Before We Start
What is altered mental status and why is it dangerous?
Altered mental status (AMS) is any change from a patient's normal level of consciousness or cognitive function. This can range from mild confusion and disorientation all the way to complete unresponsiveness.
AMS is dangerous for two reasons: First, the patient cannot protect themselves — they may fall, remove lines, or make unsafe decisions. Second, AMS is almost always a symptom of an underlying problem, not a diagnosis itself. Finding and treating that underlying cause is the priority.
The critical mistake nurses make is assuming AMS is neurological — a stroke, head injury, or psychiatric condition — when in fact it might be hypoglycemia (low blood sugar) that can be reversed in minutes with glucose.
💡 The Memory Trick
AEIOU TIPS — The vowels come first (AEIOU), then TIPS.
Think of it as: you're "giving tips" about the vowels — the framework gives you tips on where to look for the cause of AMS.
Nine categories. Systematic. Miss none.
The Nine Causes
AEIOU TIPS — each cause explained
A — Alcohol / Drugs
Intoxication OR withdrawal — both cause AMS
Alcohol and drug intoxication are obvious causes of altered mental status. But withdrawal can be equally dangerous and is often missed.
Alcohol withdrawal: Can begin 6–24 hours after the last drink. Progresses from tremors and anxiety to seizures (12–48 hours) to delirium tremens (DTs, 48–72 hours) — which is life-threatening.
Assess: CIWA scale (Clinical Institute Withdrawal Assessment for Alcohol) to quantify severity. History of alcohol use disorder. Last drink time.
💊 A hospitalized patient who suddenly becomes confused and agitated on day 2 of admission may not be "just confused" — they may be in alcohol withdrawal. Ask about alcohol use on admission.
E — Endocrine/Electrolytes
Thyroid, adrenal, electrolyte imbalances
The endocrine system and electrolytes have profound effects on brain function.
Thyroid: Hypothyroidism (myxedema coma) → extreme lethargy, hypothermia, bradycardia. Hyperthyroidism (thyroid storm) → agitation, fever, tachycardia, confusion.
Electrolytes:
• Sodium — hyponatremia (low Na+) causes confusion and seizures; hypernatremia causes irritability and altered consciousness
• Calcium — hypercalcemia causes fatigue, confusion ("bones, groans, moans, and psychic overtones")
• Magnesium — both high and low levels affect neurological function
💊 Check the BMP (basic metabolic panel) early — sodium and glucose are the most common electrolyte causes of AMS.
I — Insulin (Blood Sugar)
Hypoglycemia is the most reversible cause of AMS — check it first
Hypoglycemia (low blood sugar) is one of the most common and most treatable causes of AMS. The brain runs almost exclusively on glucose — when glucose drops, brain function deteriorates rapidly.
Signs of hypoglycemia: Confusion, diaphoresis (sweating), tremors, tachycardia, pallor, irritability, loss of consciousness.
Critical rule: Check a fingerstick blood glucose (FSBG) on EVERY patient with AMS. Normal blood glucose is 70–110 mg/dL. Less than 70 = hypoglycemia. Less than 50 = severe, act immediately.
Hyperglycemia (high blood sugar — DKA or HHS) also causes AMS — gradually developing confusion, fruity breath, polyuria, dehydration.
💊 AMS + diaphoresis + tachycardia = check glucose NOW. If below 70 and patient is conscious — give 4 oz of juice or glucose tabs. If unconscious — give D50 IV per order or glucagon IM.
O — Overdose / Oxygen
Too much of a substance OR not enough oxygen
Overdose: Medication overdose or toxic ingestion. Key toxidromes to know:
• Opioid overdose: pinpoint pupils, respiratory depression, decreased LOC → give naloxone (Narcan)
• Benzo overdose: similar to opioid but pupils normal → give flumazenil (use cautiously)
• Stimulant overdose: agitation, tachycardia, hypertension, dilated pupils
• Anticholinergic: "dry as a bone, red as a beet, hot as a hare, blind as a bat, mad as a hatter"
Oxygen (hypoxia): The brain is exquisitely sensitive to oxygen deprivation. SpO2 below 90% causes restlessness and confusion; further drops cause unconsciousness. Check SpO2 on every AMS patient.
💊 Opioid OD = pinpoint pupils + slow breathing + decreased LOC. Give naloxone IM or intranasal if IV access not immediately available.
U — Uremia
Kidney failure causing toxic buildup in the blood
Uremia occurs when the kidneys fail and waste products (urea, creatinine, and others) accumulate in the bloodstream. These toxins cross the blood-brain barrier and cause neurological symptoms.
Signs of uremic encephalopathy: Confusion, asterixis (flapping tremor of outstretched hands — "liver flap"), drowsiness, seizures, coma in severe cases.
Also consider: Liver failure causes hepatic encephalopathy — similar presentation, also causes asterixis, elevated ammonia levels.
Assess: BUN and creatinine levels, urine output (oliguria or anuria), edema, history of CKD or dialysis.
💊 Asterixis (flapping hand tremor) = think uremia or hepatic encephalopathy. Ask the patient to hold their arms out and watch for the "flap."
T — Trauma
Head injury — obvious and not-so-obvious
Traumatic brain injury (TBI) is a direct cause of AMS. But trauma isn't always obvious — an elderly patient who fell and "just bumped their head" may have a subdural hematoma that develops over hours to days.
Watch for: History of fall or head impact (even minor), worsening headache, asymmetric pupils, Cushing's triad (widening pulse pressure + bradycardia + irregular respirations = increased ICP).
Subdural hematoma in elderly: Can present days to weeks after a minor injury. Classic presentation: gradual onset of confusion in an older adult with a history of a fall.
💊 An elderly patient on anticoagulants who "fell last week" and is now confused = CT head NOW. Anticoagulants make even minor head trauma dangerous.
I — Infection
Sepsis, meningitis, encephalitis — infection anywhere can cause AMS
Infection-related AMS ranges from the relatively common (UTI-related confusion in elderly patients) to the immediately life-threatening (bacterial meningitis, septic encephalopathy).
Septic encephalopathy: The most common cause of AMS in the ICU. Systemic infection triggers inflammatory responses that impair brain function. Treat the infection → treat the AMS.
Meningitis: Fever + severe headache + neck stiffness (nuchal rigidity) + photophobia + AMS = meningitis until proven otherwise. Immediate antibiotics — do NOT wait for LP results if patient is deteriorating.
UTI in elderly: Urinary tract infections in older adults often present with confusion instead of the classic urinary symptoms. Check urinalysis on every confused elderly patient.
💊 Confused elderly patient + fever + no obvious cause = check urinalysis. UTI is the most common cause of new-onset confusion in older adults.
P — Psychiatric
Psychiatric conditions — but rule out medical causes first
Psychiatric conditions — acute psychosis, severe depression, bipolar mania, schizophrenia — can all present with AMS. However, psychiatric diagnosis should only be considered after all medical causes have been ruled out.
Critical rule: Never assume a psychiatric cause for AMS until the medical workup is complete. A patient who appears "psychotic" may actually have a brain tumor, encephalitis, or be in thyroid storm.
Delirium vs. dementia: Delirium = acute onset, fluctuating, usually has a medical cause. Dementia = slow onset, progressive, stable at baseline. Delirium is a medical emergency; dementia is a chronic condition.
💊 "Medical before psychiatric" — always. Rule out medical causes first. A first-time psychotic break in a middle-aged patient with no psychiatric history needs a full medical workup.
S — Shock
Any shock state reduces cerebral perfusion
Shock is inadequate tissue perfusion. The brain is one of the first organs to show signs of impaired perfusion — AMS is an early sign of shock in many patients.
Types of shock:
• Hypovolemic — hemorrhage, dehydration (BP down, HR up, cool/clammy skin)
• Cardiogenic — heart failure, MI (same vitals as hypovolemic, but JVD and crackles present)
• Distributive — sepsis, anaphylaxis, neurogenic (warm skin in early sepsis/anaphylaxis)
• Obstructive — tension pneumothorax, cardiac tamponade
AMS + hypotension: Always think shock. Get vital signs immediately on any AMS patient.
💊 AMS + hypotension + tachycardia = shock until proven otherwise. Call for help, establish IV access, and notify the provider immediately.
✓ Quick Self-Test
Match each presentation to the most likely AEIOU TIPS cause:
1. Confused diabetic patient, diaphoretic, HR 118
2. Elderly patient admitted for pneumonia, now agitated and pulling at IV lines on day 3
3. Pinpoint pupils, respiratory rate of 6, unresponsive
4. Confused patient, BP 80/50, HR 132, pale and diaphoretic
5. Hospitalized alcoholic, trembling and seeing things on day 2
Answers:
1. Insulin (hypoglycemia) — check glucose immediately
2. Infection (UTI or hospital-acquired pneumonia) + delirium — also consider Alcohol withdrawal
3. Overdose (opioid toxidrome) — give naloxone
4. Shock (hypovolemic or septic) — establish IV access, notify provider
5. Alcohol withdrawal — CIWA assessment, benzodiazepines per protocol