---
title: "Delirium"
url: https://mghmclean.org/residents/handbk/part2b/del.htm
description: "source : Trepacz P et al. (1999) Am J Psychiatry 156:5 (supplement)"
published: 2026-08-10
updated: 2026-08-10
---

# Delirium

Published 2026-08-10

PART 3 / CH 30

Roy Perlis

A. Definition (DSM-IV)

1. disturbed consciousness with impaired attention

2. impaired cognition or perception

3. acute onset (hrs-days) with fluctuating course

(best bedside tests: clock-drawing, go/no-go)

B. Common associated features

1. increased or decreased psychomotor activity

2. fearfulness/paranoia/lability

3. disturbed sleep-wake cycle

4. misperceptions, visual hallucinations

C. Life-threatening etiologies: OHHH, SHIT!

|  | etiology | evaluation |
|---|---|---|
| O | hypoxia | O2 sat |
| H | hypoperfusion | HR/bp |
| H | hypertensive encephalopathy |  |
| H | hypoglycemia | FS-glucose |
| S | stroke | imaging |
| H | hemorrhage (intracranial) | imaging |
| I | infection (meningitis, encephalitis) | temp., WBC |
| T | toxins (barbiturate w.d., Wernicke’s, CO, …) | labs |

D. Medications commonly associated with delirium

1. anticholinergics/ antihistamines

2. narcotics, especially demerol (normeperidine)

3. antiarrhythmics, antihypertensives, beta blockers

4. antibiotics (penicillin, rifampin)

5. corticosteroids

6. anticonvulsants, neuroleptics (anticholinergic), lithium

E. Differential diagnosis

| Type | Examples |
|---|---|
| Medications | see table |
| Intoxication/Withdrawal | alcohol, benzodiazepines, barbiturates, narcotics, PCP, hallucinogens |
| Intracranial | seizure or postictal statehemorrhage, hypertensive encephalopathy, strokeneoplasm (primary/metastatic)infection (meningitis/encephalitis, HIV, neurosyph.)NPH |
| Metabolic | renal failure (uremia), hepatic failurehypoglycemia, diabetic ketoacidosisfluid, acid-base or electrolyte disturbanceparathyroid/thyroid/adrenal dysfunctionthiamine deficiency (Wernicke’s) |
| Cardiovasc. | myocardial infarction, CHF, arrhythmiarespiratory failure, hypoxia, anemia |
| Systemic | infection (any, including endocarditis) paraneoplastic, postoperative |

*source*: Trepacz P et al. (1999) Am J Psychiatry 156:5 (supplement)