PANCE Neurologic System 3 — Questions and Answers
Question 1: A 72-year-old woman presents with a 6-month history of progressive memory loss, gait disturbance, and urinary incontinence. CT shows enlarged ventricles out of proportion to cortical atrophy. What is the diagnosis?
- Alzheimer disease
- Normal pressure hydrocephalus (Correct answer)
- Lewy body dementia
- Vascular dementia
Correct answer: Normal pressure hydrocephalus
Normal pressure hydrocephalus presents with the triad of gait apraxia, cognitive decline, and urinary incontinence with ventriculomegaly disproportionate to atrophy.
Question 2: A patient is found to have a Horner syndrome (ptosis, miosis, anhidrosis) on the right side. Which of the following is the most concerning etiology?
- Cluster headache
- Carotid artery dissection (Correct answer)
- Migraine with aura
- Benign Raeder syndrome
Correct answer: Carotid artery dissection
Carotid artery dissection can interrupt the sympathetic fibers traveling along the carotid sheath and is a life-threatening cause of Horner syndrome requiring urgent imaging.
Question 3: A 28-year-old woman presents with optic neuritis and a prior episode of transverse myelitis. MRI shows periventricular white matter lesions disseminated in time and space. Which treatment reduces long-term disability?
- Prednisone taper alone
- Disease-modifying therapy (e.g., interferon beta or natalizumab) (Correct answer)
- IV methylprednisolone indefinitely
- Plasmapheresis every 6 months
Correct answer: Disease-modifying therapy (e.g., interferon beta or natalizumab)
Disease-modifying therapies reduce relapse rate and MRI lesion burden in relapsing-remitting MS; IV steroids treat acute attacks but do not alter long-term disease course.
Question 4: A 45-year-old construction worker develops slowly progressive bilateral hand weakness with wasting of thenar and hypothenar muscles, fasciculations, and hyperreflexia. The most likely diagnosis is:
- Cervical myelopathy
- Amyotrophic lateral sclerosis (Correct answer)
- Syringomyelia
- Multifocal motor neuropathy
Correct answer: Amyotrophic lateral sclerosis
ALS presents with combined upper (hyperreflexia, spasticity) and lower (fasciculations, weakness, atrophy) motor neuron signs without sensory involvement.
Question 5: A patient taking phenytoin for seizures presents with nystagmus, ataxia, and diplopia. Serum phenytoin level is 28 mcg/mL (therapeutic 10–20). What is the best management?
- Add valproate for better seizure control
- Reduce phenytoin dose (Correct answer)
- Switch to levetiracetam immediately
- Increase phenytoin to achieve higher levels
Correct answer: Reduce phenytoin dose
Phenytoin toxicity causes nystagmus, ataxia, and diplopia at supratherapeutic levels; dose reduction is the appropriate management.
Question 6: A 60-year-old man has sudden severe 'thunderclap' headache reaching peak intensity in seconds. CT head is negative. What is the next best step?
- Discharge with NSAIDs for presumed tension headache
- Lumbar puncture to evaluate for xanthochromia (Correct answer)
- MRI brain with gadolinium
- EEG to rule out seizure
Correct answer: Lumbar puncture to evaluate for xanthochromia
A negative CT does not rule out subarachnoid hemorrhage; LP is required to detect xanthochromia or blood in the CSF when CT is negative.
Question 7: Which cranial nerve is responsible for the corneal reflex afferent limb?
- CN III
- CN V (ophthalmic branch) (Correct answer)
- CN VII
- CN VI
Correct answer: CN V (ophthalmic branch)
The afferent limb of the corneal reflex is mediated by CN V1 (ophthalmic branch of trigeminal nerve); the efferent limb is CN VII (facial nerve).
PANCE Neurologic System 3
A 72-year-old woman presents with a 6-month history of progressive memory loss, gait disturbance, and urinary incontinence.
CT shows enlarged ventricles out of proportion to cortical atrophy.
What is the diagnosis?