A 40-year-old woman with myasthenia gravis (AChR antibody positive) is admitted with severe dysphagia, respiratory weakness requiring ventilation, and generalized limb weakness. She was started on pyridostigmine 3 weeks ago and the dose was recently increased. She now has excessive salivation, miosis, abdominal cramps, and fasciculations. Tensilon (edrophonium) test does not improve weakness. Which is the most appropriate immediate management?

• A Increase pyridostigmine dose
• B Initiate plasma exchange and continue current pyridostigmine
• C Administer intravenous methylprednisolone 1 g/day
• D Stop pyridostigmine temporarily, give atropine for secretions, and provide ventilatory support ✓

Explanation

This is a cholinergic crisis: excessive cholinergic stimulation from pyridostigmine causing muscarinic symptoms (miosis, salivation, cramps, bradycardia) and nicotinic effects (fasciculations, worsening weakness). The Tensilon test not improving weakness supports cholinergic rather than myasthenic crisis. Management is to stop cholinesterase inhibitors, give atropine for muscarinic symptoms, and provide ventilatory support. Increasing pyridostigmine would worsen the crisis. Plasma exchange is for severe myasthenic crisis, not cholinergic crisis.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.