UMEM Educational Pearls


A patient presents with altered mental status for unclear reasons- could it be anticholinergic syndrome? 


There are many medications (e.g. Beers Criteria, see pearl from March 5, 2017) and plants (e.g.: certain mushrooms) that can cause this life-threatening toxidrome.


The quick mnemonic for anticholinergic poisoning is:

·      Hot as a hare (hyperthermia)

·      Red as a beet (flushed)

·      Cry as a bone (decreased secretions)

·      Blind as a bat (mydriasis)

·      Mad as a hatter (delirium)

·      Full as a flask (urinary retention)


Bottom line: Keep anticholinergic syndrome within your differential for a patient with altered mental status without a clear cause.  


Note: An earlier version of this pearl incorrectly listed organophospahtes, which cause cholingeric toxicity.


The clinical manifestations of anticholinergic syndrome can be extensive. Additional symptoms can include:


·       “Sinus tachycardia

·       Decreased bowel sounds

·       Functional ileus

·       Urinary retention

·       Hypertension

·       Tremulousness

·       Myoclonic jerking


Patients with central anticholinergic syndrome may present with the following:

·       Ataxia

·       Disorientation

·       Short-term memory loss

·       Confusion

·       Hallucinations (visual, auditory)

·       Psychosis

·       Agitated delirium

·       Seizures (rare)

·       Coma

·       Respiratory failure

·       Cardiovascular collapse”1