Neurology Practice Questions

Q: Which condition presents with normal nerve conduction studies but exhibits flaccidity?

Myasthenia gravis. The clinical presentation of **flaccidity** (lower motor neuron type weakness) with **normal nerve conduction studies (NCS)** is a hallmark of disorders affecting the neuromuscular junction (NMJ) or the muscle itself, rather than the peripheral nerves [4]. 1. **Why Myasthenia Gravis (MG) is correct:** MG is an autoimmune disorder caused by antibodies against acetylcholine receptors at the NMJ [2], [3]. Since the pathology is at the synapse and not the nerve axon or myelin, a **standard NCS** (which measures the speed and amplitude of an impulse along a nerve) remains **normal**. To diagnose MG electrophysiologically, one must perform a **Repetitive Nerve Stimulation (RNS)** test, which shows a decremental response. 2. **Why other options are incorrect:** * **Guillain-Barré Syndrome (GBS):** This is a demyelinating polyradiculoneuropathy. NCS will be **abnormal**, typically showing prolonged F-wave latencies, slowed conduction velocities, or conduction blocks. * **Transverse Myelitis:** This is an upper motor neuron (UMN) lesion of the spinal cord. While it can cause "spinal shock" (temporary flaccidity), the NCS remains normal; however, the clinical context involves sensory levels and bladder involvement, which are absent in MG. * **Traumatic Neuritis:** Direct injury to a nerve causes axonal damage or demyelination, leading to **abnormal NCS** findings (reduced CMAP amplitude or slowing) in the distribution of that nerve [1]. **NEET-PG High-Yield Pearls:** * **NCS vs. RNS:** Standard NCS is normal in MG; **Repetitive Nerve Stimulation (RNS)** is the specific test (showing >10% decrement). * **Ice Pack Test:** A simple bedside test for MG; cold improves neuromuscular transmission and reduces ptosis. * **Pure Motor:** MG presents with fluctuating weakness and ptosis/diplopia but **never** involves sensory loss or loss of autonomic function [3].

Q: III nerve palsy associated with contralateral hemiplegia is known as which syndrome?

Weber's syndrome. ### Explanation **Weber’s Syndrome** is a classic brainstem stroke syndrome involving the **ventral (anterior) midbrain**. It occurs due to an occlusion of the paramedian branches of the posterior cerebral artery. 1. **Why Option A is Correct:** The lesion involves two key structures in the midbrain: * **Fascicles of the Oculomotor Nerve (III):** Results in **ipsilateral** III nerve palsy (ptosis, "down and out" eye, and dilated pupil) [1]. * **Cerebral Peduncle (Corticospinal & Corticobulbar tracts):** Results in **contralateral** hemiplegia of the body and lower face. The combination of ipsilateral cranial nerve deficit and contralateral motor deficit is termed "crossed hemiplegia." 2. **Why Other Options are Incorrect:** * **Benedikt’s Syndrome:** Involves the **tegmentum** of the midbrain. It affects the III nerve and the **Red Nucleus**, leading to ipsilateral III nerve palsy combined with contralateral tremors/chorea (extrapyramidal signs), rather than pure hemiplegia. * **Claude’s Syndrome:** A more posterior midbrain lesion affecting the III nerve and the **Superior Cerebellar Peduncle**, resulting in ipsilateral III nerve palsy and contralateral **ataxia**. * **Avellis Syndrome:** A medullary syndrome (not midbrain) involving the Nucleus Ambiguus and Spinothalamic tract, causing paralysis of the soft palate/larynx and contralateral loss of pain/temperature. ### High-Yield Clinical Pearls for NEET-PG: * **Site of Lesion:** Ventral Midbrain. * **Vessel Involved:** Paramedian branches of the Posterior Cerebral Artery (PCA). * **Rule of 4s:** Remember that CN III and IV are in the midbrain. Any syndrome involving CN III must be a midbrain lesion. * **Mnemonic for Midbrain Syndromes:** * **W**eber = **W**heels (Cerebral peduncle/Motor). * **B**enedikt = **B**allistic (Red nucleus/Tremors). * **C**laude = **C**erebellar (Ataxia).

Q: What is a characteristic feature of subcortical dementia?

Memory loss. **Explanation:** Dementia is broadly classified into **cortical** and **subcortical** types based on the primary site of pathology. **Why Memory Loss is correct:** Memory loss is a core feature of all dementias, including subcortical dementia. However, the *nature* of the memory deficit differs. In subcortical dementia (e.g., Parkinson’s disease, Huntington’s disease, Wilson’s disease, or Multi-infarct dementia), the primary issue is **retrieval failure** rather than an inability to encode new information. Patients often benefit from cues or recognition tasks, unlike cortical dementia (e.g., Alzheimer’s), where there is a failure of storage/encoding. Other hallmark features of subcortical dementia include **psychomotor slowing (bradyphrenia)**, executive dysfunction, and personality changes (apathy/depression). **Why the other options are incorrect:** * **B, C, and D (Aphasia, Dyslexia, Tactile Agnosia):** These are considered **"Cortical Signs."** They represent the "4 As" (Amnesia, Aphasia, Apraxia, Agnosia) typically seen in cortical dementias like Alzheimer’s Disease. * **Aphasia:** Language impairment due to cortical damage (Broca’s/Wernicke’s areas). * **Dyslexia:** Difficulty reading, often linked to the parietal-temporal cortex. * **Tactile Agnosia:** Inability to recognize objects by touch, indicating parietal lobe dysfunction. **High-Yield NEET-PG Pearls:** * **Cortical Dementia:** Alzheimer’s, Pick’s Disease. Features: Early aphasia, agnosia, and severe memory storage loss. * **Subcortical Dementia:** Parkinson’s, Huntington’s, Progressive Supranuclear Palsy (PSP). Features: "Forgetfulness" (retrieval issue), slowed thinking, and prominent motor symptoms. * **Key Differentiator:** If a question mentions "aphasia" or "apraxia," think **Cortical**. If it mentions "psychomotor slowing" or "movement disorders," think **Subcortical**.

Q: Hypokalemic periodic paralysis is inherited as an autosomal dominant disorder with incomplete penetrance. It is caused by a mutation in which of the following channels?

Calcium channel. **Explanation:** **Hypokalemic Periodic Paralysis (HOKPP)** is the most common form of periodic paralysis [1]. It is characterized by episodic muscle weakness triggered by factors that lower serum potassium levels, such as high-carbohydrate meals or strenuous exercise [1]. **Why the Correct Answer is Right:** The primary defect in **Type 1 HOKPP** (accounting for ~70% of cases) is a mutation in the **CACNA1S gene**, which encodes the **α1-subunit of the L-type voltage-gated calcium channel** (Dihydropyridine receptor) in skeletal muscle. This mutation results in an aberrant "gating pore current" that leads to muscle membrane depolarization and inexcitability during periods of low extracellular potassium. **Analysis of Incorrect Options:** * **A. Sodium channel:** Mutations in the **SCN4A** gene (Sodium channel) cause **Hyperkalemic** Periodic Paralysis [1]. While a small subset of HOKPP (Type 2) is caused by sodium channel mutations, the classic and most frequent association taught for exams is the calcium channel. * **B. Potassium channel:** Mutations in potassium channels (e.g., KCNJ2) are associated with **Andersen-Tawil Syndrome**, which presents with periodic paralysis, cardiac arrhythmias (long QT), and skeletal abnormalities. * **C. Chloride channel:** Mutations in the **CLCN1** chloride channel cause **Myotonia Congenita** (Thomsen and Becker diseases), characterized by delayed muscle relaxation rather than episodic paralysis [1]. **Clinical Pearls for NEET-PG:** * **Triggers:** High carb intake (insulin shifts K+ intracellularly), rest after exercise, and stress [1]. * **Treatment:** Acute attacks are treated with oral/IV Potassium. Prophylaxis involves **Acetazolamide** (carbonic anhydrase inhibitor) or potassium-sparing diuretics. * **Thyrotoxic Periodic Paralysis:** A common differential in Asian males; it presents identically to HOKPP but is associated with hyperthyroidism.

Q: What is the typical presentation of a Wernicke's aphasia lesion?

Fluent speech with meaningless content. **Explanation:** Wernicke’s aphasia, also known as **Sensory or Receptive Aphasia**, results from a lesion in the posterior part of the superior temporal gyrus (Brodmann area 22) of the dominant hemisphere. **1. Why Option B is Correct:** In Wernicke’s aphasia, the motor ability to produce speech remains intact, but the **comprehension of language** is lost. Patients exhibit "fluent" speech—meaning the rate, rhythm, and articulation are normal—but the content is "meaningless." This is often described as **"word salad"** or jargon aphasia, where the patient uses neologisms (made-up words) and paraphasias (word substitutions) without realizing their speech lacks sense. **2. Why Other Options are Incorrect:** * **Option A:** Fluent speech with meaningful content describes normal, healthy communication. * **Option C:** Non-fluent speech with meaningful content is the hallmark of **Broca’s Aphasia** (Motor Aphasia). These patients struggle to produce words (telegraphic speech) but understand what is being said to them. * **Option D:** Non-fluent speech with meaningless content is characteristic of **Global Aphasia**, where both Broca’s and Wernicke’s areas (and the arcuate fasciculus) are damaged. **Clinical Pearls for NEET-PG:** * **Anatomical Site:** Posterior Superior Temporal Gyrus (supplied by the inferior division of the Middle Cerebral Artery). * **Key Feature:** Patients are typically **unaware** of their deficit (anosognosia), unlike Broca’s patients who are often frustrated. * **Conduction Aphasia:** If the **Arcuate Fasciculus** (the connection between Broca’s and Wernicke’s) is damaged, the patient has fluent speech and good comprehension but **impaired repetition**. * **Memory Trick:** **W**ernicke’s = **W**ord Salad; **B**roca’s = **B**roken speech.

Q: All are true about Miller Fisher syndrome except?

Muscle weakness. **Miller Fisher Syndrome (MFS)** is a rare, localized variant of **Guillain-Barré Syndrome (GBS)**. It is classically defined by a clinical triad, and understanding this triad is the key to solving this question. ### Why "Muscle Weakness" is the Correct Answer Unlike the classic form of GBS (Acute Inflammatory Demyelinating Polyradiculoneuropathy), which presents with prominent ascending paralysis and limb weakness, **Miller Fisher Syndrome typically spares the limb muscles.** While patients may feel "unsteady," this is due to sensory ataxia rather than motor loss. Significant limb weakness is generally absent; if it occurs, the diagnosis often shifts to an "MFS-GBS overlap syndrome." ### Explanation of Incorrect Options (The Classic Triad) The hallmark of MFS is the triad of: * **Ataxia (Option A):** Patients present with a profound gait ataxia. This is sensory in nature, caused by the involvement of large-diameter sensory fibers. * **Areflexia (Option B):** There is a generalized loss of deep tendon reflexes, similar to classic GBS, due to peripheral nerve involvement. * **Ophthalmoplegia (Option D):** This is often the presenting feature. It manifests as external ophthalmoplegia (paralysis of eye muscles), frequently starting with diplopia. ### High-Yield Clinical Pearls for NEET-PG * **Antibody Marker:** The most specific marker for MFS is the **Anti-GQ1b antibody** (present in >90% of cases). These antibodies target gangliosides highly concentrated in the oculomotor nerves and muscle spindles. * **Preceding Infection:** Like GBS, it often follows a respiratory or gastrointestinal infection (commonly *Campylobacter jejuni*). * **CSF Findings:** Shows **albuminocytologic dissociation** (elevated protein with a normal cell count), though this may be absent in the first week. * **Prognosis:** Generally carries a good prognosis with spontaneous recovery over weeks to months. Treatment (IVIG or Plasmapheresis) is similar to GBS.

Q: A patient with traumatic paraplegia due to injury of the thoracic cord at T3 level is observed to have a blood pressure of 210/120 mmHg. What is the initial management?

Nifedipine. **Explanation:** The patient is presenting with **Autonomic Dysreflexia (AD)**, a life-threatening medical emergency occurring in patients with spinal cord injuries at or above the **T6 level**. **1. Why Nifedipine is Correct:** Autonomic Dysreflexia is triggered by noxious stimuli (e.g., distended bladder, fecal impaction) below the level of the lesion. This causes a massive, uninhibited sympathetic discharge leading to severe hypertension, bradycardia (reflexive), and pounding headaches. The **initial management** involves sitting the patient upright (to induce orthostatic pressure drop) and identifying/removing the trigger. If blood pressure remains dangerously high (as in this case, 210/120 mmHg), rapid-acting antihypertensives are indicated. **Nifedipine (immediate-release)** or Nitroglycerin paste are the preferred agents to prevent intracranial hemorrhage or seizures. **2. Why Other Options are Incorrect:** * **A. LMWH:** Used for DVT prophylaxis in spinal cord injuries, but it does not address the acute hypertensive crisis. * **B. Steroids:** High-dose methylprednisolone was previously used for acute spinal cord injury to reduce edema, but it is no longer the standard of care due to complications and has no role in managing acute hypertension. * **D. Normal Saline/Dextrose:** Fluid resuscitation is contraindicated here as it could further worsen the hypertension and volume load. **High-Yield Clinical Pearls for NEET-PG:** * **Level of Lesion:** AD typically occurs in injuries at **T6 or above** (above the splanchnic outflow). * **Classic Triad:** Hypertension, Bradycardia, and Flushing/Sweating *above* the level of injury. * **Most Common Trigger:** Bladder distension (check the Foley catheter first!). * **Management Priority:** 1. Sit the patient up → 2. Loosen tight clothing → 3. Empty bladder/bowel → 4. Pharmacotherapy (Nifedipine) if BP >150 mmHg systolic.

Q: Examination of a patient revealed ipsilateral third nerve paresis and cerebellar ataxia. What is the MOST likely diagnosis?

Nothnagel's syndrome. **Explanation:** The clinical presentation of **ipsilateral 3rd nerve palsy** combined with **cerebellar ataxia** is the hallmark of **Nothnagel’s syndrome**. This midbrain stroke syndrome occurs due to a lesion in the **superior cerebellar peduncle** and the emerging fibers of the **oculomotor nerve (CN III)**. **Why Nothnagel’s syndrome is correct:** The lesion is typically located in the dorsal midbrain (tectum). The involvement of the superior cerebellar peduncle results in ipsilateral (or sometimes bilateral) cerebellar ataxia, while the involvement of the CN III fascicles leads to ipsilateral ophthalmoplegia and ptosis. **Analysis of Incorrect Options:** * **Weber’s Syndrome:** Characterized by ipsilateral 3rd nerve palsy and **contralateral hemiparesis** (due to involvement of the crus cerebri/pyramidal tract) [1]. * **Claude’s Syndrome:** Characterized by ipsilateral 3rd nerve palsy and **contralateral cerebellar ataxia** (due to involvement of the red nucleus and dentatothalamic tract) [1]. *Note: Nothnagel's is often distinguished by the presence of gait ataxia and its more dorsal location.* * **Benedikt’s Syndrome:** Characterized by ipsilateral 3rd nerve palsy and **contralateral tremors/involuntary movements** (chorea/athetosis) due to involvement of the red nucleus and substantia nigra. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of Thumb:** All midbrain syndromes involve the **ipsilateral 3rd nerve**. The differentiating factor is the motor/sensory deficit [1]: * **Weber:** Hemiplegia (Motor) * **Benedikt:** Tremors (Extrapyramidal) * **Claude:** Ataxia (Cerebellar) * **Nothnagel:** Ataxia + Ocular signs (often associated with pineal tumors or tectal lesions). * The most common cause of these syndromes is an infarct in the branches of the **Posterior Cerebral Artery (PCA)**.

Q: Epilepsy is defined as?

Two unprovoked seizures. The definition of epilepsy is primarily clinical and focuses on the enduring predisposition of the brain to generate spontaneous seizures [1]. According to the **International League Against Epilepsy (ILAE)**, epilepsy is defined by any of the following conditions [1]: 1. At least **two unprovoked (or reflex) seizures** occurring more than 24 hours apart. 2. One unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years. 3. Diagnosis of an epilepsy syndrome. **Why Option B is correct:** Historically and clinically, a single seizure does not constitute epilepsy. The occurrence of two unprovoked seizures signifies a permanent threshold shift, indicating a chronic neurological disorder rather than a transient insult [1]. **Why other options are incorrect:** * **Option A:** A single unprovoked seizure is termed a "provoked" or "isolated" seizure. While it requires investigation, it does not meet the criteria for epilepsy unless there is a high risk of recurrence (e.g., structural brain abnormality on MRI). * **Options C & D:** While having three or four seizures certainly confirms epilepsy, the minimum diagnostic threshold is two. Waiting for a third or fourth event would unnecessarily delay treatment. **High-Yield Clinical Pearls for NEET-PG:** * **Provoked Seizures:** These are caused by temporary factors (hypoglycemia, hyponatremia, alcohol withdrawal, or high fever) and are **not** classified as epilepsy. * **Resolved Epilepsy:** Epilepsy is considered resolved if an individual remains seizure-free for 10 years, with at least the last 5 years off anti-seizure medications. * **Status Epilepticus:** Defined as >5 minutes of continuous seizure activity or two or more discrete seizures without full recovery of consciousness between them.

Question 1

A 75-year-old woman presents with severe pain in the ear, described as if bathed in acid, and associated with emboli. What is the likely location of the lesion?

Accepted Answer

Thalamus

Answer

Pons

Answer

Temporal region

Answer

Occipital region

Question 2

Which condition presents with normal nerve conduction studies but exhibits flaccidity?

Accepted Answer

Myasthenia gravis

Answer

Guillain-Barré syndrome

Answer

Transverse myelitis

Answer

Traumatic neuritis

Question 3

III nerve palsy associated with contralateral hemiplegia is known as which syndrome?

Accepted Answer

Weber's syndrome

Answer

Benedict's syndrome

Answer

Claude's syndrome

Answer

Avellis syndrome

Question 4

What is a characteristic feature of subcortical dementia?

Accepted Answer

Memory loss

Answer

Aphasia

Answer

Dyslexia

Answer

Tactile agnosia

Question 5

Hypokalemic periodic paralysis is inherited as an autosomal dominant disorder with incomplete penetrance. It is caused by a mutation in which of the following channels?

Accepted Answer

Calcium channel

Answer

Sodium channel

Answer

Potassium channel

Answer

Chloride channel

Question 6

What is the typical presentation of a Wernicke's aphasia lesion?

Accepted Answer

Fluent speech with meaningless content

Answer

Fluent speech with meaningful content

Answer

Non-fluent speech with meaningful content

Answer

Non-fluent speech with meaningless content

Question 7

All are true about Miller Fisher syndrome except?

Accepted Answer

Muscle weakness

Answer

Ataxia

Answer

Areflexia

Answer

Ophthalmoplegia

Question 8

A patient with traumatic paraplegia due to injury of the thoracic cord at T3 level is observed to have a blood pressure of 210/120 mmHg. What is the initial management?

Accepted Answer

Nifedipine

Answer

Subcutaneous low molecular weight heparin

Answer

Steroids

Answer

Normal saline/Dextrose

Question 9

Examination of a patient revealed ipsilateral third nerve paresis and cerebellar ataxia. What is the MOST likely diagnosis?

Accepted Answer

Nothnagel's syndrome

Answer

Weber's syndrome

Answer

Claude's syndrome

Answer

Benedikt's syndrome

Question 10

Epilepsy is defined as?

Accepted Answer

Two unprovoked seizures

Answer

One unprovoked seizure

Answer

Three unprovoked seizures

Answer

Four unprovoked seizures

Neurology — MCQs

Neurology — MCQs

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