Delirium.

Delirium is a true medical emergency that can masquerade as chronic dementia or functional psychosis and obscure the causative underlying physical or toxic disorder. In most cases, a well-focused history and thorough physical examination can unmask the delirium and reveal the medical or toxic problem. Carefully selected diagnostic testing can be required.

Emergency management of the medical or toxic disorder is the same as in nondelirious patients. Control of agitated or aggressive behavior with pharmacologic or physical restraints and special support measures are required to facilitate ED care. Delirious patients whose symptoms do not totally resolve in the ED must be admitted.