Stethopedia | Approach

Approach to

Altered Mental Status

Check glucose and vitals, treat what can't wait, use collateral to define the change from baseline, then hunt the cause: metabolic, infection, drugs, primary CNS. Call it multifactorial delirium only once those are excluded.

  1. Acute change from baseline in arousal, attention or thinking
  2. ABCs, vitals, glucose; collateral: baseline, last known well, med changes12
  3. Exam: GCS, attention, pupils, focal signs, meningismus; CAM or 4AT1,2
  4. Any emergency feature?

Emergency: treat now, then find the cause12

  • Glucose <4 mmol/L: dextrose now ± thiamine3,4,9
  • Airway at risk or GCS ≤8: call ICU
  • Focal deficit, unequal pupils: code stroke
  • Fever, stiff neck: cultures, dex + antibiotics6
  • Seizure ≥5 min: benzodiazepine5
  • Miosis, slow RR: naloxone12

→ Lorazepam 4 mg IV or midazolam IM; naloxone 0.04 mg IV, titrate5,12

If not: which cause category?

CausesCluesWorkupManagement

Metabolic

  • Hypoglycemia, hypoxia, hypercapnia
  • Wernicke (thiamine deficiency)
  • Na, Ca, uremia, liver, endocrine
  • Asterixis, multifocal myoclonus12
  • Eye palsy, ataxia, EtOH, poor diet4
  • Hypoglycemia can mimic stroke
  • Lytes, Ca, creatinine, LFTs, VBG12
  • TSH, ammonia, cortisol if needed
  • Thiamine 200 mg IV TID if Wernicke4
  • Low Na + symptoms: 3% NaCl11
  • Lactulose for liver; NIV for CO2

Infection

  • Meningitis, encephalitis
  • Sepsis
  • Pneumonia; UTI only if GU symptoms10
  • Fever, headache, stiff neck, rash
  • New seizure; immunosuppressed
  • Blood cultures, CXR, lactate10
  • CT 1st: focal, seizure, GCS <10, immunosupp.6
  • Meningitis: dex + antibiotics before CT6
  • Acyclovir if encephalitis possible

Drugs & toxins

  • Opioid or sedative toxicity
  • Alcohol or benzo withdrawal
  • Serotonin syndrome, NMS, anticholinergics
  • Drugs started, stopped or missed12
  • Toxidrome: pupils, skin, HR, temp
  • Med review; tox screen, levels
  • Acetaminophen, salicylate; ECG (QTc)
  • Stop deliriogenic drugs8
  • Benzos only for withdrawal, seizure8

Primary CNS

  • Stroke, ICH, herniation
  • Nonconvulsive status epilepticus
  • Post-ictal, subdural, PRES
  • Focal deficit, gaze deviation, pupils
  • Unexplained coma; subtle twitching7
  • CT ± CTA head and neck12
  • Urgent EEG if coma unexplained7
  • MRI if CT negative or subacute12
  • Code stroke; bleed: neurosurgery12
  • Status: benzo, then ASM load5,12
  • HOB 30°; reverse anticoagulant12

Delirium, multifactorial

  • Age, dementia, sensory loss + insult12
  • Retention, constipation, pain
  • No single cause once 1–4 excluded12
  • Hypoactive: quiet, sleepy, missed
  • Rescreen daily: CAM or 4AT1,2
  • Bladder scan; bowel and pain review12
  • Reorient, glasses, sleep, walk8,12
  • Antipsychotic only if unsafe8,12
  • Avoid benzos and restraints8

Can't-miss cause Superscripts link to the references below.

References

  1. Wong CL, Holroyd-Leduc J, Simel DL, Straus SE. Does this patient have delirium?: value of bedside instruments. JAMA. 2010;304:779–786. PubMed 20716741
  2. Tieges Z, Maclullich AMJ, Anand A, et al. Diagnostic accuracy of the 4AT for delirium detection in older adults: systematic review and meta-analysis. Age Ageing. 2021;50:733–743. PubMed 33951145
  3. Diabetes Canada Clinical Practice Guidelines Expert Working Group; Lega IC, Yale JF, Chadha A, et al. Hypoglycemia in adults. Can J Diabetes. 2023;47:548–559. PubMed 37821214
  4. Galvin R, Bråthen G, Ivashynka A, et al. EFNS guidelines for diagnosis, therapy and prevention of Wernicke encephalopathy. Eur J Neurol. 2010;17:1408–1418. PubMed 20642790
  5. Glauser T, Shinnar S, Gloss D, et al. Evidence-based guideline: treatment of convulsive status epilepticus in children and adults: report of the Guideline Committee of the American Epilepsy Society. Epilepsy Curr. 2016;16:48–61. PubMed 26900382
  6. van de Beek D, Cabellos C, Dzupova O, et al. ESCMID guideline: diagnosis and treatment of acute bacterial meningitis. Clin Microbiol Infect. 2016;22 Suppl 3:S37–S62. PubMed 27062097
  7. Towne AR, Waterhouse EJ, Boggs JG, et al. Prevalence of nonconvulsive status epilepticus in comatose patients. Neurology. 2000;54:340–345. PubMed 10668693
  8. Marcantonio ER. Delirium in hospitalized older adults. N Engl J Med. 2017;377:1456–1466. PubMed 29020579
  9. Schabelman E, Kuo D. Glucose before thiamine for Wernicke encephalopathy: a literature review. J Emerg Med. 2012;42:488–494. PubMed 22104258
  10. Nicolle LE, Gupta K, Bradley SF, et al. Clinical practice guideline for the management of asymptomatic bacteriuria: 2019 update by the Infectious Diseases Society of America. Clin Infect Dis. 2019;68:e83–e110. PubMed 30895288
  11. Spasovski G, Vanholder R, Allolio B, et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Eur J Endocrinol. 2014;170:G1–G47. PubMed 24569125
  12. Gay E, Levy N, eds. Altered Mental Status; CNS Emergencies; Seizures; Delirium; Opioid Use Disorder. In: Department of Medicine Housestaff Manual, 30th ed. 2024:193, 198–199, 204, 212.

For education only; not a substitute for clinical judgment or local protocols. Where sources differ, the flowchart follows the current guideline.

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