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Altered Mental Status

Glucose first — then work the list that kills.

LearnQuick referenceClinical practice

Your objective: explain the approach, recognize important warning signs, then test your recall.

Abbreviations explained
ACS
Acute coronary syndrome
OMI
Occlusion myocardial infarction
ECG
Electrocardiogram
PE
Pulmonary embolism
POCUS
Point-of-care ultrasound
QTc
QT interval corrected for heart rate
LBBB
Left bundle branch block
RBBB
Right bundle branch block
hs-cTn
High-sensitivity cardiac troponin
CTA
Computed tomography angiography
ICU
Intensive care unit
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The jobGlucose first — then work the list that kills.

  1. Glucose and oxygen before the mnemonic.
  2. Treat reversible causes while you work AEIOU-TIPS.
  3. Give thiamine with dextrose — never delay glucose.
  4. In the elderly, an acute change from baseline is delirium with a driver, not “UTI until proven otherwise.”

AMS is a final common pathway: check glucose and oxygen immediately, then run a broad differential (AEIOU-TIPS) while treating reversible causes.

In the elderly, any acute change from baseline is delirium until proven otherwise — and delirium always has a driver.

Hypoglycemia / hyperglycemic crises Critical

Key: Bedside glucose in every AMS patient — before anything else. Never delay dextrose for thiamine.

Hypoxia / hypercapnia Critical

Key: SpO₂, VBG; think CO₂ narcosis in COPD.

Stroke / intracranial hemorrhage Critical

Key: Sudden onset, focal signs, anticoagulation — non-contrast CT now. IV tenecteplase or alteplase if eligible within 4.5 h; mechanical thrombectomy up to 24 h in selected patients, including some large-core and basilar occlusions (2026 AHA/ASA) — not a rigid 6-hour wall.

SAH Critical

Key: Sudden headache + collapse; CT then LP or CTA as indicated.

Meningitis / encephalitis Critical

Key: Fever, meningismus — empiric therapy must not wait on imaging.

Wernicke encephalopathy Critical

Key: Alcohol use/malnutrition — give thiamine with (or immediately after) glucose; do not withhold glucose.

Toxic ingestion (CO, TCA, salicylates, opioids) Critical

Key: Pupils, skin, ECG (QRS widening), anion gap, temperature. Cherry-red skin is an unreliable CO sign — use CO-oximetry.

Severe hyponatremia / hyperammonemia / uremia Emergent

Key: Metabolic catastrophes — labs before labels.

Delirium from infection / retention / medications Common

Key: Find the driver; “UTI” alone is an overused explanation in the elderly (asymptomatic bacteriuria is not a diagnosis).

Tick what your patient has — the banner updates as you go.

Baseline cognition and tempo of change (family, care home, EMS)

Medications

sedatives, anticholinergics, insulin, anticoagulants

Substance use, alcohol, psychiatric history, toxin access

Trauma/falls — subdural in the elderly, especially if anticoagulated

Fever, headache, seizure activity, end-organ disease

GCS + focused neuro

pupils, focal signs, meningismus

Glucose and SpO₂ at the bedside — mandatory first steps

Skin

needle tracks, rash, pallor; do not rely on cherry-red colour for CO

Breath odor

hepatic, ketotic, alcohol, uremic

Trauma stigmata

hemotympanum, raccoon eyes, scalp hematoma

Bedside

  • Glucose, SpO₂, temperature, VBG
  • ECG (TCA patterns, ischemia, dysrhythmia)
  • POCUS for free fluid / obvious cranial findings as trained

Labs

  • Electrolytes (Na, Ca), renal and hepatic panels; ammonia if liver disease
  • Lactate, CBC, coagulation, targeted toxicology, TSH
  • CO-oximetry if CO is possible

Imaging

  • Non-contrast head CT before LP when indicated (focal signs, anticoagulation, depressed GCS, papilledema)
  • CXR; LP and EEG per clinical picture
Medication safety reminder

Use this as a first-pass prompt; verify all medications, doses, concentrations, contraindications, weight, pregnancy status, and local protocols before administration.

Check indication, allergy, route, renal/hepatic risk, interactions, monitoring, and local formulary.

Discharge

  • Baseline mental status restored, reversible cause treated, safe environment with reliable observers (e.g., resolved simple hypoglycemia with a plan).

Admit

  • Delirium of unclear cause, treated infection under observation, uncorrected metabolic derangement.

ICU / stroke pathway

  • Coma, airway compromise, status epilepticus, severe intoxication, massive ICH, fulminant sepsis, large-vessel occlusion within the EVT window.

Use objective reassessment and the local pathway.

Before the next decision · reassess and hand over

Use these learning prompts with the presentation’s pathway. They are not discharge criteria.

  1. Reassess: compare symptoms, observations and examination with the initial assessment and response to treatment.
  2. Warning signs for Altered Mental Status:
    • Falling GCS or new focal neurology
    • Hypoglycemia or hypothermia
    • Meningismus, fever, or new seizure
    • Suspected overdose with QRS widening or absent gag reflex
    • Anticoagulation + head injury
    • Hypercapnia or acidosis on VBG
  3. Reconsider: check unresolved findings and alternative explanations, including the pitfalls below.
  4. Escalate: communicate deterioration, uncertainty or needs beyond the current setting.
  5. Plan the transition: identify outstanding results, responsibility for follow-up, patient understanding and specific return advice.
Review this presentation’s disposition pathway →Practice a handover →

Clinical Pearls

  • Glucose and oxygen before the mnemonic.
  • Never delay dextrose for thiamine — give them together.
  • “UTI causing AMS” is overcalled; asymptomatic bacteriuria is not a diagnosis (IDSA).
  • A changing elderly patient without a clear fall still has a subdural until you look.

Pitfalls

  • “UTI causing AMS” is overcalled — keep looking for the true driver (IDSA: do not treat asymptomatic bacteriuria).
  • Never delay dextrose for thiamine. Give thiamine concurrently; a single glucose bolus has not been shown to precipitate Wernicke. Prolonged carbohydrate loads without thiamine can.
  • Subdurals in the elderly can be progressive confusion “without trauma”.
  • Hypothermia masks toxidromes and infection signs.
  • Post-ictal states normalize — image when they don’t.
PRACTICE REFRESHER

Rapid recall

Test your first action and the dangerous diagnoses before revealing the answer.

01 · First move

Before you scroll, what needs to happen first?

02 · Immediate threats

Name at least two diagnoses that cannot wait.

PRIVATE TO THIS DEVICE

Your learning note

Capture a weak point, a teaching pearl, or a question to take to your next shift.

Review schedule starts when marked reviewed
Coma & Depressed LOCSeizuresPoisoning & OverdoseSyncopeFever & SepsisHeat Stroke & HypothermiaDKA, HHS & Adrenal CrisisECG Guide

Selected guidance · source check 2026-09-07. These 2 source links support selected teaching points, not a complete review of this topic. Check population, setting and local protocol before applying a recommendation.

  • Rosen’s Emergency Medicine, 10th ed. (2023) — altered mental status & delirium
  • Han JH, Wilber ST. Altered mental status in older patients in the emergency department. Clin Geriatr Med.
  • 2026 AHA/ASA acute ischemic stroke guideline; IDSA asymptomatic bacteriuria
  • Donnino et al., Ann Emerg Med 2007; Schabelman & Kuo, J Emerg Med 2012 — thiamine/glucose sequence
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