Toxicology USMLE Step 1 Practice Question
A 47-year-old woman with myasthenia gravis self-increased her pyridostigmine dose. She now presents with BP 138/82, HR 108, RR 18, temp 37.2°C, SpO2 98% on room air. She reports severe diarrhea, profuse sweating, and miosis. Examination reveals visible muscle fasciculations and proximal weakness. Serum potassium is 3.1 mEq/L. She denies recent trauma or infection. Which of the following best explains her current deterioration?
Answer choices
- AMyasthenic crisis due to too little acetylcholine at nicotinic receptors
- BCholinergic crisis from excess acetylcholinesterase inhibitionCorrect answer
- CLambert-Eaton syndrome
- DAcute intermittent porphyria
- EBotulinum toxin poisoning
- FAnticholinergic toxidrome from accidental ingestion of atropine-containing medication
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