts the bilateral/right upper face involvement described here [1].*Infranuclear facial on left side*- This diagnosis would cause complete paralysis (upper and lower face) on the **left side**.- The patient presents with clinical signs of paralysis (drooping mouth, inability to raise eyebrow) primarily on the **right side**, making a left-sided lesion incorrect.*Supranuclear facial on right side*- A **supranuclear lesion** on the right side would cause weakness of the muscles of the **left lower face** (contralateral presentation).- Supranuclear lesions never cause involvement of the upper facial muscles (unable to raise eyebrows) as seen in this patient [1].

Question 29: Bell's palsy involves

A. Contralateral upper and lower halves of the face.
B. Ipsilateral lower half of the face.
C. Contralateral lower half of the face.
D. Ipsilateral upper and lower halves of the face. (Correct Answer)

Explanation: ***Ipsilateral upper and lower halves of the face.*** - **Bell's palsy** is the most common cause of **idiopathic peripheral (Lower Motor Neuron - LMN)** facial nerve paralysis [1]. - A peripheral (LMN) lesion affects the **entire distribution** of the facial nerve on the affected side, resulting in paralysis of all muscles, including those controlling the forehead and eye closure. - Facial nerve palsies affect the **ipsilateral** side of the face relative to the site of peripheral nerve injury or brainstem nuclear lesion. *Contralateral upper and lower halves of the face.* - This presentation would imply a **bilateral upper and lower facial paralysis**, which is highly unusual for a single lesion like Bell's palsy. - Facial nerve palsies affect the **ipsilateral** side of the face, not contralateral. *Ipsilateral lower half of the face.* - Paralysis limited to the **ipsilateral lower half of the face** while sparing the upper face (forehead) is characteristic of a **Central (Upper Motor Neuron - UMN)** lesion (like a stroke) located in the contralateral cortex [1]. - This does not define Bell's palsy, which is a **peripheral (LMN)** lesion affecting the entire face. *Contralateral lower half of the face.* - This pattern, involving **paralysis of the lower face contralateral** to the lesion while sparing the forehead, is the classic presentation of a **Central (Upper Motor Neuron - UMN)** lesion [1]. - UMN lesions spare the upper face because the **facial nerve nucleus** receives bilateral cortical input for the muscles of the forehead.

Question 30: A woman presents with a history of headaches for the past 9 months that worsen in a recumbent position and improves as the day progresses. She also gives a history of taking oral contraceptives. Fundal examination shows papilledema. There are no focal neurological deficits. What is the probable cause of her headaches?

A. Myasthenia gravis
B. Temporal arteritis
C. Chronic migraine
D. Pseudotumor cerebri (Correct Answer)

Explanation: ***Pseudotumor cerebri*** - The presentation of headache that worsens in the **recumbent position** (due to increased intracranial pressure, ICP) and improves when upright is highly characteristic of **Idiopathic Intracranial Hypertension (IIH)** [1]. - Confirmation of **papilledema** (swollen optic disc) in a young, likely obese female taking **oral contraceptives** (a risk factor) without other focal signs confirms the diagnosis of **pseudotumor cerebri** [1]. *Myasthenia gravis* - This disease is a neuromuscular disorder characterized by fluctuating **muscle weakness** (diplopia, ptosis, difficulty chewing) that worsens with activity and improves with rest. - It is not associated with primary headache or signs of increased intracranial pressure like **papilledema**. *Temporal arteritis* - This diagnosis is reserved for older patients (usually >50 years) presenting with severe localized headache, **jaw claudication**, tenderness over the temporal artery, and elevated inflammatory markers (ESR/CRP) [2]. - The positional nature of the headache and the patient's young age (implied by OCP use, a risk factor for IIH) make this diagnosis unlikely. *Chronic migraine* - Migraine is a diagnosis of exclusion that typically involves severe, often **pulsatile** headaches, sometimes with aura, photophobia, or nausea [3]. - While chronic migraine involves frequent headaches, it does not cause **papilledema** or have headaches classically exacerbated by the **recumbent position**, which points instead toward a structural or ICP-related etiology [2].

Question 31: A 26-year-old male with a history of respiratory tract infection 4 weeks ago is unable to stand or walk for the past 2 weeks and the weakness is progressive, ascending, and symmetrical in nature. The lower limbs were involved before and gradually the upper limbs were also affected. On examination you note areflexia. Pain and proprioception are preserved. What is the probable diagnosis?

A. Guillain Barre syndrome (Correct Answer)
B. Myasthenia gravis
C. Polymyositis
D. Multiple sclerosis

Explanation: ***Guillain Barre syndrome*** - **Acute inflammatory demyelinating polyradiculoneuropathy (AIDP)** - most common GBS variant [1] - Classic presentation: **progressive, ascending, symmetrical weakness** starting in lower limbs [1] - **Areflexia** is a hallmark feature due to peripheral nerve involvement [1] - **Preceding infection** (respiratory or gastrointestinal) occurs in 60-70% of cases, typically 1-4 weeks prior [1] - **Preserved sensory examination** for pain and proprioception (though may have paresthesias) [1] - **Motor weakness predominates** over sensory symptoms [1] - Diagnosis confirmed by: CSF showing albuminocytologic dissociation, nerve conduction studies showing demyelination - Treatment: **IV immunoglobulin (IVIG)** or **plasmapheresis** *Myasthenia gravis* - Presents with **fatigable weakness**, worsens with activity - **Ocular and bulbar muscles** typically affected first (ptosis, diplopia, dysphagia) - **Reflexes are preserved** (not areflexia) - No ascending pattern of weakness - Positive acetylcholine receptor antibodies, abnormal repetitive nerve stimulation *Polymyositis* - **Proximal muscle weakness** (shoulder and hip girdle), not ascending pattern - **Subacute onset** over weeks to months (not acute 2 weeks) - **Elevated creatine kinase (CK)** levels - Reflexes typically preserved initially - Muscle biopsy shows inflammatory infiltrates *Multiple sclerosis* - **Relapsing-remitting pattern** with episodes separated in time and space - **Sensory symptoms prominent** (numbness, tingling, vision changes) - **Hyperreflexia** with upper motor neuron signs (not areflexia) - Does not present with acute ascending paralysis - MRI shows demyelinating plaques in CNS

Question 32: A young male patient presents with ptosis and muscle weakness, which reportedly worsens in the evening and improves in the morning. This is relieved by neostigmine. What is the likely diagnosis?

A. Myasthenia gravis (Correct Answer)
B. Huntington chorea
C. Amyotrophic lateral sclerosis
D. External ophthalmoplegia

Explanation: ***Myasthenia gravis***- The presentation of muscle weakness, specifically **ptosis**, that worsens with fatigue (evening) or activity and improves with rest (morning), is the classic hallmark of the autoimmune condition **Myasthenia Gravis (MG)**.- The dramatic improvement upon administration of **neostigmine** (an acetylcholinesterase inhibitor) is diagnostic, confirming impaired transmission at the **neuromuscular junction** due to autoantibodies against **acetylcholine receptors (AChR)** [1].*Huntington chorea*- This is a progressive, inherited neurodegenerative disorder primarily characterized by involuntary, jerky movements (**chorea**) and cognitive decline. - It is related to excessive CAG trinucleotide repeats on chromosome 4, leading to neuronal loss in the **caudate nucleus**, and does not respond to neostigmine.*Amyotrophic lateral sclerosis*- ALS is a motor neuron disease characterized by progressive and unrelenting weakness due to the loss of both **upper and lower motor neurons**.- The weakness in ALS is permanent, not fluctuating diurnally, and does not improve with acetylcholinesterase inhibitors like neostigmine.*External ophthalmoplegia*- This is a descriptive term referring to weakness or paralysis of the external eye muscles; while it is often seen in MG (where it is often called ocular MG), it is a symptom, not the overall diagnosis.- This term does not explain the generalized muscle weakness, the pattern of **fatigability**, or the characteristic response to **neostigmine**.

Question 33: What is the drug of choice for this medical condition showing periventricular lesions?

A. α-interferon
B. β-interferon (Correct Answer)
C. □-interferon
D. Natalizumab

Explanation: ***β-interferon*** - The MRI image shows **periventricular white matter lesions** which are characteristic of **Multiple Sclerosis (MS)**. - **Beta-interferons (β-interferon)** are a cornerstone in the treatment of **relapsing-remitting multiple sclerosis (RRMS)**, acting as disease-modifying therapies to reduce the frequency and severity of relapses and slow disease progression. *α-interferon* - **Alpha-interferon (α-interferon)** is primarily used in the treatment of certain **cancers** and **viral infections** (e.g., hepatitis B and C), not for demyelinating diseases like MS. - It has a different spectrum of biological activities and clinical applications compared to beta-interferons. *□-interferon* - The option "□-interferon" is not a recognized or standard classification for interferon subtypes in medical or pharmaceutical contexts. - This option is likely a distractor and does not represent a known therapeutic agent for any condition, including MS. *Natalizumab* - **Natalizumab** is a highly effective disease-modifying therapy for MS, but it is typically reserved for patients with **highly active MS** or those who have responded inadequately to other treatments, such as beta-interferons. - While effective, it carries a risk of inducing **progressive multifocal leukoencephalopathy (PML)**, making it a second-line or escalated therapy rather than the initial drug of choice for MS.

Question 34: Which of the following is incorrect about the condition shown below?

A. Most common CT finding is intraventricular calcification (Correct Answer)
B. Most common presentation is partial seizures
C. Albendazole is given for 8 days
D. Steroids help in alleviating vasogenic oedema of ring enhancing lesion

Explanation: ***Most common CT finding is intraventricular calcification*** - This statement is **incorrect**. In neurocysticercosis, the most common CT finding is **parenchymal calcifications**, which represent the remnants of dead cysts, rather than intraventricular calcifications. - **Intraventricular calcifications** are possible but less frequent than parenchymal lesions and often arise from degenerating intraventricular cysts leading to obstructive hydrocephalus. *Most common presentation is partial seizures* - This statement is **correct**. **Partial seizures** (also known as focal seizures) are indeed the most common clinical presentation of neurocysticercosis, especially when **parenchymal cysts** are involved. - This is due to the cysts acting as a **focal irritant** within the cerebral cortex, leading to abnormal electrical activity. *Albendazole is given for 8 days* - This statement is **correct**. For neurocysticercosis, **Albendazole** is typically administered for a duration ranging from **8 days to 30 days**, depending on the number, location, and stage of the cysts. - The precise duration can vary based on clinical response and cyst resolution observed on follow-up imaging. *Steroids help in alleviating vasogenic oedema of ring enhancing lesion* - This statement is **correct**. **Corticosteroids**, such as dexamethasone, are frequently co-administered with anti-parasitic drugs like albendazole to manage the **inflammatory response** (vasogenic edema) caused by the dying parasites. - This edema often surrounds the **ring-enhancing lesions** seen on imaging and can exacerbate symptoms like seizures and headaches.

Question 35: A 15-year-old boy presented with day dreaming and decline in school performance. EEG shows.

A. Atonic seizure
B. Myoclonic seizure
C. Typical absence seizure (Correct Answer)
D. Atypical absence seizure

Explanation: ***Typical absence seizure*** - The clinical presentation of **daydreaming** and decline in school performance in a 15-year-old is classic for absence seizures. - The EEG shows a characteristic **generalized 3 Hz spike-and-wave discharge**, which is pathognomonic for typical absence seizures. *Atonic seizure* - Characterized by a **sudden loss of muscle tone**, leading to falls, often referred to as "drop attacks." - EEG in atonic seizures often shows **polyspike-and-wave discharges** or generalized slow waves, but not the 3 Hz spike-and-wave pattern. *Myoclonic seizure* - Involves **brief, shock-like jerks** of a muscle or group of muscles, without loss of consciousness. - EEG typically shows **generalized polyspike-and-wave discharges** or fast spike-and-wave activity, which differs from the 3 Hz pattern. *Atypical absence seizure* - Clinical features include a **less abrupt onset and termination** of altered consciousness, often accompanied by changes in muscle tone. - EEG shows **slower spike-and-wave complexes (typically 1.5-2.5 Hz)** and more heterogeneous patterns than typical absence seizures.

Question 36: Which of the following is true regarding type of seizures shown in EEG?

A. Attack lasts for 60 to 90 seconds
B. Hyperventilation often precipitates an attack (Correct Answer)
C. Onset of disease in the first year of life
D. Attack followed by postictal confusion

Explanation: ***Hyperventilation often precipitates an attack*** - The EEG shows a classic **3-Hz spike-and-wave pattern**, which is characteristic of **absence seizures**. - **Hyperventilation** is a common and effective activation procedure used during EEG recordings to **induce or exacerbate absence seizures**, making them more apparent. *Attack lasts for 60 to 90 seconds* - **Absence seizures** are typically brief, usually lasting only **5 to 30 seconds**, much shorter than the 60-90 seconds stated. - Longer seizures, especially those with postictal confusion, are more characteristic of **complex partial seizures** or **tonic-clonic seizures**. *Onset of disease in the first year of life* - **Childhood absence epilepsy** typically has an onset between **4 and 8 years of age**, with a peak around 5-6 years. - Seizures appearing in the first year of life would suggest other epilepsy syndromes, such as ** infantile spasms** or severe myoclonic epilepsy in infancy (Dravet syndrome). *Attack followed by postictal confusion* - Absence seizures are classic for **lacking a postictal period**; the individual typically resumes activity immediately after the seizure ends without confusion or disorientation. - **Postictal confusion** is a hallmark feature of **tonic-clonic seizures** and often complex partial seizures, indicating a more widespread and prolonged disruption of brain activity.

Question 37: A patient presents with facial deviation to the right, inability to close the left eye with Bell's sign, and unclear ability to produce wrinkles on the forehead based on the image. What is the most likely diagnosis?

A. Right upper motor neuron lesion
B. Left upper motor neuron (UMN/central) lesion
C. Left lower motor neuron (LMN/peripheral) lesion (Correct Answer)
D. Right lower motor neuron lesion

Explanation: ***Left lower motor neuron (LMN/peripheral) lesion*** - Facial deviation to the **right** indicates weakness of the **left facial muscles**, as the unaffected right side pulls the face toward it. - Complete involvement of **forehead muscles** (inability to wrinkle forehead) along with **Bell's sign** indicates a **peripheral/LMN lesion** affecting the entire facial nerve. *Left upper motor neuron (UMN/central) lesion* - **Central lesions** typically **spare forehead muscles** due to bilateral cortical innervation of the upper facial muscles. - Would not cause complete facial paralysis including forehead involvement as seen in this case. *Right lower motor neuron lesion* - A **right-sided lesion** would cause facial deviation to the **left**, not to the right as described. - The clinical presentation clearly indicates **left-sided facial weakness**, not right-sided. *Right upper motor neuron lesion* - Would cause facial deviation to the **left side**, opposite to what is observed in this patient. - **Central lesions** spare the forehead due to **bilateral cortical representation**, which contradicts the forehead involvement seen here.

Question 38: The following diagram and its branches should be remembered. The blood vessel involved in medial medullary syndrome is anterior spinal artery.

A. Choice A
B. Choice B: Anterior spinal artery (Correct Answer)
C. Choice C
D. Choice D

Explanation: ***Choice B: Anterior spinal artery*** - The **anterior spinal artery** supplies the medial medulla, and its occlusion leads to **medial medullary syndrome**. - This syndrome is characterized by contralateral hemiparesis (due to involvement of the pyramidal tract), contralateral loss of proprioception and vibratory sensation (due to medial lemniscus involvement), and ipsilateral tongue deviation (due to hypoglossal nerve nucleus involvement).

Question 39: Which of the following is characteristic of Parinaud's syndrome?

A. Dorsal midbrain lesion (Correct Answer)
B. Ventral midbrain lesion
C. Thalamic lesion
D. Pontine lesion

Explanation: ***Dorsal midbrain lesion*** - Parinaud's syndrome, also known as the **dorsal midbrain syndrome**, is characterized by a constellation of symptoms resulting from damage to the **tectal plate** and **pretectal area** of the midbrain. - This damage often affects the **superior colliculi** and adjacent structures, impairing **vertical gaze** and **pupillary reflexes**. *Ventral midbrain lesion* - Lesions in the **ventral midbrain** typically affect the **substantia nigra** and **cerebral peduncles**, causing different symptoms. - This location would result in **parkinsonian features** or **hemiparesis**, not the characteristic eye movement abnormalities of Parinaud's syndrome. *Pontine lesion* - Pontine lesions commonly cause **horizontal gaze palsy** and **internuclear ophthalmoplegia**, not vertical gaze dysfunction. - The **paramedian pontine reticular formation (PPRF)** controls horizontal eye movements, distinct from the vertical gaze control in the midbrain. *Thalamic lesion* - Thalamic lesions typically cause **altered consciousness**, **memory deficits**, or **sensory disturbances**. - While some thalamic lesions can affect eye movements, they don't produce the specific **upward gaze paralysis** and **light-near dissociation** seen in Parinaud's syndrome.

Question 40: The EEG of a 16-year-old boy with early morning involuntary movements of hands in his sleep noticed by parents, was performed. Immunization is complete. What does EEG show? (Recent NEET Pattern 2016-17)

A. Juvenile myoclonic epilepsy (Correct Answer)
B. SSPE
C. Benign rolandic epilepsy
D. Huntington chorea

Explanation: ***Juvenile myoclonic epilepsy*** - The EEG shows generalized **polyspike-and-slow-wave discharges**, which are characteristic of juvenile myoclonic epilepsy (JME), especially when associated with early morning myoclonus. - The clinical presentation of a **16-year-old boy** with **involuntary movements of hands in his sleep** (suggesting myoclonic jerks), particularly in the morning, is highly consistent with JME. *SSPE* - Subacute sclerosing panencephalitis (SSPE) typically presents with characteristic EEG patterns like **Radermacker complexes** or **periodic complexes**, which are not seen here. - Clinical features of SSPE include progressive cognitive decline, myoclonus, and other neurological deficits, usually following a measles infection, which are not described. *Benign rolandic epilepsy* - Benign rolandic epilepsy (BRE) is characterized by **centrotemporal spikes** on EEG, often exacerbated by sleep, and presents with focal seizures affecting the face and mouth. - The generalized polyspike-and-slow-wave pattern and the clinical description of hand myoclonus do not fit the profile of BRE. *Huntington chorea* - Huntington's chorea is a **neurodegenerative genetic disorder** characterized by involuntary movements (chorea), cognitive decline, and psychiatric problems. - EEG findings in Huntington's chorea are often non-specific or show generalized slowing, and it is not an epilepsy syndrome with specific high-amplitude epileptiform discharges like those seen.

Question 41: The EEG of the patient shows which of the following? (Recent NEET Pattern 2016-17)

A. Burst suppression pattern (Correct Answer)
B. Rademecker complex
C. 3/sec spike and slow wave pattern
D. 4-6 Hz Polyspike

Explanation: ***Burst suppression pattern*** - The EEG shows periods of high amplitude, mixed-frequency **bursts of activity** alternating with periods of **relative electrical silence** (suppression). - This pattern is often seen in conditions like severe **hypoxic-ischemic encephalopathy**, deep **anesthesia**, or severe brain injury. *Rademecker complex* - This refers to periodic trifasic complexes, often associated with subacute sclerosing panencephalitis (SSPE), which is a **slow viral infection** of the brain. - The complexes are typically **bilateral, synchronous, and repetitive**, not characterized by alternating bursts and suppression. *3/sec spike and slow wave pattern* - This pattern is characteristic of **absence seizures (petit mal epilepsy)**, where there are generalized, synchronous 3 Hz spike-and-wave discharges. - The image does not show continuous, rhythmic 3 Hz activity but rather alternating periods of activity and flat-lining. *4-6 Hz Polyspike* - Polyspikes are a series of two or more spikes or sharp waves clustered together, often associated with **myoclonic seizures** or other generalized epilepsies. - While there are some sharp waves in the burst phases, the overall pattern is dominated by the distinct periods of suppression, not continuous polyspike activity.

Question 42: A 65-year-old man with dementia and poor hygiene due to urinary incontinence was evaluated. On examination: Deep tendon reflexes are brisk and gait apraxia with start hesitation is noted. CT scan was performed. What is the diagnosis?

A. Alzheimer's disease
B. Multi-infarct dementia
C. Normal pressure hydrocephalus (Correct Answer)
D. Frontal lobe tumor

Explanation: ***Normal pressure hydrocephalus*** - The classic triad of **dementia**, **gait apraxia**, and **urinary incontinence** strongly points to normal pressure hydrocephalus (NPH). The CT scan shows **ventriculomegaly out of proportion to sulcal atrophy**, a key finding in NPH. - The symptoms are often reversible with **ventriculoperitoneal shunting**, making early diagnosis crucial. *Alzheimer's disease* - While it causes **dementia**, it does not typically present with gait apraxia or urinary incontinence as prominent initial features. - CT scans in Alzheimer's usually show **diffuse cerebral atrophy**, not significant ventriculomegaly disproportionate to sulcal changes. *Multi-infarct dementia* - Characterized by a **stepwise decline** in cognitive function and focal neurological deficits related to cerebrovascular events. - CT scans would typically show evidence of **multiple infarcts** or vascular lesions, which are not explicitly described as the primary finding. *Frontal lobe tumor* - Could cause dementia and gait issues, but it would typically present with other focal neurological signs depending on the tumor's location and size, as well as **mass effect or edema** on neuroimaging. - The presented symptoms align more specifically with NPH than a generalized tumor effect without additional details.

Question 43: Identify the neurocutaneous disorder.

A. Sturge-Weber syndrome (Correct Answer)
B. Von Hippel-Lindau syndrome
C. Tuberous sclerosis
D. Ataxia telangiectasia

Explanation: ***Sturge-Weber syndrome*** - This image displays a typical **leptomeningeal angioma** on CT (often calcified, appearing as brain calcifications over the surface of the brain) and a **port-wine stain** (nevus flammeus) on the face, characteristic features of Sturge-Weber syndrome. - Sturge-Weber syndrome is a **neurocutaneous disorder** characterized by vascular malformations affecting the brain, eyes, and skin, presenting with these specific features. *Von Hippel-Lindau syndrome* - This syndrome is characterized by the development of **hemangioblastomas** in the brain, spinal cord, and retina, and an increased risk of renal cell carcinoma and pheochromocytoma. - It does not typically present with a port-wine stain or the specific leptomeningeal angioma seen in the image. *Tuberous sclerosis* - Tuberous sclerosis features **non-cancerous tumors** in various organs, including the brain (cortical tubers, subependymal nodules), kidneys, heart, and skin (e.g., facial angiofibromas, ash-leaf spots). - While it is a neurocutaneous disorder, the imaging and skin findings in the question do not align with the characteristic features of tuberous sclerosis. *Ataxia telangiectasia* - Ataxia telangiectasia is a rare, inherited disorder that affects multiple body systems, causing **progressive neurological problems** (ataxia), **immunodeficiency**, and an increased risk of cancer. - Its skin manifestations typically include **telangiectasias** (spider veins) on the skin and eyes, particularly noticeable in the eyes, which are not depicted in the image.

Question 44: A patient presents with GCS of 7 with nuchal rigidity and bloody CSF. Which is incorrect regarding this condition? (Recent NEET Pattern 2016-17)

A. Blood in sylvian fissure
B. Seizures
C. Intraventricular extension
D. IV ceftriaxone (Correct Answer)

Explanation: **IV ceftriaxone** - The clinical presentation of **GCS of 7**, **nuchal rigidity**, and **bloody CSF** is highly suggestive of a **subarachnoid hemorrhage (SAH)**, not a bacterial infection like meningitis. - **Ceftriaxone** is an antibiotic commonly used to treat bacterial meningitis, which is not indicated here as the primary issue is hemorrhage, not infection. *Blood in sylvian fissure* - **Blood in the sylvian fissure** is a common finding in **subarachnoid hemorrhage**, as this area contains major cerebral arteries susceptible to aneurysm rupture. - CT scans often show hyperdense (bright) blood within the sulci and cisterns, including the sylvian fissure. *Seizures* - **Seizures** are a relatively common complication of **subarachnoid hemorrhage**, especially in the acute phase due to blood irritating the cerebral cortex. - They can occur in up to 10-20% of SAH patients and are a significant predictor of poorer outcomes. *Intraventricular extension* - **Intraventricular extension** of blood indicates a more severe hemorrhage and is often associated with a worse prognosis in **subarachnoid hemorrhage**. - The presence of blood within the ventricles can lead to **hydrocephalus** and increased intracranial pressure.

Question 45: A 50-year-old hypertensive patient develops sudden onset drooping of right face and hemiplegia. What is the diagnosis?

A. MCA area hemorrhage (Correct Answer)
B. ACA area infarction
C. ACA area hemorrhage
D. MCA area infarction

Explanation: ***MCA area hemorrhage*** - The **hyperdense lesion** on CT scan indicates **acute hemorrhage** in the MCA territory, which correlates with the sudden onset right facial droop and hemiplegia. - **Hypertension** is the most common risk factor for primary **intracerebral hemorrhage**, and MCA territory involvement typically causes contralateral face and arm weakness. *MCA area infarction* - **Infarctions** appear as **hypodense (dark) areas** on CT scan, not hyperdense lesions as described in this case. - While MCA infarction can cause similar clinical symptoms, the imaging findings clearly show hemorrhage rather than ischemic changes. *ACA area infarction* - **ACA infarction** typically presents with **leg weakness** more prominent than face/arm weakness, as the ACA supplies the medial motor cortex for lower limbs. - The imaging shows a **hyperdense hemorrhage**, not the **hypodense appearance** characteristic of infarction. *ACA area hemorrhage* - **ACA territory hemorrhage** would affect the **frontal lobe**, causing symptoms like leg weakness, **abulia** (lack of motivation), and urinary incontinence. - The clinical presentation of **facial droop and hemiplegia** involving face and arm is more characteristic of **MCA involvement** rather than ACA territory.

Question 46: Which is correct for the image shown below?

A. Jendrassik maneuver (Correct Answer)
B. Wartenberg sign
C. Hoffman sign
D. Gordon sign

Explanation: ***Jendrassik maneuver*** - The image shows a patient interlocking their fingers and pulling them apart while a patellar reflex is being tested, which is characteristic of the **Jendrassik maneuver**. - This maneuver is used to **distract the patient** and enhance the amplitude of muscle stretch reflexes, making them more perceptible. *Wartenberg sign* - The Wartenberg sign is observed when the **little finger spontaneously abducts** due to weakness of the adductor pollicis muscle, often indicating ulnar nerve neuropathy. - This sign involves observation of a specific hand posture, not an active maneuver by the patient to improve reflex testing. *Hoffman sign* - The Hoffman sign is elicited by flicking the distal phalanx of the patient's middle finger, and a positive response involves **involuntary flexion of other fingers and the thumb**. - It is an indicator of **upper motor neuron dysfunction** and is not depicted in this image. *Gordon sign* - The Gordon sign is a plantar reflex elicited by **squeezing the calf muscle**, resulting in an extensor plantar response (dorsiflexion of the great toe and fanning of other toes). - This sign is a variant of the Babinski reflex and is used to detect **pyramidal tract lesions**, which is not what is shown.

Question 47: Which reflex is being elicited in the patient?

A. Wartenberg reflex
B. Finger flexion reflex
C. Supinator jerk
D. Hoffmann reflex (Correct Answer)

Explanation: ***Hoffmann reflex*** - The image shows the examiner **flicking the middle finger of the patient upward**, which is the technique used to elicit the Hoffmann reflex. - A positive Hoffmann reflex involves **involuntary flexion of the thumb and index finger** in response to this flick, indicating upper motor neuron dysfunction. *Wartenberg reflex* - This reflex is elicited by rapid abduction and adduction of the patient's fingers, which is not depicted in the image. - A positive Wartenberg reflex involves the patient being unable to relax from the abducted position, indicating ulnar nerve entrapment. *Finger flexion reflex* - While the Hoffmann reflex does involve finger flexion, "finger flexion reflex" is not a specific, recognized neurological reflex test with the exact technique shown. - This term is too general and does not precisely describe the specific maneuver being performed. *Supinator jerk* - The supinator jerk (also known as the brachioradialis reflex) is elicited by **tapping the brachioradialis tendon** near the wrist with a reflex hammer. - This technique is distinctly different from the flicking of the middle finger shown in the image.

Question 48: All are correct about the reflex being elicited except:

A. Exaggerated abdominal reflexes can be seen in psychoneurosis
B. Repeated pregnancies may lead to absent abdominal reflex
C. Root value of upper abdomen is T7-T9
D. Beevor sign is caudal movement of umbilicus on attempt to flex neck and upper trunk (Correct Answer)

Explanation: ***Beevor sign is caudal movement of umbilicus on attempt to flex neck and upper trunk*** - The Beevor sign describes the **upward movement of the umbilicus** when the patient attempts to flex their neck and upper trunk, due to weakness of the lower abdominal wall muscles. - The image illustrates the elicitation of the **abdominal reflex**, not the Beevor sign. *Exaggerated abdominal reflexes can be seen in psychoneurosis* - While **exaggerated deep tendon reflexes** can sometimes be found in conditions like psychoneurosis, abdominal reflexes are typically observed to be normal or sometimes absent. - Exaggerated superficial reflexes like the abdominal reflex are **not a typical finding** in psychoneurosis and might suggest other neurological issues. *Repeated pregnancies may lead to absent abdominal reflex* - **Repeated pregnancies** and conditions causing stretching of the abdominal wall, such as obesity, can indeed lead to **absent abdominal reflexes** due to laxity of the abdominal muscles and connective tissue. - The reflex pathway itself is intact, but the muscle response may be diminished or absent due to **mechanical factors**. *Root value of upper abdomen is T7-T9* - The **upper abdominal reflex** is indeed mediated by spinal cord segments **T7-T9**. - The middle abdominal reflex is mediated by T9-T10, and the lower abdominal reflex by T11-T12.

Question 49: All are true about the reflex being elicited except?

A. Afferent nerve is femoral nerve (Correct Answer)
B. Efferent nerve is genitofemoral nerve
C. The root value is L1,2
D. The inner part of thigh is stroked in upward and outward directions

Explanation: ***Afferent nerve is femoral nerve*** - The **cremasteric reflex** has its afferent limb carried by the **ilioinguinal nerve** and the **genitofemoral nerve**. - The femoral nerve is primarily responsible for motor and sensory innervation to the anterior thigh, not the cremasteric reflex. *Efferent nerve is genitofemoral nerve* - This statement is true; the **efferent limb** of the cremasteric reflex is indeed carried by the **genitofemoral nerve**, which innervates the cremaster muscle. - The genitofemoral nerve, through its genital branch, causes the contraction of the cremaster muscle, leading to the elevation of the testis. *The root value is L1,2* - This statement is true; the **cremasteric reflex** arc primarily involves spinal cord segments **L1 and L2**. - This root value signifies the origin of the nerves involved in both the afferent and efferent pathways of the reflex. *The inner part of thigh is stroked in upward and outward directions* - This statement is true regarding the technique for eliciting the **cremasteric reflex**. - Stroking the **inner part of the thigh** (proximally toward the abdomen) stimulates sensory fibers that initiate the reflex, causing the ipsilateral testis to elevate.

Question 50: The EEG shows presence of:

A. Normal EEG
B. Absence seizures
C. Myoclonic epilepsy
D. Artifacts (Correct Answer)

Explanation: ***Artifacts*** - The image displays inconsistent, **high-amplitude, irregular waveforms** across multiple channels without a clear, organized pattern suggestive of brain activity. - These patterns are typical of **muscle artifacts** or environmental interference, which are often observed in EEG recordings when there is movement, sweating, or electrical noise. *Normal EEG* - A normal EEG typically shows organized and rhythmic brainwave patterns, such as **alpha and beta rhythms**, with appropriate amplitude and frequency for the patient's state. - The chaotic and non-physiologic signals seen here do not resemble normal brain activity. *Absence seizures* - Absence seizures are characterized by **generalized 3 Hz spike-and-wave discharges** that are sudden in onset and offset and typically bilateral and synchronous. - The EEG image does not show this specific, highly characteristic epileptic pattern; instead, it shows widespread disorganized activity. *Myoclonic epilepsy* - Myoclonic epilepsy often presents with **generalized polyspike-and-wave discharges** or irregular spike-and-wave patterns, usually faster than 3 Hz, associated with sudden muscle jerks. - While there is some high-frequency activity, it lacks the clear, consistent morphology and rhythm of epileptic discharges and is more consistent with movement-related artifact.

Question 51: A 14-year-old boy presents with bilateral foot contractures. On examination, thickened peripheral nerves are noted. On biopsy of the nerve, a typical onion bulb appearance is noted. What is the probable diagnosis? (Recent NEET Pattern 2016-17)

A. Friedreich's ataxia
B. Ataxia telangiectasia
C. Charcot-Marie-Tooth disease (Correct Answer)
D. Leprosy

Explanation: ***Charcot-Marie-Tooth disease*** - The combination of **bilateral foot contractures** (often presenting as pes cavus or hammer toes, as hinted by the image), **thickened peripheral nerves**, and the pathological finding of an **onion bulb appearance** on nerve biopsy are classic diagnostic features of Charcot-Marie-Tooth (CMT) disease, particularly demyelinating forms. - CMT is a progressive **hereditary peripheral neuropathy** characterized by muscle weakness and sensory loss, primarily in the distal limbs, often leading to foot deformities. *Friedreich's ataxia* - This is a **spinocerebellar ataxia** primarily affecting the central nervous system, leading to gait ataxia, dysarthria, and scoliosis. - While it can cause foot deformities like pes cavus, it does not typically involve **thickened peripheral nerves** or the **onion bulb appearance** on nerve biopsy. *Ataxia telangiectasia* - This is a rare, **autosomal recessive disorder** characterized by progressive cerebellar ataxia, oculocutaneous telangiectasias, immunodeficiency, and an increased risk of malignancy. - It does not present with **thickened peripheral nerves** or the characteristic **onion bulb formation** on nerve biopsy. *Leprosy* - Leprosy, caused by *Mycobacterium leprae*, is an infectious disease that can affect peripheral nerves, leading to nerve thickening, sensory loss, and muscle weakness. - However, the characteristic finding on nerve biopsy in leprosy is **granulomatous inflammation** and **acid-fast bacilli**, not the **onion bulb formation** seen in hereditary demyelinating neuropathies.

Question 52: An 18-year-old patient presents with port wine stain, mental retardation and recurrent focal seizures. All are true about the condition except:

A. Optic nerve cupping
B. Tram track appearance on X-ray skull
C. Vagal nerve stimulation
D. Confetti lesions (Correct Answer)

Explanation: ***Confetti lesions*** - **Confetti lesions** (hypopigmented macules) are characteristic dermatological features of **tuberous sclerosis complex**, not Sturge-Weber syndrome. - The clinical presentation of a **port-wine stain**, mental retardation, and recurrent focal seizures is highly indicative of **Sturge-Weber syndrome**. *Optic nerve cupping* - **Glaucoma** is a common ocular complication of Sturge-Weber syndrome, often ipsilateral to the facial port-wine stain. - **Optic nerve cupping** is a finding associated with elevated intraocular pressure due to glaucoma. *Tram track appearance on X-ray skull* - The **tram track appearance** on skull X-ray or CT scan refers to **leptomeningeal angiomatosis** with underlying cortical calcifications, a hallmark of Sturge-Weber syndrome. - These calcifications follow the gyri of the brain, creating a curvilinear, double-lined pattern. *Vagal nerve stimulation* - **Vagal nerve stimulation (VNS)** is a recognized treatment option for **refractory seizures** in patients with Sturge-Weber syndrome when antiepileptic medications are insufficient. - It helps in reducing seizure frequency and severity in selected cases.

Question 53: A 35-year-old woman presents with thunderclap headache. NCCT was done. All are true about the condition except:

A. Hyponatremia
B. Prolonged QT interval
C. Most common cause of death is rebleeding (Correct Answer)
D. Nimodipine is drug of choice

Explanation: The image provided appears to be a **Non-Contrast CT (NCCT) scan of the brain**, showing a **hyperdense area** in the right hemisphere, consistent with **subarachnoid hemorrhage (SAH)** given the context of a "thunderclap headache." Thunderclap headache is a classic symptom of SAH. ***Most common cause of death is rebleeding*** - While rebleeding is a **serious complication** and contributes significantly to morbidity and mortality in SAH patients, the most common cause of death following SAH, particularly in the acute phase, is often related to the **initial hemorrhage** itself, such as **brain herniation**, or **early hydrocephalus** and **vasospasm-induced cerebral ischemia**. - **Vasospasm**, leading to **delayed cerebral ischemia (DCI)**, is a major cause of death and disability in SAH survivors, but the question asks about the "most common cause of death," which in many cases is the immediate devastating effect of the initial bleed or its early complications rather than rebleeding alone. *Hyponatremia* - **Hyponatremia** is a common electrolyte imbalance seen in patients with SAH, often due to **Syndrome of Inappropriate Antidiuretic Hormone (SIADH)** or **Cerebral Salt Wasting (CSW)**. - Therefore, the statement that hyponatremia occurs is **true** for this condition. *Prolonged QT interval* - **Cardiac abnormalities**, including **ECG changes** such as **QT prolongation**, T-wave inversion, and ST depression, are frequently observed after SAH due to **autonomic nervous system dysfunction** and catecholamine release. - Therefore, the presence of a prolonged QT interval is **true** for this condition. *Nimodipine is drug of choice* - **Nimodipine** is a **calcium channel blocker** widely used in SAH patients to **prevent or reduce the severity of cerebral vasospasm** and associated delayed cerebral ischemia. - It is currently the **drug of choice** for this indication in SAH, making this statement **true**.

Question 54: A 60-year-old man presents with history of memory loss and fatigue. On examination, he has bradykinesia with axial rigidity. Resting tremor is absent and patient has broad-based gait with tendency to fall. MRI was done. All are true about the condition except:

A. Poor response to levodopa
B. Gaze palsy
C. Humming Bird appearance
D. Intracranial hypotension (Correct Answer)

Explanation: ***Intracranial hypotension*** - Progressive Supranuclear Palsy (PSP) is characterized by **brain atrophy**, not intracranial hypotension, and specifically shows atrophy of the **midbrain** and superior cerebellar peduncle. - Intracranial hypotension typically presents with **postural headaches**, which were not mentioned in the patient's presentation. *Poor response to levodopa* - Patients with PSP often show a **poor or transient response to levodopa**, which distinguishes it from Parkinson's disease. - This is due to the widespread neurodegeneration affecting areas beyond the dopaminergic pathways. *Gaze palsy* - **Vertical supranuclear gaze palsy**, particularly affecting downward gaze, is a **hallmark symptom** of PSP. - This manifests as difficulty moving the eyes voluntarily, especially downwards, while reflex eye movements (e.g., vestibulo-ocular reflex) may be preserved initially. *Humming Bird appearance* - The **Hummingbird sign (or Penguin sign)** is a characteristic MRI finding in PSP, referring to the **midbrain atrophy** with relative preservation of the pons, resembling a hummingbird. - The image provided shows significant midbrain atrophy, consistent with this sign.

Question 55: MRI was performed on a 35-year-old man with progressive myoclonus and apathy. What is the diagnosis? (Recent NEET Pattern 2016-17)

A. Herpes simplex encephalitis
B. SSPE
C. Mesial temporal sclerosis
D. Prion disease (Correct Answer)

Explanation: ***Prion disease*** - The MRI shows **cortical ribboning** (hyperintensity in the cortex) and possible signal changes in the basal ganglia, which are characteristic findings in prion diseases such as **Creutzfeldt-Jakob disease (CJD)**. - The clinical presentation of **progressive myoclonus** (sudden, involuntary muscle jerks) and **apathy** (lack of emotion or motivation), especially in a relatively young individual (35 years old), is highly suggestive of CJD or another prion disease. *Herpes simplex encephalitis* - This typically presents with **fever, headache, and focal neurological deficits**, often affecting the **temporal lobes**. - While it can cause FLAIR hyperintensities, it usually begins acutely with more prominent edema and may have hemorrhagic components, and myoclonus is not a primary defining symptom. *SSPE* - **Subacute sclerosing panencephalitis (SSPE)** is a rare, fatal, progressive brain disorder caused by the **measles virus**, primarily affecting children and young adults. - While it can cause progressive neurological deterioration and cognitive decline, myoclonus is often a late feature, and MRI findings often show **white matter demyelination** in later stages, which is not the predominant finding here. *Mesial temporal sclerosis* - This condition is characterized by **atrophy and signal changes in the hippocampus and amygdala** on MRI, typically associated with **temporal lobe epilepsy**. - While it can cause cognitive issues, it usually does not account for widespread cortical ribboning or prominent myoclonus in this age group, and the image does not specifically highlight mesial temporal lobe changes.

Question 56: A 30-year-old patient has suffered from multiple episodes of GTCS for the last one week. MRI was performed. All are true about the condition except:

A. Steroids must be given in the racemose form (Correct Answer)
B. MRI shows colloidal stage of NCC
C. CSF eosinophilia
D. Enzyme-linked immune-electrotransfer blot assay is more sensitive than CSF ELISA

Explanation: ***Steroids must be given in the racemose form*** - The **racemose form** of neurocysticercosis (NCC) specifically refers to cysticerci growing in clusters within the subarachnoid space, often **without a scolex, and can be difficult to treat due to their inflammatory nature and location. Systemic steroids** would likely be indicated for significant cerebral edema and inflammation, but they are not *mandatory* and their efficacy in directly improving the racemose form itself is limited or unproven, nor are they a specific treatment for the racemose form, but rather used to manage inflammation. - The image provided shows a solitary, enhancing lesion, more consistent with a parenchymal cyst at the **colloidal vesicular stage**, not the racemose form. *MRI shows colloidal stage of NCC* - The MRI image displays a **ring-enhancing lesion with perifocal edema**, which is characteristic of the **colloidal vesicular stage** of neurocysticercosis. In this stage, the larva starts to degenerate, triggering a significant inflammatory response. - The central high signal intensity represents the degenerating scolex or colloidal fluid, and the surrounding low signal is indicative of extensive vasogenic edema, which can lead to seizures like the GTCS described. *CSF eosinophilia* - **CSF eosinophilia** (presence of eosinophils in cerebrospinal fluid) is a common finding in neurocysticercosis, especially when the cysts are located in the subarachnoid space or ventricles, or when there is significant inflammation. - The immune response against the parasite often involves eosinophils, making their presence in the CSF a supportive diagnostic indicator. *Enzyme-linked immune-electrotransfer blot assay is more sensitive than CSF ELISA* - The **Enzyme-linked immune-electrotransfer blot (EITB) assay** (Western blot) is considered the **gold standard** for serodiagnosis of neurocysticercosis due to its high **sensitivity (nearly 100%) and specificity (nearly 100%)**, particularly for patients with active lesions and viable cysts. - While **CSF ELISA** can detect antibodies, it generally has **lower sensitivity** compared to EITB, especially when only a single brain lesion is present, or in the very early or late calcified stages of the disease.

Question 57: A middle-aged patient presents with history of left sided weakness for 2 days. Currently the patient is extremely drowsy and underwent a NCCT brain. Which of the following is the best treatment for this patient? (AIIMS Nov 2017)

A. Aspirin/Clopidogrel
B. Mechanical thrombectomy
C. Mannitol
D. Decompressive surgery (Correct Answer)

Explanation: ***Decompressive surgery*** - The NCCT image shows a **large, well-demarcated hypodensity in the right cerebral hemisphere**, characteristic of a **subacute to chronic ischemic infarct with significant edema and mass effect**. This is evidenced by the effaced sulci, compressed ventricles on the right, and likely midline shift, causing the patient's **drowsiness** and **left-sided weakness**. - Given the patient's **drowsiness** (indicating rising intracranial pressure) and significant mass effect from the large infarct, **decompressive craniectomy** is often a life-saving measure to reduce intractable intracranial pressure and prevent further herniation in cases of malignant middle cerebral artery (MCA) infarction. *Aspirin/Clopidogrel* - These are **antiplatelet medications used for secondary stroke prevention** after an acute ischemic event. - They are not the primary treatment for an **existing large infarct with mass effect and neurological deterioration** (drowsiness), as they do not address the acute intracranial pressure. *Mechanical thrombectomy* - This procedure is indicated for **acute ischemic stroke due to large vessel occlusion**, typically performed within a very narrow time window (usually up to 6-24 hours) from symptom onset. - The patient presents two days after symptom onset, and the CT findings suggest a **subacute to chronic infarct that has completed evolution**, making thrombectomy ineffective and potentially harmful. *Mannitol* - Mannitol is an **osmotic diuretic used to acutely reduce intracranial pressure (ICP)** in situations like cerebral edema. - While it can provide temporary relief, it is often insufficient for profound edema and mass effect from a **large, evolving infarct** that is causing significant neurological decline (drowsiness), and it does not treat the underlying structural issue.

Question 58: All are true about the mid brain stroke syndrome shown except:

A. Dorsal midbrain lesion
B. Anterior cerebral peduncle is involved (Correct Answer)
C. Contralateral tremor and ataxia
D. Red nucleus involvement causes movement disorders

Explanation: ***Anterior cerebral peduncle is involved*** - The **anterior cerebral peduncle (crus cerebri)** is located in the **ventral midbrain** and contains descending motor tracts, but the lesion shown affects the **dorsal midbrain structures**. - This statement is **false** because the lesion does not extend to involve the anterior cerebral peduncle, making this the correct answer for the "except" question. *Dorsal midbrain lesion* - The image clearly shows a lesion in the **dorsal aspect of the midbrain**, affecting structures such as the **red nucleus** and surrounding areas. - This statement is **true** as it accurately describes the anatomical location of the stroke shown in the image. *Ipsilateral 3rd nerve palsy* - **Weber's syndrome** (ventral midbrain stroke) commonly presents with ipsilateral 3rd nerve palsy, and some dorsal midbrain lesions can extend to affect **oculomotor nerve fascicles**. - This statement is **true** as 3rd nerve palsy can occur with midbrain strokes, particularly when the lesion affects nerve pathways in the midbrain. *Contralateral hemiplegia* - Midbrain strokes can cause **contralateral weakness** through involvement of **corticospinal tract fibers** that pass through or near the affected area. - This statement is **true** as motor deficits are commonly seen in midbrain stroke syndromes, even with dorsal lesions that may affect descending motor connections.

Question 59: The CSF electrophoresis of patient shows oligoclonal bands. Which of the following is associated.

A. CNS leukemia
B. Monoclonal gammopathy of unknown significance
C. Multiple sclerosis (Correct Answer)
D. Multiple myeloma

Explanation: ***Multiple sclerosis*** - The presence of **oligoclonal bands** in the CSF, but not in the plasma, indicates intrathecal IgG production, which is a hallmark of **multiple sclerosis**. - These bands represent a restricted number of **B cell clones** producing immunoglobulins within the central nervous system, consistent with the immune-mediated demyelination seen in MS. *CNS leukemia* - While CNS leukemia can involve the CSF, it typically presents with **malignant cells** in the CSF and not specifically with oligoclonal bands. - The primary diagnostic finding would be abnormal cell morphology or flow cytometry detecting leukemic cells. *Monoclonal gammopathy of unknown significance* - This condition involves the presence of a **monoclonal protein (M-protein)** in the blood (plasma), but it does not typically involve intrathecal synthesis of oligoclonal bands in the CSF. - The M-protein is usually detected in serum protein electrophoresis, not CSF. *Multiple myeloma* - Multiple myeloma is a plasma cell malignancy characterized by a **monoclonal protein** in the serum and/or urine, and sometimes in the CSF if there is CNS involvement. - However, the CSF findings in multiple myeloma would typically show the presence of the same monoclonal protein found in the serum, rather than distinct oligoclonal bands specific to the CNS.

Question 60: In the ECG tracing shown below, which of the following is correct?

A. First degree AV block, intranodal
B. Second degree AV block type 1, intranodal (Correct Answer)
C. Second degree AV block type 2, infranodal
D. Second degree AV block type 2, intranodal

Explanation: ***Second degree AV block type 1, intranodal*** - The ECG shows **progressive lengthening of the PR interval** with each successive beat, followed by a **dropped QRS complex**, a classic pattern for Mobitz I (Wenckebach) AV block. - Mobitz I block is almost always due to a physiological delay within the **AV node (intranodal)**. *First degree AV block, intranodal* - First-degree AV block is characterized by a **constant, prolonged PR interval** (>0.20 seconds) without any dropped QRS complexes. - While it can be intranodal, the key feature of a dropped beat after progressive PR lengthening is absent here. *Second degree AV block type 2, infranodal* - Second degree AV block type 2 (Mobitz II) involves a **constant PR interval** for conducted beats, but with intermittent, **unheralded dropped QRS complexes**. - Mobitz II is typically due to disease in the **His-Purkinje system (infranodal)** and carries a higher risk of progression to complete heart block. *Second degree AV block type 2, intranodal* - Second-degree AV block type 2 is characterized by a **constant PR interval** with intermittently dropped beats. - While Mobitz II is usually infranodal, the hallmark of progressive PR lengthening seen in the tracing rules out Mobitz II entirely.

Question 61: A 65-year-old man loses consciousness at a Newyear party. On admission heart rate is 50 / min and BP is 170 / 110 mm Hg. JVP is normal. S2 is normal split and chest is bilaterally clear. The medic shows you his ECG. Troponin I value is <0.04 ng / dL. GCS is 7. Comment on the diagnosis.

A. STEMI
B. Stroke (Correct Answer)
C. Hyperkalemia
D. Stokes-Adams syndrome

Explanation: ***Stroke*** - The combination of **altered consciousness (GCS 7)**, **hypertension (BP 170/110 mmHg)**, and **bradycardia (HR 50/min)** in an elderly patient losing consciousness abruptly is highly suggestive of **Cushing's triad**, which is a sign of increased intracranial pressure often due to a stroke. - The **normal JVP and clear chest** rule out acute heart failure or pulmonary edema, and the **normal troponin I** rules out an acute myocardial infarction as the primary event. The provided ECG is essentially normal, lacking signs of acute ischemia or severe electrolyte disturbances. *STEMI* - An **ST-elevation myocardial infarction (STEMI)** would typically present with chest pain (though silent MIs can occur), and the ECG would show significant **ST-segment elevation** in at least two contiguous leads. - The patient's **troponin I is normal (<0.04 ng/dL)**, making STEMI very unlikely. *Hyperkalemia* - **Hyperkalemia** on ECG typically manifests as **tall, peaked T waves**, prolonged PR interval, wide QRS, and eventually sine wave patterns or asystole. - The provided ECG does not show these characteristic findings, rendering hyperkalemia an improbable primary diagnosis. *Stokes-Adams syndrome* - **Stokes-Adams syndrome** is characterized by recurrent syncopal attacks caused by transient **bradyarrhythmias or asystole** due to advanced AV block or sick sinus syndrome. - While the patient has bradycardia, there is no evidence of advanced AV block or asystole on the provided ECG, and the primary presentation points more strongly towards a neurological event.

Question 62: The most common cause of pontine hemorrhage is

A. Hypertension (Correct Answer)
B. Diabetes
C. Trauma
D. Aneurysmal rupture

Explanation: Hypertension - **Chronic hypertension** leads to the weakening and rupture of small perforating arteries in the pons, making it the most common cause of **pontine hemorrhage** [1]. - The elevated pressure damages the **endothelium** and smooth muscle layers of these vessels, predisposing them to bleeding. *Diabetes* - While diabetes can cause microvascular complications, it is not considered the most common cause of **pontine hemorrhage**. - Its primary cerebral vascular complications include increased risk of **ischemic stroke** rather than hemorrhagic stroke in the pons. *Trauma* - **Traumatic brain injury** can cause various types of intracranial hemorrhage, but isolated **pontine hemorrhage** directly due to trauma is less common than that due to hypertension [1]. - Trauma typically results in contusions, subdural, or epidural hematomas, often in superficial brain regions. *Aneurysmal rupture* - **Aneurysmal rupture** is a common cause of subarachnoid hemorrhage, particularly from the Circle of Willis, but pontine hemorrhages are rarely caused by aneurysms within the pons itself [1]. - The vessels supplying the pons are typically small and perforating, not commonly forming dissecting or saccular aneurysms.

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