Altered Mental Status
ABCs
- airway: assess obstruction; protect if GCS ≤ 8
- breathing: SpO₂, RR; O₂ if needed; hypoxia → CO₂ retention, aspiration, pneumonia
- circulation: HR, BP, perfusion; IV access; tachycardia + hypotension → ? shock
- disability: GCS vs baseline, pupils, focal deficits; bradycardia + HTN + irregular breathing → ↑ ICP
- exposure: trauma, infection, track marks; fever → ? sepsis / meningitis / encephalitis
- temperature: fever → infection/sepsis; hypothermia → exposure, myxedema, sepsis
- check glucose early; if low → IV glucose 150–200 mL of 10% or 75–100 mL of 20% over 10–15 min; D50W 50 mL fallback if 10/20% unavailable
- review drug chart: sedatives, opioids, anticholinergics, insulin, new or recently changed medications
- define the pattern
- delirium = acute fluctuating attention/cognition change
- coma/depressed consciousness = reduced arousal
- focal deficit = stroke, bleed, mass, seizure/post-ictal
- agitation alone ≠ psychiatric until medical causes excluded
- airway unprotected (GCS ≤ 8) or hemodynamic instability → Advanced: Shock, Advanced: Mechanical Ventilation
call ICU / senior early
- deteriorating GCS
- airway compromise
- hemodynamic instability
- meningism (neck stiffness, photophobia, fever) → don’t delay antibiotics for imaging
- bradycardia + HTN + irregular breathing → ↑ ICP
HPI & examination
- onset: sudden → stroke, seizure, trauma; gradual → metabolic, toxic
- background
- dementia, epilepsy, psychiatric disease
- medications: sedatives, opioids, insulin
- substances: alcohol, drugs
- infection: UTI, pneumonia, meningitis
- other contributors
- liver disease → hepatic encephalopathy
- renal failure → uremic encephalopathy
- COPD → CO₂ retention
- urinary retention / constipation
- collateral history essential
- new confusion is medical until proven otherwise; exclude organic causes before any psychiatric label
examination clues
| finding | suggests |
|---|---|
| focal deficit | stroke, mass |
| hyperreflexia / clonus | serotonin syndrome |
| jaundice | liver disease |
| track marks | IV drug use |
| fruity odor | DKA |
| alcohol smell | intoxication |
| neck stiffness | meningitis, SAH |
| miosis (pinpoint pupils) | opioids, pontine lesion |
| mydriasis (dilated) | sympathomimetics, anticholinergics |
| asterixis (flapping tremor) | hepatic, uremic, metabolic encephalopathy |
workup
| category | test | why |
|---|---|---|
| initial (always) | glucose | rule out hypoglycemia |
| ECG | cardiac cause / arrhythmia | |
| pulse oximetry | detect hypoxia | |
| CBC, U&E, LFTs | infection, metabolic, organ dysfunction | |
| ABG / VBG | CO₂ retention, acidosis | |
| blood cultures | suspected sepsis | |
| CRP | infection screening | |
| targeted | ammonia | supports hepatic encephalopathy evaluation; not standalone diagnostic |
| TFTs | myxedema coma / thyroid storm | |
| drug levels (paracetamol, salicylates, ethanol) | toxic cause | |
| urine toxicology | substance use | |
| cortisol | if adrenal crisis suspected (unexplained hypotension, hypoglycemia) | |
| imaging | CT brain (non-contrast) | stroke, bleed, trauma, mass |
| MRI brain | if CT inconclusive (encephalitis, posterior fossa) | |
| LP (after CT excludes mass effect / raised ICP) | suspected meningitis / encephalitis |
management
- keep NPO (aspiration risk)
- reassess frequently; do not leave unstable patient
treat reversible causes
- hypoglycemia → IV glucose as in ABCs above
- Wernicke’s → thiamine 200–300 mg IV before glucose
- opioid overdose → naloxone: 0.1 mg IV and titrate (opioid-dependent); 0.4 mg IV/IM if peri-arrest or unknown (two-pathway detail)
- sepsis → fluid resuscitation + broad-spectrum antibiotics within 1 h; see empiric antibiotics; if hemodynamically unstable → shock management
- hypertensive encephalopathy → controlled BP reduction; see hypertension
- hepatic encephalopathy → lactulose 20–30 mL PO/NG q1–2h until 2–3 soft stools/day
- hypercapnia → SpO₂ 88 to 92% + BiPAP
- urinary retention → Foley catheter
- constipation → enema + stool chart
- medications → hold/stop offending drugs (sedatives, opioids, anticholinergics); check recently changed or new medications
- electrolyte imbalance → correct appropriately (see sodium)
- uremic encephalopathy → Nephrology; consider urgent dialysis
- seizure precautions if cause unclear: pad bed rails, suction at bedside; active seizure → see seizures
- stroke → see new neurological deficit
- meningitis / encephalitis → antibiotics now, do not delay
- ceftriaxone 2 g IV q12h + vancomycin 15–20 mg/kg IV q12h
- add ampicillin 2 g IV q4h if >50 y or immunocompromised
- dexamethasone 10 mg IV (≈0.15 mg/kg) with / just before the first antibiotic dose, then q6h ×4 days
- aciclovir 10 mg/kg IV q8h if HSV suspected
- full regimens: empiric antibiotics
evidence
| source | type |
|---|---|
| NICE NG103 · Delirium: prevention, diagnosis and management ↗︎ | international guideline |
| IDSA 2004 · Bacterial meningitis (empiric treatment) | specialty-society guidance |
Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.
free the on-call checklist covers the whole shift on one printable page.
studying for the IM exam? IM Rapid Review covers the confused patient in the same format. see the sample chapter.
reviewed Jun 2026updated Sep 2026file complaint/altered-mental-status