Delirium classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sara Zand, M.D.[2] Pratik Bahekar, MBBS [3]; Vishal Khurana, M.B.B.S., M.D. [4]

Overview

Delirium is classified on the basis of etiology, duration, and severity. Hyperactive delirium is defined as increased psychomotor activity, which may occur with increased mood lability, agitation, non cooperative attitude towards medical treatment. Hypoactive delirium is explained by a hypoactive level of psychomotor activity, which may exist along with increased lethargy or stupor, inattentiveness and motor slowness and is much more common among ICU admitted patients with severe disease.

Delirium may be classified into the following:

Diagnostic and Statistical Manual (DSM)-5	World Health Organization’s International Classification of Diseases (10th revision)	ICD-10
Disturbance in attention and awareness (reduced ability to direct, focus, shift attention and reduced orientation to envinment) Initiation of disturbance over a short period of time during several hours or days with fluctuation in severity over a day Disturbance in cognition (memory deficit, disorientation, language, visuospatial ability, perception Disturbance other than evolving neurocognitive disorder Disturbance due to medical condition, substance intoxication, or withdrawal, toxin exposure	Disturbance in cognition Impairment of immediate recall and recent memory Disorientation to time, place, person	Disturbance in sleep wake cycle Psychomotor disturbances Emotional disturbances Upper limit time: 6 months

Classification based on	Types
Etiology	Substance intoxication delirium
	Substance withdrawal delirium
	Delirium caused by another medical condition
	Delirium caused by multiple etiologies
Duration	Acute
Duration	Persistent
Severity	Hyperactive
	Hypoactive
	Mixed level of activity

Hyperactive: An increased psychomotor activity, which may co-occur with, increased mood lability, agitation, and/or non cooperative attitude towards medical treatment.
Hypoactive: A hypoactive level of psychomotor activity, which may exist along with increased sluggishness, lethargy or stupor, inattentiveness and motor slowness and is much more common among ICU admitted patients with severe disease.^[1]
Mixed level of activity: A normal level of psychomotor activity, individuals with rapidly fluctuating activity are also included in this category.^[2]

Some authors have described a fourth type of delirium called as subsyndromal delirium, which is an incomplete form of delirium.^[3]

↑ Krewulak, Karla D.; Stelfox, Henry T.; Leigh, Jeanna Parsons; Ely, E. Wesley; Fiest, Kirsten M. (2018). “Incidence and Prevalence of Delirium Subtypes in an Adult ICU”. Critical Care Medicine. 46 (12): 2029–2035. doi:10.1097/CCM.0000000000003402. ISSN 0090-3493.
↑ Inouye, SK.; Westendorp, RG.; Saczynski, JS. (2013). “Delirium in elderly people”. Lancet. doi:10.1016/S0140-6736(13)60688-1. PMID 23992774. Unknown parameter |month= ignored (help)
↑ Young, J.; Inouye, SK. (2007). “Delirium in older people”. BMJ. 334 (7598): 842–6. doi:10.1136/bmj.39169.706574.AD. PMID 17446616. Unknown parameter |month= ignored (help)