Reference — Neurology
Myasthenic vs Cholinergic Crisis Reference
Both crises in myasthenia gravis look the same at first glance — a patient too weak to breathe — but they come from opposite causes (too little drug vs too much). The muscarinic SLUDGE signs and the pupils sort them out. Either way, the airway comes first.
Educational use only. Crisis management is an emergency and specialist-directed. The Tensilon (edrophonium) test, when used, is performed under controlled conditions with atropine available — do not give or withhold anticholinesterases without orders. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Side by Side
| Feature | Myasthenic crisis | Cholinergic crisis |
|---|---|---|
| Cause | TOO LITTLE medication, or a stressor (infection, surgery, missed dose) overwhelming it | TOO MUCH anticholinesterase medication (overmedication) |
| Core problem | Severe weakness from inadequate acetylcholine effect | Severe weakness from acetylcholine EXCESS at the junction |
| Extra (muscarinic) signs | Mainly weakness; signs of the precipitating infection may be present | SLUDGE — Salivation, Lacrimation, Urination, Diarrhea, GI cramping, Emesis; plus sweating, bronchial secretions |
| Pupils | Normal or unaffected | Miosis (small pupils) |
| Muscle extras | Weakness/fatigability | Fasciculations, muscle cramps |
| Both share | Profound weakness, dysphagia, respiratory failure — airway is the priority | Profound weakness, dysphagia, respiratory failure — airway is the priority |
Sorting Them Out
SLUDGE + miosis + fasciculations = cholinergic (too much drug) — the muscarinic overflow is the giveaway. Their absence, especially with a missed dose or a new infection, points to myasthenic crisis (too little).
The edrophonium (Tensilon) test historically distinguished them: brief improvement suggests myasthenic crisis (needs more drug); worsening suggests cholinergic (needs less). It is done cautiously with atropine at the bedside as the antidote for cholinergic effects.
Regardless of type, protect the airway first — monitor FVC/NIF, keep suction and intubation ready, and support ventilation. Sorting the cause guides whether anticholinesterase is given or held, but it never precedes airway management.
NCLEX Pearls
- ✦Myasthenic crisis = too LITTLE medication (or a stressor); cholinergic crisis = too MUCH anticholinesterase.
- ✦Cholinergic excess shows SLUDGE (salivation, lacrimation, urination, diarrhea, GI cramps, emesis) + miosis + fasciculations.
- ✦Atropine is the antidote for cholinergic crisis; keep it ready with the edrophonium (Tensilon) test.
- ✦Both cause respiratory failure — airway protection (FVC/NIF, suction, intubation readiness) comes before sorting the cause.
- ✦A missed dose or new infection points toward myasthenic crisis.
Related Resources
Standards & sources
Fact-checked Jun 21, 2026This page is written to align with American Heart Association / American Stroke Association (AHA/ASA) · American Association of Neuroscience Nurses (AANN). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →