Which of the following sites is responsible for the amnestic defect in Wernicke's Korsakoff syndrome:
Which of the following is the most common initial presenting feature of multiple sclerosis:
What are the expected neurological manifestations in a patient with complete absence of the corpus callosum?
Which of the following is the MOST characteristic feature of Eaton-Lambert syndrome?
What is the first symptom of Parkinson's disease?
Isaac syndrome is characterized by -
Most common acute complication of dialysis is
What is the most common cause of death in patients with advanced cancer?
All of the following are true about Gout, except which of the following?
Most common organism associated with reactive arthritis is:
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 111: Which of the following sites is responsible for the amnestic defect in Wernicke's Korsakoff syndrome:
- A. Hippocampus
- B. Mammillary body
- C. Thalamus (Correct Answer)
- D. Periventricular Grey matter
Explanation: ***Thalamus*** - Damage to the **medial dorsal nucleus of the thalamus** is a key pathological finding in Wernicke's Korsakoff syndrome, directly contributing to the severe **anterograde and retrograde amnesia** [1]. - The thalamus plays a crucial role in memory consolidation and retrieval, acting as a relay station for information processing between cortical and subcortical structures. *Mammillary body* - While **mammillary body damage** is characteristic of Wernicke-Korsakoff syndrome, it is primarily associated with the **acute Wernicke encephalopathy phase** and contributes to the overall amnesia through its connections with the thalamus and hippocampus, rather than being the sole site for the amnestic defect [1]. - The mammillary bodies are part of the **Papez circuit**, which is important for episodic memory, but their lesion alone doesn't fully explain the complete amnestic syndrome. *Hippocampus* - The **hippocampus** is critical for the formation of new memories, and its damage typically causes **anterograde amnesia**, as seen in conditions like temporal lobe epilepsy or anoxia. - While memory is affected, direct **hippocampal lesions are not the primary pathology** in Wernicke-Korsakoff syndrome; the memory impairment arises from damage to structures *connected* to the hippocampus, such as the thalamus and mammillary bodies. *Periventricular Grey matter* - The **periventricular grey matter** is involved in various autonomic functions and pain modulation, not directly in memory formation or retrieval. - While lesions in this area can occur in Wernicke-Korsakoff syndrome, they are not considered the primary cause of the **amnestic defect**.
Question 112: Which of the following is the most common initial presenting feature of multiple sclerosis:
- A. Optic Neuritis (Correct Answer)
- B. Cerebellar Ataxia
- C. Internuclear ophthalmoplegia
- D. Diplopia
Explanation: ***Optic Neuritis*** - **Optic neuritis** is a very common initial symptom of multiple sclerosis, occurring in 20-25% of patients. - It presents with **unilateral vision loss** (often painful), blurred vision, and a central scotoma, reflecting inflammation and demyelination of the optic nerve [1]. *Cerebellar Ataxia* - While **cerebellar ataxia** (impaired coordination, balance, speech) can occur in MS, it is less common as an initial presenting symptom. - It often develops later in the disease course due to demyelination in the **cerebellum** or its connections [1]. *Internuclear ophthalmoplegia* - **Internuclear ophthalmoplegia (INO)** is a specific eye movement disorder common in MS but rarely the very first symptom [1]. - It results from a lesion in the **medial longitudinal fasciculus (MLF)**, causing impaired adduction of one eye during conjugate gaze with nystagmus in the abducting eye. *Diplopia* - **Diplopia** (double vision) can be an early symptom of MS, but it is less frequent as the very first presentation compared to optic neuritis [1]. - It typically arises from lesions affecting the **cranial nerves** controlling eye movements (III, IV, VI) or their brainstem nuclei.
Question 113: What are the expected neurological manifestations in a patient with complete absence of the corpus callosum?
- A. Mild cognitive impairment
- B. Seizures
- C. No significant neurological deficits
- D. Severe developmental delays (Correct Answer)
Explanation: ***Severe developmental delays*** - Complete agenesis of the corpus callosum often results in **significant neurological impairments** due to the disruption of interhemispheric communication essential for coordinated brain function. - This typically manifests as **intellectual disability**, **developmental delays** in motor and speech skills, and difficulties with complex cognitive tasks. *Mild cognitive impairment* - While some individuals with partial agenesis or isolated cases might present with mild cognitive issues, **complete absence** usually leads to more profound deficits. - Mild impairment would not fully capture the extensive neurological challenges associated with a total lack of such a critical brain structure. *Seizures* - Seizures can occur in patients with corpus callosum agenesis, but they are not the **most encompassing** or universally expected neurological manifestation. - Seizures are often part of a broader syndrome of developmental abnormalities rather than the primary expected outcome of the agenesis itself. *No significant neurological deficits* - The corpus callosum is vital for **integrating information** between the cerebral hemispheres, affecting a wide range of sensory, motor, and cognitive functions. - Therefore, its complete absence almost invariably leads to notable neurological deficits, making a lack of significant issues highly unlikely.
Question 114: Which of the following is the MOST characteristic feature of Eaton-Lambert syndrome?
- A. Repeated electrical stimulation enhances muscle power in it. (Correct Answer)
- B. Neostigmine is not effective for this syndrome.
- C. It is commonly associated with small cell lung cancer.
- D. It can affect the ocular muscles.
Explanation: ***Repeated electrical stimulation enhances muscle power in it.*** - A hallmark feature of **Lambert-Eaton Myasthenic Syndrome (LEMS)** is the **potentiation of muscle strength** with repeated or high-frequency nerve stimulation [2]. - This is due to the disease pathophysiology where repeated stimulation allows the accumulation of **intracellular calcium**, leading to increased acetylcholine release at the neuromuscular junction. *Neostigmine is not effective for this syndrome.* - While it's largely true that **acetylcholinesterase inhibitors** like neostigmine are less effective in LEMS compared to myasthenia gravis, they can still provide some minor symptomatic relief [1]. - Therefore, stating it's *not effective* might be an oversimplification, and it's not the *most characteristic* feature. *It is commonly associated with small cell lung cancer.* - Although LEMS is frequently a **paraneoplastic syndrome** linked to **small cell lung cancer (SCLC)**, this association is a cause/etiology, not a direct characteristic feature of the neuromuscular dysfunction itself [1], [2]. - Approximately 50-60% of LEMS cases are paraneoplastic, with SCLC being the most common underlying malignancy [2]. *It can affect the ocular muscles.* - **Ocular muscle involvement** (e.g., ptosis, diplopia) is a prominent and often initial symptom in **myasthenia gravis** [2]. - In LEMS, ocular muscle weakness is **much less common** and typically mild, if present, distinguishing it from myasthenia gravis.
Question 115: What is the first symptom of Parkinson's disease?
- A. Rigidity
- B. Tremors (Correct Answer)
- C. Postural instability
- D. Bradykinesia
Explanation: ***Tremors*** - A resting **tremor**, often starting unilaterally in a hand or foot, is frequently the **initial motor symptom** of Parkinson's disease [1]. - This tremor is typically **slow**, rhythmic, and may involve a "pill-rolling" motion of the fingers [1]. *Postural instability* - **Postural instability** tends to be a later symptom, emerging as the disease progresses and affecting balance and gait [2]. - It is not usually the **presenting complaint** in the early stages of Parkinson's disease [2]. *Rigidity* - **Rigidity**, characterized by increased muscle tone and resistance to passive movement, often develops after tremors or bradykinesia [1]. - It can manifest as **cogwheel** or **lead-pipe rigidity** and contributes to the stooped posture and reduced arm swing observed in Parkinson's patients [1]. *Bradykinesia* - **Bradykinesia** (slowness of movement) is a core motor symptom, often described as difficulty initiating or continuing movements [1]. - While present early, **tremors** are often the first symptom noticed by the patient or their family, making bradykinesia a close second in sequence [1].
Question 116: Isaac syndrome is characterized by -
- A. Peripheral nerve hyperexcitability (Correct Answer)
- B. Opsoclonus syndrome
- C. Encephalitis
- D. Limbic encephalitis syndrome
Explanation: Isaac syndrome is characterized by - ***Peripheral nerve hyperexcitability*** - Isaac syndrome, also known as **neuromyotonia** or **Isaacs' syndrome**, is fundamentally characterized by symptoms arising from **peripheral nerve hyperexcitability**. [1] - This hyperexcitability leads to continuous muscle fiber activity even at rest, manifesting as **muscle stiffness, cramps, myokymia, and fasciculations**. *Opsoclonus syndrome* - This syndrome is characterized by **rapid, irregular, chaotic eye movements** (**opsoclonus**) and often associated with **myoclonus (rapid muscle jerks)** and **ataxia (impaired coordination)**. - While it can be paraneoplastic, it involves the **central nervous system**, specifically the brainstem and cerebellum, not primarily peripheral nerve hyperexcitability. *Encephalitis* - **Encephalitis** is an inflammation of the **brain parenchyma**, typically caused by viral infections. - Its clinical presentation includes fever, headache, altered mental status, and seizures, which are distinct from the primary neuromuscular symptoms of Isaac syndrome. *Limbic encephalitis syndrome* - **Limbic encephalitis** is a form of encephalitis specifically affecting the **limbic system** of the brain, leading to symptoms like **memory loss, seizures, and psychiatric disturbances**. - This condition involves **central nervous system inflammation** and does not directly cause the peripheral nerve hyperexcitability seen in Isaac syndrome.
Question 117: Most common acute complication of dialysis is
- A. Hypotension (Correct Answer)
- B. Bleeding
- C. Dementia
- D. Muscle cramps
Explanation: ***Hypotension*** - **Intradialytic hypotension** is the most common acute complication, occurring in 15-30% of dialysis sessions. - It is often caused by rapid removal of fluid (ultrafiltration), leading to a significant drop in blood pressure [1]. *Bleeding* - While bleeding can occur due to **anticoagulation** used during dialysis or as a complication of vascular access, it is less common than hypotension. - It is not considered the most frequent acute complication of the dialysis procedure itself. *Dementia* - **Dementia** is a chronic neurological condition that is not an acute complication directly attributable to a single dialysis session. - It can be a long-term comorbidity in patients with end-stage renal disease (ESRD), but not an immediate side effect. *Muscle cramps* - **Muscle cramps** are a relatively common acute complication during or immediately after dialysis, affecting about 5-20% of patients. - However, their frequency is generally lower than that of intradialytic hypotension [1].
Question 118: What is the most common cause of death in patients with advanced cancer?
- A. Bleeding
- B. Infection (Correct Answer)
- C. Respiratory failure
- D. Renal failure
Explanation: ***Infection*** - **Immunosuppression** from cancer itself and its treatments (e.g., chemotherapy, radiation) significantly increases susceptibility to infections. - Many patients with advanced cancer die from **sepsis** or opportunistic infections due to their weakened immune systems [1]. *Bleeding* - While bleeding can be a significant complication in advanced cancer (e.g., from tumor erosion, thrombocytopenia), it is less common as a direct cause of death compared to infection. - Life-threatening hemorrhages are typically managed, and other factors often contribute to mortality. *Respiratory failure* - **Respiratory failure** can occur due to **lung metastases**, direct tumor invasion, or complications like pneumonia in advanced cancer patients. - However, the underlying cause of such pneumonia or decline is often infectious or a result of systemic weakness. *Renal failure* - **Renal failure** can be caused by tumor obstruction of the urinary tract, **nephrotoxic chemotherapy**, or paraneoplastic syndromes. - Although serious, it is not the most frequent immediate cause of death in the broad population of advanced cancer patients.
Question 119: All of the following are true about Gout, except which of the following?
- A. Can be precipitated by pyrazinamide
- B. Birefringent crystals are present in the joint
- C. Occurs due to accumulation of urate crystals in joint
- D. Occurs more in females (Correct Answer)
Explanation: ***Occurs more in females*** - **Gout** is more prevalent in **males** than in females, especially before menopause, due to hormonal differences and lifestyle factors. - After menopause, the incidence in females increases but generally remains lower than in males. *Occurs due to accumulation of urate crystals in joint* - **Gout** is precisely characterized by the **deposition of monosodium urate crystals** in joints and surrounding tissues, leading to inflammation [1], [2]. - This accumulation is a direct consequence of **hyperuricemia**, either from overproduction or underexcretion of uric acid [2], [3]. *Can be precipitated by pyrazinamide* - **Pyrazinamide** is an anti-tuberculosis drug known to **inhibit uric acid excretion** by the kidneys. - This leads to **hyperuricemia**, thereby increasing the risk of acute gout attacks. *Birefringent crystals are present in the joint* - Microscopic examination of **synovial fluid** from a gouty joint reveals **needle-shaped, negatively birefringent crystals** of monosodium urate [1], [4]. - This finding is a definitive diagnostic criterion for **gout**.
Question 120: Most common organism associated with reactive arthritis is:
- A. Staphylococcus
- B. Shigella
- C. Chlamydia (Correct Answer)
- D. Yersinia
Explanation: ***Chlamydia*** - **Chlamydia trachomatis** is a commonly identified pathogen causing **genitourinary infections** that can trigger reactive arthritis [1]. - The organism itself is not present in the joint, but its antigens trigger an immune response leading to sterile arthritis [1]. *Staphylococcus* - **Staphylococcus aureus** is a common cause of septic arthritis, which involves direct bacterial invasion of the joint. - Reactive arthritis is a **sterile arthritis** triggered by an infection elsewhere, not directly caused by staphylococcal joint infection. *Shigella* - While **Shigella** is a known enteric pathogen that can trigger reactive arthritis, it is less commonly associated with the condition globally compared to Chlamydia [1]. - Reactive arthritis often follows episodes of **dysentery** caused by Shigella species [1]. *Yersinia* - **Yersinia enterocolitica** is another enteric bacterium that can induce reactive arthritis, typically after **gastrointestinal infections**. - Its prevalence as a trigger for reactive arthritis is generally lower than that of Chlamydia.