Catatonia vis-à-vis delirium: the significance of recognizing catatonia in altered mental status.

BACKGROUND: Catatonia is seldom considered in evaluation of altered mental status (AMS) in medical settings. Furthermore, catatonia often meets delirium criteria due to incoherence, altered awareness and behavioral change. Catatonia may co-occur with or be preferentially diagnosed as delirium.
METHODS: We conducted a systematic literature review of MEDLINE, EMBASE and PsycINFO on the relationship between catatonia and delirium. We also juxtapose clinical features of these syndromes and outline a structured approach to catatonia evaluation and management in acute medical settings.
RESULTS: These syndromes share tremendous overlap: the historical catatonia-related terms "delirious mania" and "delirious depression" bespeak of literal confusion differentiating them. Only recently has evidence on their relationship progressed beyond case series and reports. Neurological conditions account for the majority of medical catatonia cases.
CONCLUSIONS: New-onset catatonia warrants a medical workup, and catatonic features in AMS may guide clinicians to a neurological condition (e.g., encephalitis, seizures or structural central nervous system disease). Lorazepam or electroconvulsive therapy (ECT) should be considered even in medical catatonia, and neuroleptics should be used with caution. Moreover, ECT may prove lifesaving in malignant catatonia. Further studies on the relationship between delirium and catatonia are warranted.