MD Central Nervous System Disorders 4 — Questions and Answers
Question 1: A 35-year-old woman presents with episodic unilateral headache, nausea, photophobia, and phonophobia lasting 4-72 hours. She notes visual aura preceding attacks. What is the classification?
- Cluster headache
- Migraine with aura (Correct answer)
- Tension-type headache
- Trigeminal neuralgia
Correct answer: Migraine with aura
Recurrent unilateral headache with nausea, photophobia, and preceding visual aura fulfills criteria for migraine with aura.
Question 2: A patient with longstanding type 2 diabetes presents with distal symmetric burning pain and loss of vibration sense in the feet. Which pathway is primarily damaged?
- Anterior spinothalamic tract
- Dorsal columns and small unmyelinated C-fibers (Correct answer)
- Corticospinal tract
- Spinocerebellar tract
Correct answer: Dorsal columns and small unmyelinated C-fibers
Diabetic peripheral neuropathy affects both small fibers (pain/temperature, C-fibers) and large fibers (vibration, dorsal column) in a length-dependent pattern.
Question 3: A 65-year-old smoker presents with proximal limb weakness that improves with repeated muscle use. Reflexes are absent but return after exercise. What antibody mediates this condition?
- Anti-AChR
- Anti-voltage-gated calcium channel (VGCC) (Correct answer)
- Anti-MuSK
- Anti-GQ1b
Correct answer: Anti-voltage-gated calcium channel (VGCC)
Lambert-Eaton myasthenic syndrome is caused by anti-VGCC antibodies that reduce presynaptic acetylcholine release, often paraneoplastic with SCLC.
Question 4: A 28-year-old presents with subacute confusion, psychiatric symptoms, orofacial dyskinesias, and CSF showing mild pleocytosis. What is the most likely diagnosis?
- Herpes simplex encephalitis
- Anti-NMDA receptor encephalitis (Correct answer)
- Tuberculous meningitis
- Syphilitic meningitis
Correct answer: Anti-NMDA receptor encephalitis
Anti-NMDA receptor encephalitis classically presents in young women with psychiatric prodrome, dyskinesias, autonomic instability, and CSF pleocytosis.
Question 5: Which of the following is the mechanism of action of memantine in Alzheimer disease?
- Acetylcholinesterase inhibition
- NMDA receptor antagonism (Correct answer)
- Beta-secretase inhibition
- Tau aggregation inhibition
Correct answer: NMDA receptor antagonism
Memantine is an NMDA receptor antagonist that reduces excitotoxic glutamate signaling, approved for moderate-to-severe Alzheimer disease.
Question 6: A 45-year-old with history of alcohol abuse presents with confusion, ophthalmoplegia, and ataxia. What should be administered immediately?
- Glucose bolus
- Thiamine IV before glucose (Correct answer)
- Naloxone IV
- Lorazepam IV
Correct answer: Thiamine IV before glucose
Thiamine must be given before glucose to prevent precipitating Wernicke encephalopathy in thiamine-deficient patients.
Question 7: A 55-year-old presents with ipsilateral Horner syndrome, contralateral pain/temperature loss, ipsilateral facial numbness, dysphagia, and hoarseness. Which artery is occluded?
- Basilar artery
- Posterior inferior cerebellar artery (Correct answer)
- Anterior spinal artery
- Middle cerebral artery
Correct answer: Posterior inferior cerebellar artery
Lateral medullary (Wallenberg) syndrome results from PICA occlusion and presents with the described crossed sensory deficit and cranial nerve findings.
MD Central Nervous System Disorders 4
A 35-year-old woman presents with episodic unilateral headache, nausea, photophobia, and phonophobia lasting 4-72 hours.
She notes visual aura preceding attacks.
What is the classification?