Bacterial Infections USMLE Step 1 Practice Question
A 52 year old man comes to the emergency department with jaw stiffness and painful muscle spasms 8 days after stepping on a rusty nail while working on a farm. He has not received routine medical care for many years. Examination shows risus sardonicus and generalized hyperreflexia. Which of the following is the most likely mechanism of the toxin responsible for this patient’s symptoms?
Answer choices
- ABlockade of glycine and GABA release from inhibitory interneuronsCorrect answer
- BActivation of adenylate cyclase in enterocytes
- CInhibition of acetylcholine release at the neuromuscular junction
- DDirect endothelial invasion causing vasculitis
- EInactivation of the 60S ribosomal subunit
- FActivation of voltage-gated calcium channels in skeletal muscle
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