PANRE Neurology 2 — Questions and Answers
Question 1: A 68-year-old man presents with sudden onset of the worst headache of his life. CT head is negative. What is the next best step?
- Lumbar puncture (Correct answer)
- MRI brain with contrast
- Start empiric antibiotics
- Discharge with analgesics
Correct answer: Lumbar puncture
A negative CT does not rule out subarachnoid hemorrhage; lumbar puncture is required to detect xanthochromia or RBCs that persist after centrifugation.
Question 2: Which medication is first-line for absence seizures in a 10-year-old child?
- Levetiracetam
- Ethosuximide (Correct answer)
- Carbamazepine
- Phenytoin
Correct answer: Ethosuximide
Ethosuximide is first-line for childhood absence epilepsy because it targets thalamic T-type calcium channels responsible for spike-and-wave discharges.
Question 3: A patient with multiple sclerosis develops painful, unilateral vision loss with a central scotoma. Which structure is most likely inflamed?
- Optic chiasm
- Optic nerve (Correct answer)
- Lateral geniculate nucleus
- Occipital cortex
Correct answer: Optic nerve
Optic neuritis — inflammation of the optic nerve — is a common initial presentation of MS and causes monocular vision loss with pain on eye movement.
Question 4: A 55-year-old presents with resting tremor, bradykinesia, and cogwheel rigidity. Which neurotransmitter pathway is most affected?
- Nigrostriatal dopaminergic (Correct answer)
- Corticospinal glutamatergic
- Limbic serotonergic
- Cerebellar GABAergic
Correct answer: Nigrostriatal dopaminergic
Parkinson disease results from degeneration of dopaminergic neurons in the substantia nigra pars compacta, disrupting the nigrostriatal pathway.
Question 5: A 72-year-old woman on warfarin falls and loses consciousness. CT shows a lens-shaped hyperdense collection. Which vessel is most likely injured?
- Middle meningeal artery (Correct answer)
- Bridging veins
- Anterior cerebral artery
- Basilar artery
Correct answer: Middle meningeal artery
An epidural hematoma has a biconvex (lens-shaped) appearance and typically results from rupture of the middle meningeal artery after temporal bone fracture.
Question 6: Which finding on nerve conduction studies best distinguishes demyelinating neuropathy from axonal neuropathy?
- Reduced amplitude of CMAP
- Slowed conduction velocity with conduction block (Correct answer)
- Absent F-waves only
- Increased insertional activity on EMG
Correct answer: Slowed conduction velocity with conduction block
Demyelinating neuropathies are characterized by markedly slowed conduction velocities and conduction block, reflecting impaired myelin function rather than axon loss.
Question 7: A patient presents with ataxia, nystagmus, and ophthalmoplegia. What is the immediate priority treatment?
- Glucose infusion
- Thiamine (vitamin B1) administration (Correct answer)
- Naloxone IV
- Lorazepam IV
Correct answer: Thiamine (vitamin B1) administration
This classic triad represents Wernicke encephalopathy; thiamine must be given before glucose to prevent worsening or precipitation of the syndrome.
PANRE Neurology 2
A 68-year-old man presents with sudden onset of the worst headache of his life.
CT head is negative.
What is the next best step?