Neurology Practice Questions

Q: What is the most common cranial mononeuropathy in diabetic patients?

Facial nerve (VII). The correct answer is **Facial nerve (VII)**. While many students mistakenly prioritize the extraocular nerves, epidemiological studies and clinical data consistently show that **Bell’s Palsy (Facial nerve palsy)** is the most common cranial mononeuropathy in patients with diabetes mellitus [1]. Diabetic patients have a significantly higher risk (up to 25% higher) of developing facial nerve palsy compared to the general population due to microvascular ischemia of the nerve. **Analysis of Options:** * **Facial nerve (VII):** The most frequent cranial nerve involved. It typically presents as lower motor neuron facial weakness [1]. * **Oculomotor nerve (III):** This is the most common **extraocular** cranial nerve affected. A classic NEET-PG high-yield point is that diabetic CN III palsy is **"pupil-sparing"** because the parasympathetic fibers are located superficially and receive a separate blood supply, while the central motor fibers suffer ischemic damage. * **Abducens nerve (VI):** The second most common extraocular nerve affected. It presents with horizontal diplopia and an inability to abduct the eye. * **Optic nerve (II):** While diabetes causes retinopathy, it does not typically cause a "mononeuropathy" of the optic nerve in the same acute ischemic sense as the motor nerves. **Clinical Pearls for NEET-PG:** 1. **Rule of Thumb:** If the question asks for the most common *cranial nerve* overall, choose **CN VII**. If it asks for the most common *extraocular* nerve, choose **CN III**. 2. **Pupillary Sparing:** Always remember that diabetic CN III palsy spares the pupil, whereas a compressive lesion (like a PCom artery aneurysm) involves the pupil. 3. **Pathophysiology:** The primary mechanism for diabetic mononeuropathies is **vasa nervorum ischemia** (microvascular disease) [2]. 4. **Prognosis:** Most diabetic cranial mononeuropathies have a good prognosis, with spontaneous recovery usually occurring within 3–6 months [1].

Q: A 45-year-old male presents with hypertension and sudden abnormal flinging movements in his right upper and lower limbs. What is the most likely site of hemorrhage?

Subthalamic nuclei. **Explanation:** The clinical presentation of sudden-onset, large-amplitude, violent, and flinging movements of the limbs on one side of the body is characteristic of **Hemiballismus** [1]. **1. Why Subthalamic Nucleus (STN) is correct:** Hemiballismus most commonly results from a lesion (usually hemorrhagic or ischemic stroke) in the **contralateral subthalamic nucleus of Luys** [1]. The STN normally provides excitatory (glutamatergic) input to the globus pallidus interna (GPi), which in turn inhibits the thalamus [2]. A lesion in the STN reduces this inhibition, leading to an overactive motor cortex and the characteristic hyperkinetic movements [2]. **2. Why other options are incorrect:** * **Substantia Nigra:** Degeneration here leads to **Parkinsonism** (bradykinesia, tremors, and rigidity) due to dopamine deficiency, rather than hyperkinetic flinging movements [3]. * **Caudate Nuclei:** Lesions here (as seen in Huntington’s disease) typically present with **Chorea**—brief, semi-directed, irregular movements—rather than the violent flinging seen in ballismus [1]. * **Pons:** Pontine hemorrhages usually present with "pinpoint pupils," quadriplegia, and coma; they do not cause isolated hemiballismus. **Clinical Pearls for NEET-PG:** * **Most common cause:** Lacunar stroke (infarction or hemorrhage) secondary to hypertension or diabetes [1]. * **Laterality:** The movement is always **contralateral** to the side of the lesion [1]. * **Anatomy:** The STN is part of the **indirect pathway** of the basal ganglia. Loss of the indirect pathway results in hyperkinesia [2].

Q: Sudden onset of hemiplegia with contralateral ophthalmoplegia indicates a probable lesion in which of the following locations?

Mesencephalon. This clinical presentation describes a **crossed hemiplegia** (ipsilateral cranial nerve palsy with contralateral motor deficit), which is the hallmark of a brainstem lesion. [1] ### **Explanation of the Correct Answer** The combination of **ipsilateral ophthalmoplegia** (3rd Cranial Nerve palsy) and **contralateral hemiplegia** is known as **Weber Syndrome**. * **Location:** The lesion is in the **Mesencephalon (Midbrain)**, specifically involving the ventromedial aspect. * **Structures involved:** It affects the exiting fibers of the **Oculomotor nerve (CN III)**, causing ipsilateral ptosis and a "down and out" eye, and the **Cerebral Peduncle (Corticospinal tract)**, causing contralateral hemiplegia. [2] ### **Analysis of Incorrect Options** * **A. Pons:** Lesions here typically present with **Millard-Gubler Syndrome**, characterized by contralateral hemiplegia and ipsilateral **6th (Abducens)** or **7th (Facial)** nerve palsies. * **B. Lateral Medulla:** This results in **Wallenberg Syndrome**. It typically presents with sensory deficits (loss of pain/temperature), ataxia, and dysphagia, but notably **spares the corticospinal tract**, so hemiplegia is absent. * **D. Forebrain:** A cortical or internal capsule lesion would cause **unilateral** deficits (hemiplegia and cranial nerve deficits on the *same* side), not the "crossed" pattern seen in brainstem strokes. ### **NEET-PG High-Yield Pearls** * **Weber Syndrome:** Midbrain + CN III palsy + Contralateral Hemiplegia. * **Benedikt Syndrome:** Midbrain + CN III palsy + Contralateral Tremor/Ataxia (Red Nucleus involvement). * **Rule of 4s:** Cranial nerves 3 and 4 are in the Midbrain; 5, 6, 7, and 8 are in the Pons; 9, 10, 11, and 12 are in the Medulla. * **Crossed signs** (Face on one side, body on the other) always point to the **Brainstem**.

Q: A 70-year-old man presents with an acute disturbance of vision and balance. He reports sudden onset of vertigo while seated, followed by dizziness and unsteadiness upon attempting to ambulate. Examination reveals nystagmus and a left homonymous hemianopia. His blood pressure is 170/80 mmHg, with other vital signs normal. An MRI head shows an acute ischemic infarct. According to the Bamford classification, what type of stroke has this patient suffered?

Posterior circulation stroke (POCS). ### Explanation The patient has suffered a **Posterior Circulation Stroke (POCS)**. The Bamford (Oxford) Classification categorizes strokes based on clinical presentation to predict the site of infarction and prognosis. **Why POCS is the correct answer:** POCS involves the territory supplied by the vertebrobasilar system (brainstem, cerebellum, and occipital lobes). This patient presents with classic "posterior" signs: 1. **Cerebellar/Brainstem signs:** Vertigo, nystagmus, and ataxia (unsteadiness) [1]. 2. **Isolated Visual Field Defect:** Left homonymous hemianopia indicates an infarct in the right occipital lobe (supplied by the Posterior Cerebral Artery) [1]. According to Bamford criteria, POCS is diagnosed if the patient presents with any of the following: brainstem/cerebellar dysfunction, isolated homonymous hemianopia, or conjugate eye movement disorders. **Why other options are incorrect:** * **TACS (Total Anterior Circulation Stroke):** Requires a triad of: (1) Hemiparesis/Hemisensory loss, (2) Homonymous hemianopia, and (3) Higher cortical dysfunction (e.g., Aphasia or Neglect) [2]. This patient lacks motor deficits and cortical signs. * **PACS (Partial Anterior Circulation Stroke):** Requires only 2 out of the 3 TACS criteria, or isolated higher cortical dysfunction. * **LACS (Lacunar Stroke):** Presents as pure motor, pure sensory, or ataxic hemiparesis. It **never** presents with visual field defects or higher cortical dysfunction. **NEET-PG High-Yield Pearls:** * **Bamford Classification** is purely clinical and does not require imaging for categorization. * **TACS** has the worst prognosis and is usually due to a large MCA territory infarct. * **Homonymous hemianopia** can occur in both TACS and POCS. To differentiate: if it occurs with motor/sensory loss, think TACS; if it occurs in isolation, think POCS. * **Vertigo + Nystagmus + Ataxia** = Vertebrobasilar (Posterior) territory [1].

Q: A 19-year-old female complains of worsening facial pain for the past 1 week. She describes it as an intense shooting pain that comes and goes, and it is only present on her right face. Which of the following is most likely to be this patient’s underlying problem?

Multiple sclerosis. The patient presents with classic features of **Trigeminal Neuralgia (TN)**: intense, paroxysmal, shooting pain localized to the distribution of the trigeminal nerve. While TN is most commonly caused by vascular compression of the nerve root in older adults, its occurrence in a **young patient (19 years old)** is a major red flag for **Multiple Sclerosis (MS)** [1]. In MS, demyelination within the brainstem (specifically the trigeminal nerve entry zone) leads to ephaptic transmission (cross-talk) between axons, triggering neuralgic pain. For NEET-PG, remember: **Bilateral trigeminal neuralgia or TN in a young patient is MS until proven otherwise.** **Analysis of Incorrect Options:** * **A. Tolosa-Hunt Syndrome:** Characterized by painful ophthalmoplegia (eye movement palsy) due to idiopathic granulomatous inflammation of the cavernous sinus. It involves cranial nerves III, IV, and VI, not just isolated V. * **B. Migraine:** Presents as a throbbing, unilateral headache often associated with photophobia and nausea, rather than brief, lancinating "shooting" facial pain [2]. * **D. Anterior Communicating Artery Aneurysm:** Typically presents with a sudden "thunderclap" headache (Subarachnoid Hemorrhage) or visual field defects [2]. It does not cause isolated trigeminal neuralgia. (Note: Posterior communicating artery aneurysms typically cause CN III palsy). **Clinical Pearls for NEET-PG:** * **Drug of Choice for TN:** Carbamazepine. * **Lhermitte’s Sign:** An electric shock-like sensation down the spine on neck flexion; highly characteristic of MS. * **Charcot’s Triad (MS):** Nystagmus, Intention tremor, and Scanning speech. * **Investigation of Choice:** MRI with gadolinium (to look for demyelinating plaques) [1].

Q: Which of the following is NOT a feature of corticospinal tract involvement?

Cog-wheel rigidity. The **Corticospinal tract (CST)** is the primary Upper Motor Neuron (UMN) pathway responsible for voluntary motor control. Lesions involving the CST result in a **UMN syndrome**, characterized by a loss of inhibitory control over spinal reflexes. ### Why Cog-wheel Rigidity is the Correct Answer **Cog-wheel rigidity** is a hallmark of **Extrapyramidal system** involvement (specifically the Basal Ganglia), not the Corticospinal tract. It is typically seen in Parkinson’s disease and results from a combination of lead-pipe rigidity and a resting tremor. Unlike UMN lesions, extrapyramidal lesions do not typically cause weakness or changes in deep tendon reflexes. ### Explanation of Incorrect Options (Features of CST Lesions) * **Spasticity:** This is a velocity-dependent increase in muscle tone (clasp-knife type) seen in UMN lesions due to the loss of descending inhibition on the gamma motor neurons. * **Plantar extensor response (Babinski sign):** This is the most reliable sign of a CST lesion. In adults, the normal response is flexor; an extensor response indicates damage to the pyramidal tract. * **Exaggerated deep tendon reflexes (Hyperreflexia):** Damage to the CST removes the inhibitory influence on the monosynaptic stretch reflex arc, leading to brisk reflexes and potentially clonus. ### High-Yield Clinical Pearls for NEET-PG * **Pyramidal vs. Extrapyramidal:** Pyramidal (CST) lesions cause **spasticity** (clasp-knife, velocity-dependent), while Extrapyramidal (Basal Ganglia) lesions cause **rigidity** (lead-pipe or cog-wheel, uniform throughout movement). * **UMN vs. LMN:** UMN lesions show hyperreflexia and hypertonia; Lower Motor Neuron (LMN) lesions show atrophy, fasciculations, and hyporeflexia. * **The "Rule of Thumb":** If the question mentions "Babinski sign" or "Clasp-knife," think Corticospinal Tract. If it mentions "Tremor" or "Cog-wheel," think Basal Ganglia.

Question 1

What is the most common cranial mononeuropathy in diabetic patients?

Accepted Answer

Facial nerve (VII)

Answer

Optic nerve (II)

Answer

Oculomotor nerve (III)

Answer

Abducens nerve (VI)

Question 2

A 45-year-old male presents with hypertension and sudden abnormal flinging movements in his right upper and lower limbs. What is the most likely site of hemorrhage?

Accepted Answer

Subthalamic nuclei

Answer

Substantia nigra

Answer

Caudate nuclei

Answer

Pons

Question 3

Sudden onset of hemiplegia with contralateral ophthalmoplegia indicates a probable lesion in which of the following locations?

Accepted Answer

Mesencephalon

Answer

Pons

Answer

Lateral medulla

Answer

Forebrain

Question 4

A 70-year-old man presents with an acute disturbance of vision and balance. He reports sudden onset of vertigo while seated, followed by dizziness and unsteadiness upon attempting to ambulate. Examination reveals nystagmus and a left homonymous hemianopia. His blood pressure is 170/80 mmHg, with other vital signs normal. An MRI head shows an acute ischemic infarct. According to the Bamford classification, what type of stroke has this patient suffered?

Accepted Answer

Posterior circulation stroke (POCS)

Answer

Lacunar stroke (LACS)

Answer

Partial anterior circulation stroke (PACS)

Answer

Total anterior circulation stroke (TACS)

Question 5

A 19-year-old female complains of worsening facial pain for the past 1 week. She describes it as an intense shooting pain that comes and goes, and it is only present on her right face. Which of the following is most likely to be this patient’s underlying problem?

Accepted Answer

Multiple sclerosis

Answer

Tolosa-Hunt syndrome

Answer

Migraine

Answer

Anterior communicating artery aneurysm

Question 6

A 25-year-old male presents with intermittent diplopia, urinary incontinence, and VI nerve palsy. What is the most likely diagnosis?

Accepted Answer

Multiple sclerosis

Answer

Acute infarct

Answer

Intraparenchymal bleed

Answer

Alzheimer's disease

Question 7

Which of the following is NOT a feature of corticospinal tract involvement?

Accepted Answer

Cog-wheel rigidity

Answer

Spasticity

Answer

Plantar extensor response

Answer

Exaggerated deep tendon reflexes

Question 8

Which of the following is a cause of reversible dementia?

Accepted Answer

Subacute combined degeneration.

Answer

Picks disease.

Answer

Creutzfeldt-Jakob disease.

Answer

Alzheimer's disease.

Question 9

What distinguishes cervical transverse myelitis with spinal shock from Guillain-Barré syndrome?

Accepted Answer

A sharp level of demarcation of sensory and motor symptoms exists.

Answer

Hypotonia is present.

Answer

Decreased stretch and superficial reflexes are observed.

Answer

Absent neuropathic pain occurs.

Question 10

A 50-year-old male patient presents to the emergency department with right hemiparesis and loss of speech for 2.5 hours. His blood pressure is 180/100 mmHg. What is the next best step in the management of this patient?

Accepted Answer

Perform non-contrast computed tomography (NCCT) of the brain

Answer

Administer antihypertensives to control blood pressure

Answer

Administer aspirin and anticoagulants

Answer

Administer tissue plasminogen activator

Neurology — MCQs

Neurology — MCQs

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