Nursing care
AEIOU TIPS mnemonic: causes of altered mental status and what to check first
Written and reviewed by Kevin Patel, MSN, RN, CCRN · 4 min read · Updated November 2026
Short answer
AEIOU TIPS lists causes of altered mental status: alcohol; epilepsy, endocrine, electrolytes or encephalopathy; insulin; oxygen or opiates; uremia; trauma or temperature; infection; poisoning or psychosis; and shock, stroke or a space-occupying lesion. It is a cause checklist, not a priority order. Airway, breathing, circulation and a bedside glucose come before working through the letters.
What AEIOU TIPS stands for
Using the International Emergency Medicine Education Project version: A is alcohol. E covers epilepsy, endocrine disease, electrolytes and encephalopathy. I is insulin, meaning low or high blood glucose. O is oxygen, for hypoxia, and opiates. U is uremia from kidney failure. These vowels mostly describe body-wide toxic and metabolic problems.
T is trauma and temperature extremes. The second I is infection, from sepsis to meningitis. P is poisoning and psychosis. S is shock, stroke, subarachnoid hemorrhage and space-occupying lesions such as tumors. Other references swap a few words, for example overdose for O or psychogenic for P, but the categories stay much the same.
When nurses use it
AEIOU TIPS is most useful when a client is newly confused, drowsy or unresponsive and the cause is not obvious. On a ward this might be a post-operative older adult, a client with diabetes who skipped a meal, or someone with kidney disease who missed dialysis. The mnemonic prompts the nurse to gather the data that narrows the list.
That data is concrete: vital signs including temperature and oxygen saturation, a fingerstick glucose, a Glasgow Coma Scale score, pupils, recent medications, alcohol history and recent labs. MSD Manuals notes that in older adults, relatively minor problems such as dehydration or a urinary tract infection can alter consciousness, so the I for infection deserves real attention.
Worked scenario: the confused client on day two
Hypothetical scenario, not a real exam item: a 78-year-old client with type 2 diabetes is two days after hip surgery. At 0300 she is confused, sweaty and tremulous, pulling at her IV. Options: reorient her and document probable delirium, request a sedative, check a fingerstick blood glucose, or notify the provider to arrange a head CT.
Checking the glucose is the best first action after confirming she is breathing adequately. Hypoglycemia is an emergency, and the iEM text notes it can be ruled out in seconds. Labeling her delirious is tempting because of her age and surgery, but delirium has a cause to find. Sedation could hide hypoxia or low glucose.
Where AEIOU TIPS misleads
The order of letters has nothing to do with urgency. Insulin sits third and stroke sits last, yet glucose is the fastest check and stroke is among the most time-critical causes. MSD Manuals sets out the order of care: secure airway, breathing and circulation, measure glucose at the bedside, give thiamine before glucose, and give naloxone if opioid overdose is suspected.
The list also suggests one cause per client. MSD Manuals notes that several causes often coexist, such as an infection plus a sedating drug plus dehydration. It does not separate structural from metabolic problems either. In toxic and metabolic coma, pupil responses are often preserved until late, while structural lesions tend to affect the pupils early.
Related exam trap: blaming psychosis or age
P includes psychosis, and NCLEX-style distractors exploit that. A confused client with a psychiatric history may still be hypoglycemic, hypoxic or septic. Medical causes are worked through first, and psychiatric explanations come after physical ones have been looked for. The same goes for older adults: sudden confusion is a change to report, not a feature of age.
The other trap is treating the behavior instead of the cause. Restraints or sedatives may be ordered for safety, but they come after checking oxygen saturation, glucose and vital signs. Choose the answer that gathers objective data or treats a reversible cause, and save reorientation for once the client is safe.
Sources and further reading
International Emergency Medicine Education Project: Altered Mental Status. AEIOU TIPS letter expansion, ABC-first approach, checking glucose immediately because hypoglycemia can be ruled out in seconds, and oxygen saturation targets.
MSD Manual Professional Edition: Overview of Coma and Impaired Consciousness. Structural vs nonstructural causes, ABCs, bedside glucose, thiamine before glucose, naloxone for suspected opioids, pupil responses, minor causes in older adults, coexisting causes.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our neurological practice questions are the closest set to what this page covers.
Common questions
What does AEIOU TIPS stand for?
Alcohol; epilepsy, endocrine, electrolytes or encephalopathy; insulin; oxygen or opiates; uremia; trauma or temperature; infection; poisoning or psychosis; and shock, stroke, subarachnoid hemorrhage or a space-occupying lesion. Versions vary slightly between sources.
What are causes of altered mental status?
They fall into structural problems such as head injury, bleeding, stroke or tumor, and nonstructural problems such as low glucose, low oxygen, drugs, alcohol, infection, kidney failure or electrolyte changes. In older adults, dehydration or a urinary tract infection can be enough.
What should the nurse check first in a newly confused client?
Airway, breathing and circulation, then a bedside glucose, which is fast and treatable. Oxygen saturation, temperature, a Glasgow Coma Scale score and pupils follow, along with a review of recent medications.