Cholinergic crisis

(Redirected from Cholinergic)


  • Neuromuscular junction over-stimulation due to an excess of acetylcholine (ACh), as of a result of the inhibition of the AChE enzyme (which normally breaks down acetylcholine)


  • The neuromuscular junction, where the brain communicates with muscles (e.g. the diaphragm), works by acetylcholine activating nicotinic acetylcholine receptors and leading to muscle contraction.
  • Atropine blocks muscarinic acetylcholine receptors (a different subtype than the nicotinic receptors at the neuromuscular junction), so will not improve the muscle strength and ability to breathe.
    • So, such patients will frequently require mechanical ventilation until the crisis resolves. There is not specific antidote for the respiratory compromise.

Autonomic Nervous System Receptors and Their Effects

  • Parasympathetic - ACh is transm
    • Muscarinic
      • receptors in heart, eye, lung, GI, skin and sweat glands
      • Bradycardia
      • Miosis
      • Bronchorrhea / Bronchospasm
      • Hyperperistalsis (SLUDGE)
      • Sweating
      • Vasodilation
    • Nicotinic
  • Sympathetic
    • Alpha effects (vessels, eye, skin)
    • Beta effects (heart, lungs)

Clinical Features

SLUDGE(M) syndrome

Salivation, Lacrimation, Urination, Diarrhea, GI pain, Emesis, Miosis

Differential Diagnosis

SLUDGE Syndrome


Myasthenic versus cholinergic crisis

Flaccid paralysis resulting from cholinergic crisis can be distinguished from myasthenia gravis by the use of the drug edrophonium, which worsens the paralysis caused by cholinergic crisis, but strengthens the muscle in the case of myasthenia gravis. (Edrophonium is an cholinesterase inhibitor hence increases the concentration of acetylcholine present).

  • Myasthenic Crisis
    • Respiratory failure is feared complication
    • Much more common
    • Due to medication non-adherence, infection, surgery, tapering of immunosuppressants, meds
  • Cholinergic Crisis
    • Excessive anticholinesterase medication may cause weakness and cholinergic symptoms
    • Rarely if ever seen with dose limitation of pyridostigmine to less than 120mg q3hr
    • If on usual dose of meds assume exacerbation due to MG even with cholinergic side effects
  • Edrophonium (Tensilon) test to distinguish the two is controversial
    • Give 1-2mg IV slow push. If any fasciculations, respiratory depression, or cholinergic symptoms within a few minutes, problem is likely cholinergic crisis (no more edrophonium). If no evidence of cholinergic excess, give total of 10mg and observe improvement in case of myasthenic crisis.
    • Side effects of Edrophonium: Arrhythmias, Hypotension, Bronchospasm
    • Thus, need to be on a monitor, with atropine on hand
    • Treatment: Atropine


  • Decontaminate immediately - takes priority, prevent exposure of health care workers, remove patient from exposure and remove all clothing
  • Atropine (antimuscarinic)
    • 2-4mg IV q5min, titrate to resolution of bronchorrhea (may need > 100 mg total dose)
    • Then initiate atropine infusion at 10% of total initial dose and titrate up by 0.2 mg/kg/hr to maintain resolution of bronchorrhea
  • Benzodiazepines prn for seizures
    • Lorazepam 2-4 mg IV
  • Pralidoxime (2-PAM)
    • Loading dose 20 mg/kg (max 2 g) IV bolus x 30 minutes then
    • Infusion 8-10 mg/kg/hr (max 650 mg/hr) IV
  • Consider intubation and mechanical ventilation
    • Poisoning of acetylcholinesterase will prolong effects of succinylcholine. Consider nondepolarizing agent such as rocuronium if paralytic needed


  • Admit, consider ICU

See Also

External Links