What symptom is indicated by the term "mad as a hatter" in anticholinergic toxidrome?

The term "mad as a hatter" refers to altered mental status, a classic symptom associated with anticholinergic toxidrome. In historical context, this phrase originated from the effects of mercury poisoning observed in hat makers, who used mercury in the production of felt hats. The toxicity led to neurological symptoms, including confusion, delirium, and hallucinations, which are similar to what is seen in modern cases of anticholinergic poisoning.

In the context of anticholinergic toxidrome, substances that block the action of acetylcholine can lead to a variety of central nervous system effects. The disturbed mental state can manifest as agitation, confusion, or even coma, depending on the severity of the poisoning. This altered mental status is a key diagnostic feature that helps differentiate anticholinergic toxicity from other conditions with similar presentations and is crucial for determining the appropriate management and treatment strategies for affected patients.