In a cholinergic crisis due to myasthenia gravis after edrophonium challenge, which intervention primarily addresses muscarinic symptoms?

In a cholinergic crisis due to myasthenia gravis after edrophonium challenge, which intervention primarily addresses muscarinic symptoms?

• A. Atropine
• B. Edrophonium
• C. Neostigmine
• D. Epinephrine

Answer: (A)

Cholinergic crisis from myasthenia gravis after an edrophonium challenge occurs when excess acetylcholine overstimulates both nicotinic and muscarinic receptors. The muscarinic overactivity causes bronchorrhea, bradycardia, miosis, sweating, GI cramps, and other autonomic symptoms. To specifically counter these muscarinic effects, atropine is used because it blocks muscarinic receptors, reversing the autonomic manifestations without affecting the nicotinic receptor–mediated skeletal muscle weakness. Edrophonium or neostigmine would increase acetylcholine and worsen muscarinic symptoms. Epinephrine does not selectively address the muscarinic excess.

Cholinergic crisis from myasthenia gravis after an edrophonium challenge occurs when excess acetylcholine overstimulates both nicotinic and muscarinic receptors. The muscarinic overactivity causes bronchorrhea, bradycardia, miosis, sweating, GI cramps, and other autonomic symptoms. To specifically counter these muscarinic effects, atropine is used because it blocks muscarinic receptors, reversing the autonomic manifestations without affecting the nicotinic receptor–mediated skeletal muscle weakness.

Edrophonium or neostigmine would increase acetylcholine and worsen muscarinic symptoms. Epinephrine does not selectively address the muscarinic excess.