MD Central Nervous System Disorders 5 — Questions and Answers
Question 1: A 22-year-old college student presents with fever, severe headache, photophobia, and neck stiffness. CSF shows WBC 2,000 (90% PMNs), low glucose, high protein. What is empiric treatment?
- Acyclovir alone
- Ceftriaxone + vancomycin + dexamethasone (Correct answer)
- Amphotericin B
- Doxycycline
Correct answer: Ceftriaxone + vancomycin + dexamethasone
Bacterial meningitis is treated empirically with ceftriaxone plus vancomycin (for resistant pneumococcus) and dexamethasone to reduce inflammation.
Question 2: A patient on warfarin presents with headache, confusion, and a hyperdense crescent-shaped lesion over the convexity on non-contrast CT. What is the diagnosis?
- Epidural hematoma
- Subdural hematoma (Correct answer)
- Subarachnoid hemorrhage
- Intracerebral hemorrhage
Correct answer: Subdural hematoma
A crescent-shaped hyperdense collection crossing suture lines over the brain convexity is the classic appearance of an acute subdural hematoma.
Question 3: A 70-year-old presents with acute painless monocular vision loss described as a curtain falling over the eye, lasting 10 minutes then resolving. What does this represent?
- Retinal detachment
- Amaurosis fugax (transient monocular blindness) (Correct answer)
- Migraine with visual aura
- Angle-closure glaucoma
Correct answer: Amaurosis fugax (transient monocular blindness)
Amaurosis fugax is transient monocular blindness caused by embolic occlusion of the ophthalmic artery and is a TIA equivalent requiring urgent workup.
Question 4: Which of the following anti-epileptic drugs is contraindicated in juvenile myoclonic epilepsy due to risk of worsening seizures?
- Valproate
- Carbamazepine (Correct answer)
- Levetiracetam
- Lamotrigine
Correct answer: Carbamazepine
Carbamazepine and phenytoin can paradoxically worsen myoclonic and absence seizures in JME by blocking sodium channels that exacerbate this generalized epilepsy.
Question 5: A patient with cervical myelopathy presents with bilateral upper extremity weakness, hand clumsiness, and hyperreflexia in the legs. What is the most appropriate initial imaging?
- Plain cervical X-ray
- MRI cervical spine without contrast (Correct answer)
- CT myelography
- EMG/nerve conduction study
Correct answer: MRI cervical spine without contrast
MRI of the cervical spine is the first-line imaging for suspected myelopathy, best demonstrating cord compression and signal changes.
Question 6: A 50-year-old with a history of hypertension develops sudden onset of rotatory vertigo, nausea, and inability to walk. There is nystagmus and ipsilateral limb ataxia. Which structure is most likely affected?
- Vestibular nerve
- Cerebellum (posterior inferior) (Correct answer)
- Cochlea
- Brainstem (pons)
Correct answer: Cerebellum (posterior inferior)
Sudden vertigo with ipsilateral limb ataxia and inability to walk points to cerebellar infarction in the PICA territory, which is a stroke emergency.
Question 7: A 60-year-old with known lung cancer presents with confusion, proximal weakness, and serum sodium of 118 mEq/L. Urine sodium is elevated and urine osmolality is high. What is the mechanism?
- Cerebral salt wasting
- Syndrome of inappropriate ADH secretion (SIADH) (Correct answer)
- Adrenal insufficiency
- Nephrogenic diabetes insipidus
Correct answer: Syndrome of inappropriate ADH secretion (SIADH)
SIADH from ectopic ADH production by small cell lung cancer causes dilutional hyponatremia with inappropriately elevated urine osmolality and sodium.
MD Central Nervous System Disorders 5
A 22-year-old college student presents with fever, severe headache, photophobia, and neck stiffness.
CSF shows WBC 2,000 (90% PMNs), low glucose, high protein.
What is empiric treatment?