Substance intoxication

Slurred, tangential, incoherent, overinclusive speech after drugs/alcohol

EmergentReview due

At a glance

High-risk causes: 6
Core tests: 2
Immediate actions: 6
Related differentials: 8

Safety snapshot

Watch forOpioid respiratory depressionhead injuryhyperthermiaRespiratory depressionchest painhyperthermia

Presentation hinge

Inattention plus altered awareness/arousal are the key separators. Usually precipitated by acute illness, surgery, injury, retention, constipation, pain, or medicines.

Separates the Delirium / Acute Confusion / Encephalopathy group. It is not specific to Substance intoxication.

Points for this presentation

Applies to the Delirium / Acute Confusion / Encephalopathy group — not specific to Substance intoxication

Do vitals, BGL, sats, attention testing, collateral, and medication/substance review early
Use 4AT in most adult settings, and ICU tools where appropriate
Quiet hypoactive delirium is commonly missed
Treat precipitants and use non-drug care first

Clinical review

Rows marked “Whole group”: Applies to the Delirium / Acute Confusion / Encephalopathy group — not specific to Substance intoxication

Why it fits

Slurred, tangential, incoherent, overinclusive speech after drugs/alcohol

Key features2 features

Time-link to use, toxidrome clues (pupils, RR, nystagmus, tremor)
Formal thought disorder plus broader psychotic syndrome and functional deterioration.

Must-not-miss

Opioid respiratory depression, head injury, hyperthermia.

High-risk causes6 causes

Opioid respiratory depression
head injury
hyperthermia
Respiratory depression
chest pain
trauma

Bedside question

Applies to the Delirium / Acute Confusion / Encephalopathy group.

Inattention plus altered awareness/arousal are the key separators. Usually precipitated by acute illness, surgery, injury, retention, constipation, pain, or medicines.

Helpful clues1 clue

Formal thought disorder plus broader psychotic syndrome and functional deterioration.

Immediate action

Applies to the Delirium / Acute Confusion / Encephalopathy group.

Do vitals, BGL, sats, attention testing, collateral, and medication/substance review early Use 4AT in most adult settings, and ICU tools where appropriate Quiet hypoactive delirium is commonly missed Treat precipitants and use non-drug care first Reserve antipsychotics for severe distress or immediate risk Do not stop at behavioural labels

Priority steps6 steps

1Do vitals, BGL, sats, attention testing, collateral, and medication/substance review early
2Use 4AT in most adult settings, and ICU tools where appropriate
3Quiet hypoactive delirium is commonly missed
4Treat precipitants and use non-drug care first
5Reserve antipsychotics for severe distress or immediate risk
6Do not stop at behavioural labels

Investigations

Applies to the Delirium / Acute Confusion / Encephalopathy group.

Blood glucose, Vitals and oxygen saturation

Core tests2

Blood glucose
Vitals and oxygen saturation

Mimics / overlap

Applies to the Delirium / Acute Confusion / Encephalopathy group.

Primary psychosis, dementia, severe depression, catatonia, intoxication, post-ictal state, stroke, medication overdose, stimulant intoxication

Consider8

Points for this presentation

Applies to the Delirium / Acute Confusion / Encephalopathy group — not specific to Substance intoxication

Do vitals, BGL, sats, attention testing, collateral, and medication/substance review early
Use 4AT in most adult settings, and ICU tools where appropriate
Quiet hypoactive delirium is commonly missed
Treat precipitants and use non-drug care first

First-line tests

Applies to the Delirium / Acute Confusion / Encephalopathy group — not specific to Substance intoxication

Blood glucose
Vitals and oxygen saturation

Watch for

Opioid respiratory depression
head injury
hyperthermia
Respiratory depression
chest pain
hyperthermia

Also consider

Source and review

Review due· Unverified

v10 · exported 2026-07-11

Clinical reference — not validated decision support. Review before use.