PANRE Neurology 4 — Questions and Answers
Question 1: A 62-year-old man with hypertension develops sudden left-sided weakness and slurred speech that resolves completely in 45 minutes. Workup includes ECG showing atrial fibrillation. Best long-term stroke prevention strategy?
- Aspirin alone
- Clopidogrel plus aspirin
- Anticoagulation with a DOAC (Correct answer)
- Carotid endarterectomy
Correct answer: Anticoagulation with a DOAC
Atrial fibrillation-related TIA requires anticoagulation (preferably a DOAC) to prevent cardioembolic stroke; antiplatelet therapy is insufficient for this indication.
Question 2: A 25-year-old woman has episodes of muscle weakness triggered by rest after exercise and is improved by eating. Potassium level is low during attacks. Diagnosis?
- Hypokalemic periodic paralysis (Correct answer)
- Lambert-Eaton myasthenic syndrome
- Myotonic dystrophy
- Paramyotonia congenita
Correct answer: Hypokalemic periodic paralysis
Hypokalemic periodic paralysis is characterized by episodic weakness with low serum potassium, often triggered by rest after exercise or carbohydrate-rich meals.
Question 3: Which imaging finding is pathognomonic for diffuse axonal injury after traumatic brain injury?
- Midline shift on CT
- Petechial hemorrhages at gray-white junction on MRI (Correct answer)
- Hyperdense subdural collection
- Cerebral edema on CT
Correct answer: Petechial hemorrhages at gray-white junction on MRI
Diffuse axonal injury is best seen on MRI as petechial hemorrhages or signal changes at the gray-white matter junction, corpus callosum, and brainstem from rotational shear forces.
Question 4: A patient on isoniazid therapy develops peripheral neuropathy. Which supplement is deficient?
- Vitamin B12
- Vitamin B6 (pyridoxine) (Correct answer)
- Folate
- Vitamin D
Correct answer: Vitamin B6 (pyridoxine)
Isoniazid competitively inhibits pyridoxine (B6) metabolism, causing a sensory-predominant peripheral neuropathy that is prevented by B6 supplementation.
Question 5: A 70-year-old man presents with urinary incontinence, gait apraxia, and cognitive decline. MRI shows enlarged ventricles disproportionate to sulcal atrophy. Treatment?
- Acetylcholinesterase inhibitor
- Ventriculoperitoneal shunt (Correct answer)
- Levodopa/carbidopa
- High-dose steroids
Correct answer: Ventriculoperitoneal shunt
The triad of gait apraxia, cognitive decline, and urinary incontinence with disproportionate ventriculomegaly is normal pressure hydrocephalus, treated with VP shunt placement.
Question 6: A patient develops a foot drop after total hip replacement surgery. The most likely nerve injured is:
- Femoral nerve
- Obturator nerve
- Common peroneal (fibular) nerve
- Sciatic nerve (Correct answer)
Correct answer: Sciatic nerve
Sciatic nerve injury is the most common neurological complication of hip replacement surgery, and foot drop can result from the peroneal division of the sciatic nerve being most vulnerable.
Question 7: Which test is most sensitive for detecting early Alzheimer disease when clinical diagnosis is uncertain?
- EEG
- FDG-PET showing temporal-parietal hypometabolism
- MRI showing hippocampal atrophy
- CSF tau/amyloid ratio (Correct answer)
Correct answer: CSF tau/amyloid ratio
CSF analysis showing elevated phosphorylated tau and reduced amyloid-beta 42 (or the tau/Aβ42 ratio) is the most sensitive and specific biomarker for early Alzheimer disease.
PANRE Neurology 4
A 62-year-old man with hypertension develops sudden left-sided weakness and slurred speech that resolves completely in 45 minutes.
Workup includes ECG showing atrial fibrillation.
Best long-term stroke prevention strategy?