Substance‑induced delirium (intoxication and withdrawal)

Delirium from intoxication or withdrawal: substances, mechanisms, and urgent risks.

Key points

• Intoxication and withdrawal are time‑critical causes of delirium; some presentations are life‑threatening.
• History is pivotal: new or higher doses, drug combinations (including alcohol), and abrupt cessation of alcohol/benzodiazepines.
• Suspected poisoning, depressed breathing, seizure, severe agitation or hyperthermia → emergency care.

Clinical context

Delirium may arise from direct toxicity (overdose, interaction, accumulation in renal/hepatic impairment) or from withdrawal (especially alcohol and benzodiazepines). Presentations range from profound somnolence with respiratory depression to marked agitation with hallucinations and autonomic instability.

Intoxication patterns

• Sedatives/hypnotics and opioids: drowsiness, slowed breathing, falls.
• Anticholinergic drugs: dry mouth, mydriasis, tachycardia, urinary retention, confusion.
• Serotonergic toxicity: agitation, hyperreflexia, fever (consider serotonin syndrome).
• Stimulants: paranoia, tachycardia, hypertension, hyperthermia.

Withdrawal states

Alcohol and benzodiazepine withdrawal can progress to severe agitation, tremor, hallucinations, seizures and autonomic instability. Delirium tremens is the most severe form and requires hospital management.

Assessment

Start with ABC, oxygenation and bedside glucose. Obtain a precise substance/medication timeline: what was taken, dose, timing, and co‑ingestions. Look for withdrawal risk (last drink/last benzodiazepine dose). In healthcare settings, typical work‑up includes electrolytes, renal/hepatic function, ECG (QT), and targeted toxicology tests when clinically useful.

Management & safety

Treatment is supportive and cause‑specific (e.g., withdrawal protocols). Avoid unsupervised “calming” medications at home; focus on safety and rapid access to medical care when red flags are present.

Practical tables

Related topics

Delirium tremens • Medication‑induced delirium • When it is urgent