A 50-year-old woman with myasthenia gravis, recently self-escalated her pyridostigmine dose, reports worsening cramps and diarrhea. On examination she has miosis, fasciculations, sweating, and increased weakness. What is the next step?

• A Increase pyridostigmine dose further
• B Start oral prednisolone
• C Give neostigmine intramuscularly as a test dose
• D Withhold cholinesterase inhibitor and observe for improvement ✓

Explanation

Excessive cholinesterase inhibition produces a cholinergic crisis with muscarinic features such as miosis, diarrhea, sweating, and bronchorrhea, plus nicotinic effects including fasciculations and paradoxical weakness. The correct action is stopping the anticholinesterase and supportive care while distinguishing it from myasthenic crisis. Giving more pyridostigmine or neostigmine would worsen it, and steroids act too slowly to address an acute cholinergic excess.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.