Neurology Practice Questions

Q: What is the most common physical sign of cerebral metastasis?

Focal neurological deficit. ### Explanation **Cerebral metastasis** is the most common type of intracranial tumor in adults, occurring in approximately 20–40% of cancer patients. **Why Focal Neurological Deficit is Correct:** The most common presenting **physical sign** of brain metastasis is a focal neurological deficit (found in about 50–70% of patients) [1]. This occurs because metastatic lesions are typically located at the **gray-white matter junction**, where they cause local tissue destruction, mass effect, and significant vasogenic edema [1]. Depending on the location (e.g., frontal, parietal, or temporal lobes), this manifests as hemiparesis, sensory loss, or aphasia. **Analysis of Incorrect Options:** * **A. Epilepsy (Seizures):** While common, seizures occur in only about 15–25% of patients [1]. They are more frequent in metastases involving the cortex (e.g., melanoma) but are less common than focal deficits. * **C. Papilloedema:** This is a sign of increased intracranial pressure (ICP) . While many patients suffer from headaches due to ICP, overt papilloedema is a late finding and is less frequent than specific focal deficits. * **D. Visual Defects:** These are a specific type of focal deficit (e.g., hemianopia) but are less common than motor or sensory deficits because they require specific involvement of the optic radiations or occipital cortex. **High-Yield Clinical Pearls for NEET-PG:** * **Most common primary source:** Lung cancer (most common overall), followed by Breast cancer and Melanoma. * **Most common to bleed:** Melanoma, Choriocarcinoma, Renal Cell Carcinoma (RCC), and Thyroid cancer. * **Distribution:** 80% occur in the cerebral hemispheres, 15% in the cerebellum, and 5% in the brainstem [1]. * **Imaging:** Contrast-enhanced MRI is the gold standard; lesions typically show "ring enhancement" with extensive surrounding edema [1].

Q: The triad of Wernicke's encephalopathy includes all the following except?

Visual hallucinations. **Explanation:** Wernicke’s Encephalopathy (WE) is an acute, reversible neuropsychiatric emergency caused by a deficiency of **Thiamine (Vitamin B1)**, most commonly seen in chronic alcoholics. The diagnosis is primarily clinical and is defined by a classic **triad**: 1. **Ophthalmoplegia (Option C):** Characterized by ocular signs, most commonly horizontal nystagmus and bilateral abducens (6th nerve) palsy. 2. **Ataxia (Option B):** Primarily affecting gait and stance due to cerebellar involvement. 3. **Global Confusion (Option A):** An encephalopathy characterized by disorientation, apathy, and decreased consciousness. **Visual Hallucinations (Option D)** is the correct answer because it is **not** part of the Wernicke triad. Visual hallucinations are typically associated with **Alcohol Withdrawal Delirium (Delirium Tremens)** or Alcoholic Hallucinosis, rather than acute thiamine deficiency. **High-Yield Clinical Pearls for NEET-PG:** * **Pathology:** The most characteristic lesions are found in the **mammillary bodies**, periaqueductal gray matter, and the floor of the fourth ventricle. * **Korsakoff Psychosis:** If WE is untreated, it can progress to Korsakoff syndrome, characterized by **anterograde amnesia** and **confabulation** (filling memory gaps with fabricated stories). * **Management Rule:** Always administer **Thiamine before Glucose** in a malnourished or alcoholic patient. Giving glucose first can precipitate or worsen WE by consuming the remaining thiamine stores during carbohydrate metabolism. * **MRI Finding:** Increased T2/FLAIR signal intensity in the mammillary bodies is a highly specific finding.

Q: An 18-year-old male presents with inability to walk, with rapidly evolving weakness affecting his legs and feet starting 2 days prior. Physical examination reveals inability to move his feet or ankles and difficulty raising his thighs off the bed. He has symmetrical hyporeflexia of the legs, and his sensorium is intact. He was treated 10 days previously for an upper respiratory tract infection. The immunological response producing the patient's symptoms is most intense at which of the following locations?

Spinal motor nerves. **Explanation:** The clinical presentation of rapidly evolving, symmetrical ascending weakness, hyporeflexia, and a preceding respiratory infection (10 days prior) is classic for **Guillain-Barré Syndrome (GBS)**, specifically the Acute Inflammatory Demyelinating Polyradiculoneuropathy (AIDP) subtype [1]. **1. Why the Correct Answer is Right:** GBS is an immune-mediated demyelinating polyneuropathy. The underlying mechanism is **molecular mimicry**, where antibodies against pathogens (like *C. jejuni* or respiratory viruses) cross-react with gangliosides on the myelin sheath or axons of the **peripheral nerves and spinal nerve roots** [1]. The inflammatory infiltrate and demyelination are most intense at the level of the **spinal motor nerves** (nerve roots), leading to the characteristic Lower Motor Neuron (LMN) signs like flaccidity and hyporeflexia [2]. **2. Why Incorrect Options are Wrong:** * **A & C (Lateral corticospinal tracts / Precentral gyrus):** These are components of the Upper Motor Neuron (UMN) system. UMN lesions present with hyperreflexia and spasticity, whereas this patient has hyporeflexia [2]. * **B (Neuromuscular junction):** This is the site of pathology for Myasthenia Gravis or Lambert-Eaton Syndrome. These typically present with fluctuating weakness (fatigability) or ocular symptoms, rather than an acute, ascending paralysis following an infection. **High-Yield Clinical Pearls for NEET-PG:** * **Most common antecedent infection:** *Campylobacter jejuni* (associated with the AMAN variant). * **CSF Finding:** **Albuminocytologic dissociation** (High protein with normal cell count). * **Treatment:** Intravenous Immunoglobulin (IVIG) or Plasmapheresis. **Steroids are not effective.** * **Prognostic Indicator:** Vital capacity monitoring is crucial to detect impending respiratory failure [1].

Q: Ocular bobbing is seen in which type of brain damage?

Pontine damage. **Explanation:** **Ocular bobbing** is a classic clinical sign characterized by a rapid downward jerk of the eyes followed by a slow drift back to the primary position. **Why Pontine Damage is Correct:** Ocular bobbing is a highly specific localizing sign for **acute destructive lesions of the pons**, most commonly a large pontine hemorrhage, infarct, or tumor. The physiological mechanism involves the destruction of the horizontal gaze centers (Paramedian Pontine Reticular Formation - PPRF) in the pons. When horizontal eye movements are abolished, vertical movements (which are mediated by the midbrain) persist but become dysregulated, resulting in the characteristic "bobbing" motion [2]. **Analysis of Incorrect Options:** * **Midbrain damage:** Lesions here typically cause vertical gaze palsies (e.g., Parinaud syndrome) rather than bobbing. In fact, for ocular bobbing to occur, the midbrain must be relatively intact to facilitate the vertical eye movement [2]. * **Medulla damage:** Medullary lesions are associated with different types of nystagmus (like downbeat nystagmus) or Wallenberg syndrome, but not classic ocular bobbing. * **Cerebellum damage:** While large cerebellar masses can cause bobbing, they do so indirectly by compressing the underlying pons [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Ocular Dipping:** Slow downward movement followed by a fast upward flick (the reverse of bobbing); usually seen in **anoxic encephalopathy**. * **Inverse Bobbing (Ocular Tucking):** Fast upward movement followed by a slow downward drift. * **Localization:** If you see "Bobbing," think **Pons**. If you see "Downbeat Nystagmus," think **Craniovertebral junction** (e.g., Arnold-Chiari malformation). * Ocular bobbing is typically seen in **comatose patients** where spontaneous horizontal eye movements are absent.

Q: Which type of aphasia affects the arcuate fasciculus?

Conduction aphasia. **Explanation:** The correct answer is **Conduction Aphasia**. **1. Why Conduction Aphasia is correct:** Conduction aphasia is caused by a lesion in the **arcuate fasciculus**, the white matter tract that connects Wernicke’s area (sensory speech) to Broca’s area (motor speech). Because the connection between understanding and production is severed, the hallmark clinical feature is **severely impaired repetition**. Patients have fluent speech and intact comprehension but cannot repeat phrases spoken to them. **2. Why the other options are incorrect:** * **Global Aphasia:** Results from large lesions affecting both Broca’s and Wernicke’s areas (often due to total MCA territory infarcts). It involves a complete loss of all language functions (fluency, comprehension, and repetition). * **Anomic Aphasia:** Characterized by difficulty in word-finding (naming objects). It is the mildest form of aphasia and lacks a specific localized lesion, though it is often associated with the angular gyrus. * **Broca’s Aphasia:** Caused by a lesion in the posterior part of the inferior frontal gyrus (Brodmann areas 44, 45). It is a non-fluent aphasia where comprehension is preserved, but speech production is effortful and "telegraphic." **3. NEET-PG High-Yield Clinical Pearls:** * **Repetition is the key:** If repetition is **impaired**, the lesion is "perisylvian" (Broca, Wernicke, or Conduction). If repetition is **preserved**, the lesion is "transcortical." * **Paraphasic errors:** Patients with conduction aphasia often demonstrate "phonemic paraphasias" (substituting similar-sounding words) and frequent self-correction attempts (*conduit d'approche*). * **Vascular Supply:** Most aphasias involve the **Left Middle Cerebral Artery (MCA)**. Conduction aphasia specifically involves the division of the MCA supplying the supramarginal gyrus.

Q: Which of the following tests is not useful for the diagnosis of patients with Ocular Myasthenia Gravis?

Spirometry. **Explanation:** The diagnosis of **Ocular Myasthenia Gravis (OMG)** focuses on confirming neuromuscular junction dysfunction localized to the extraocular and levator muscles. **Why Spirometry is the correct answer:** Spirometry is used to assess pulmonary function (forced vital capacity) in patients with **Generalized Myasthenia Gravis** to monitor for respiratory muscle weakness or an impending myasthenic crisis. In purely **Ocular Myasthenia**, the pathology is restricted to the eyes (ptosis and diplopia); therefore, spirometry provides no diagnostic value for the ocular subtype. **Analysis of other options:** * **MRI Brain:** While not a test for Myasthenia itself, it is **essential for the differential diagnosis** of OMG. It helps rule out compressive lesions (like third nerve palsy or brainstem tumors) that mimic ocular symptoms. * **Anti-MuSK Antibody Titer:** This is a specific serological test. While more common in generalized MG, a subset of seronegative (AChR-negative) patients may test positive for MuSK antibodies. * **Ice Pack Test:** A highly sensitive bedside test for OMG. Cooling the eyelid inhibits acetylcholinesterase, increasing acetylcholine availability and temporarily improving ptosis. **Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Single Fiber EMG (SFEMG) is the most sensitive test. * **Most Specific Serology:** Anti-AChR antibodies (though often negative in 50% of OMG cases). * **Simpson’s Test:** Sustained upward gaze leading to worsening ptosis (fatigability). * **Cogan’s Lid Twitch:** Brief overshoot of the upper lid when shifting from downgaze to primary position. * **Associated Condition:** Always screen for **Thymoma** using a CT Chest in newly diagnosed MG patients.

Question 1

What is the most common physical sign of cerebral metastasis?

Accepted Answer

Focal neurological deficit

Answer

Epilepsy

Answer

Papilloedema

Answer

Visual defects

Question 2

A pregnant patient presents with right-sided hemiparesis and aphasia for over 1 hour. A CT scan of the brain is normal. What is the next best step in management?

Accepted Answer

Thrombolysis

Answer

Dual antiplatelet therapy immediately

Answer

Perform MRI and catheter-guided clot extraction

Answer

Perform thrombectomy

Question 3

The triad of Wernicke's encephalopathy includes all the following except?

Accepted Answer

Visual hallucinations

Answer

Global confusion

Answer

Ataxia

Answer

Ophthalmoplegia

Question 4

An 18-year-old male presents with inability to walk, with rapidly evolving weakness affecting his legs and feet starting 2 days prior. Physical examination reveals inability to move his feet or ankles and difficulty raising his thighs off the bed. He has symmetrical hyporeflexia of the legs, and his sensorium is intact. He was treated 10 days previously for an upper respiratory tract infection. The immunological response producing the patient's symptoms is most intense at which of the following locations?

Accepted Answer

Spinal motor nerves

Answer

Lateral corticospinal tracts

Answer

Neuromuscular junction

Answer

Precentral gyrus

Question 5

Ocular bobbing is seen in which type of brain damage?

Accepted Answer

Pontine damage

Answer

Midbrain damage

Answer

Medulla damage

Answer

Cerebellum damage

Question 6

Diagnosis of Myasthenia gravis is typically done by using which of the following tests?

Accepted Answer

Edrophonium test

Answer

Neostigmine test

Answer

Succinylcholine administration

Answer

Atropine challenge

Question 7

Arrange the following drugs in sequence of their use in status epilepticus: Phenytoin, Lorazepam, Phenobarbital, Propofol?

Accepted Answer

Lorazepam > Phenytoin > Phenobarbital > Propofol

Answer

Phenytoin > Lorazepam > Phenobarbital > Propofol

Answer

Lorazepam > Phenobarbital > Propofol > Phenytoin

Answer

Phenobarbital > Phenytoin > Propofol > Lorazepam

Question 8

Which type of aphasia affects the arcuate fasciculus?

Accepted Answer

Conduction aphasia

Answer

Global aphasia

Answer

Anomic aphasia

Answer

Broca's aphasia

Question 9

Palinopsia is seen in occlusion of:

Accepted Answer

P2 Posterior cerebral artery

Answer

M1 Middle cerebral artery

Answer

M2 Middle cerebral artery

Answer

P1 Posterior cerebral artery

Question 10

Which of the following tests is not useful for the diagnosis of patients with Ocular Myasthenia Gravis?

Accepted Answer

Spirometry

Answer

MRI Brain

Answer

Anti MUSK antibody titer

Answer

Ice pack test

Neurology — MCQs

Neurology — MCQs

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