Altered Mental Status
at the bedside
- airway, breathing, circulation; protect the airway if GCS ≤ 8; full vitals, SpO₂, cardiac monitor, IV access
- disability → GCS against baseline, pupils, focal deficit
- exposure → temperature, trauma, track marks, rash; hypoxia and CO₂ retention both cloud consciousness
- capillary glucose → low → glucose 10% 150–200 mL IV over 10–15 min → hypoglycemia
- drug chart → sedatives, opioids, anticholinergics, insulin; anything new or changed
- define the pattern
- delirium → acute, fluctuating inattention → delirium
- reduced arousal → drowsy to coma
- focal deficit → stroke, bleed, mass, post-ictal → new neurological deficit
- agitation alone is medical until proven otherwise
escalate now if
- GCS ≤ 8 or falling → ICU; reversible causes in parallel → treat
- airway compromise or hemodynamic instability → hypotension
- fever with neck stiffness or photophobia → antibiotics before imaging → meningitis
- bradycardia, hypertension and irregular breathing → raised ICP → neurosurgery
differentials
by the finding
- 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
by the pattern
- delirium → acute, fluctuating inattention; infection, drugs, retention, pain, withdrawal → delirium
- reduced arousal → drugs, hypoglycemia, hypercapnia, hepatic or uremic encephalopathy, raised intracranial pressure, non-convulsive status
- focal deficit → stroke, bleed, mass, Todd paresis → neurological deficit
- fever with confusion → sepsis, meningitis, encephalitis → fever, meningitis
focused check
- 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
send now
- glucose, ECG, VBG, CBC, RFT, LFT, CRP; blood cultures if febrile
- CT head, non-contrast, after stabilisation; LP after the CT if meningitis or encephalitis is suspected; MRI if the CT is normal and encephalitis or a posterior fossa lesion is suspected
- by the picture → TSH; cortisol if unexplained hypotension or hypoglycemia; paracetamol, salicylate and ethanol levels; urine toxicology
- ammonia → only with known or suspected liver disease; it supports hepatic encephalopathy, it does not diagnose it
treat
- NPO until swallow is safe
- reassess often; an unstable patient is not left alone
treat reversible causes
- hypoglycemia → IV glucose as above → hypoglycemia
- Wernicke’s → thiamine 200–300 mg IV before glucose
- opioid toxicity → naloxone 0.1 mg IV, repeat every 2–3 min to adequate breathing; 0.4 mg IV/IM if peri-arrest → respiratory rate
- sepsis → cultures, antibiotics within 1 h → fever, empiric antibiotics; unstable → hypotension
- hypertensive encephalopathy → hypertension
- hepatic encephalopathy → lactulose 20–30 mL PO/NG q1–2h until 2–3 soft stools a day → LFT
- hypercapnia → controlled O₂ to 88–92%, NIV → respiratory rate
- urinary retention → bladder scan, catheter → urinary retention
- constipation → constipation
- drugs → hold sedatives, opioids and anticholinergics; review anything new or changed
- electrolytes → sodium, calcium
- uremia → nephrology, dialysis decision → AKI
- seizure or post-ictal → pad the rails, suction at the bedside → seizures
- stroke → new neurological deficit
- delirium with no cause above → delirium
- meningitis / encephalitis → antibiotics now, before imaging
- 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
- hand over → GCS trend, cause found, treatments given, escalation trigger
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 Oct 2026file complaint/altered-mental-status