NBME Clinical Neurology 4

Question 1

A 55-year-old man with small cell lung cancer has proximal limb weakness that improves with repeated muscle use. Reflexes are reduced. Anti-VGCC antibodies are positive. What is the diagnosis?

Accepted Answer

Lambert-Eaton myasthenic syndrome

Answer

Lambert-Eaton myasthenic syndrome (LEMS) is caused by anti-VGCC antibodies, often paraneoplastic with SCLC, and shows strength facilitation with repetitive activity.

Question 2

A 5-year-old boy has calf pseudohypertrophy, Gowers' sign, and CK >10,000 U/L. Genetic testing shows a frameshift deletion in dystrophin exon 50. What is the mode of inheritance?

Accepted Answer

X-linked recessive

Answer

Duchenne muscular dystrophy is caused by frameshift mutations in the dystrophin gene on chromosome Xp21, inherited in an X-linked recessive pattern.

Question 3

A patient suffers a spinal cord injury and has loss of pain and temperature bilaterally below the lesion, with preserved proprioception and vibration. Upper motor neuron signs are present. Which syndrome is this?

Accepted Answer

Anterior cord syndrome

Answer

Anterior cord syndrome disrupts the spinothalamic tracts (pain/temperature) bilaterally while sparing the posterior columns (proprioception/vibration); typically from anterior spinal artery infarction.

Question 4

A 3-year-old child presents with fever, neck stiffness, and petechial rash. CSF shows glucose 30 mg/dL (serum 90), protein 180 mg/dL, WBC 1,200 (90% PMN). What organism is most likely?

Accepted Answer

Neisseria meningitidis

Answer

N. meningitidis classically causes bacterial meningitis with petechial/purpuric rash in children and young adults and is the most common cause of epidemic meningitis.

Question 5

A 35-year-old man presents 3 weeks after GI illness with ascending weakness, areflexia, and albuminocytologic dissociation on CSF (elevated protein, normal cell count). What is the most important acute complication to monitor?

Accepted Answer

Autonomic cardiac arrhythmia and respiratory failure

Answer

Guillain-Barré syndrome can cause life-threatening respiratory failure and autonomic instability (arrhythmias, BP fluctuations) requiring close ICU monitoring.

NBME Practice Test

NBME Practice Test

NBME Clinical Neurology 4