Neuromuscular Disorders USMLE Step 1 Practice Question
A 52-year-old man presents to the emergency department with jaw stiffness and severe generalized muscle spasms 1 week after a puncture wound from a rusty nail. Vital signs show BP 152/94, HR 110, RR 22, temperature 37.8°C, SpO2 98% on room air. Examination reveals risus sardonicus, opisthotonos, and rigid back muscles. Serum electrolytes are normal; EMG shows characteristic "motor unit action potentials." He denies recent antibiotic use. Which neurotransmitter is most directly affected by this toxin?
Answer choices
- AAcetylcholine and serotonin
- BGlycine and GABACorrect answer
- CDopamine and norepinephrine
- DHistamine and acetylcholine
- EGlutamate and aspartate
- FF. GABA and glutamate
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