No labs. No CT. No MRI. Just your eyes, your hands, a stethoscope, and a glucometer. Here's how to work an altered patient and catch the thing that's trying to kill them.
You walk in and something's off. Patient's awake and talking, but the words come out scrambled and the eyes aren't quite tracking you. Family's standing there swearing she was fine an hour ago. So now what?
In the back of a truck you don't get labs. You don't get a CT. What you've got is your eyes, your hands, a stethoscope, and a finger-stick of glucose. That's the whole kit. Field diagnosis is educated guessing at best, and I have no problem saying that out loud. The goal is to keep the guessing structured instead of throwing darts.
Your job is the same whether you're a brand-new EMR or a flight medic, and it's honestly the same job the doc has when you roll through the ED doors: find the immediate life threats and treat them. Altered mental status (AMS) is almost never the actual diagnosis. It's a symptom. And every so often it's the only thing telling you something is quietly killing your patient. AEIOU-TIPS is just a way to make yourself check the whole list instead of locking onto the easy answer and blowing past the one that matters.1
When the pressure's on, your brain wants to grab the easy story. He's just drunk. She's just confused. The mnemonic exists to slow that down long enough that the bleed hiding behind the booze on his breath doesn't skate by. It also tells you where to go. Nail the cause and you already know whether this is a stroke center, a cath lab, or just the closest ED.
Work the Easy, Lethal Stuff First
Before you start working the alphabet, do the routine stuff. Bring your bags to the patient, work them where they are, get a full set of baseline vitals with a cuff that actually fits the arm, and dig for history. If there's recent discharge paperwork lying around, grab it. A discharge summary tells you in ten seconds what you'd otherwise spend five minutes reverse-engineering out of a shoebox of pill bottles.
Then check the two things that are easiest to fix and will kill your patient the fastest:
- Hypoxia. Low SpO₂ on the pulse oximeter? Put oxygen on them. The brain is extremely sensitive to hypoxia, and oxygen is the easiest fix on this entire list.
- Hypoglycemia. Quick finger-stick on the glucometer. Treat anything under 60, and some services use 70. A reading over 250 can also explain why they are altered.
Figure out early if this is turning into a safety problem, too. If you can't keep them safe, are you going to soft-restrain, or at the medic level reach for sedation? Make that decision early instead of waiting for it to become a wrestling match in the back of the truck.
Now let's walk through the letters.
A
Alcohol. Does the guy smell like a bar? Anything on scene backing that up? Alcohol is a perfectly good reason to be acting goofy, and most of the time it is not an immediate life threat. It becomes one when they are too far gone to protect their airway or they start choking on their own vomit. The part people trip on is capacity: a drunk patient with a real medical complaint may not be legally able to refuse you. ALS can run crystalloid to help the liver and kidneys catch up.
Acidosis. Something's thrown the chemistry off. You're not sorting out exactly what without labs, but you can catch the obvious tell: fast, deep breathing while the body tries to blow off acid.
Arrhythmia. If the heart is beating too fast, too slow, or irregularly, output drops. The oxygen and glucose in the blood might be perfectly fine, but there is not enough circulation to deliver them where they need to go. Get them on the monitor early.
E
Endocrine. Think thyroid storm and Graves disease. Diabetes technically belongs here too, but it gets its own letter further down.
Electrolytes. Picture the patient who's been sweating for two days straight and dumped their sodium and potassium right along with it. That alone can scramble somebody.
Encephalopathy. The brain is swollen or not clearing toxins the way it should. You will have a hard time proving it in the field, but it stays on the list.
I
Infection and the sepsis that follows it will absolutely make somebody altered, especially older patients. A good physical exam usually turns up the source, and three sources cover most of what you will run into:
- Skin / wounds. A sore or a wound that's gone bad on them.
- Urinary tract. Big one in older women. Burning when they pee, cloudy or foul urine you can sometimes smell walking in the door, and brand-new confusion. You will see that combination constantly.
- Respiratory. A wet cough and junky lung sounds that point at pneumonia or bronchitis.
O
Oxygen. You checked this up top, so just confirm it's still holding. If it's not, a high-FiO₂ delivery mask brings the concentration up fast without burning through your whole tank.
Overdose. Look around. Pill bottles, paraphernalia, anything that says somebody was using. Then check the pupils. Pinpoint pupils lean opioid. Dilated pupils lean stimulant or another sympathomimetic. If you have an opioid picture with depressed respirations, that is your naloxone patient.2
U
Uremia is a kidney problem, not a bladder one, so don't let the name fool you. Kidneys clean the blood. When they quit, the toxins pile up and the patient goes sideways. The one you'll see over and over is the dialysis patient who skipped a session, and most of them run two or three a week. The fix is dialysis, and by the time we get called that means the hospital rather than their usual clinic.
T
Trauma. Run a real head-to-toe instead of the windshield version. Goose eggs, raccoon eyes, and bruising all matter, because a head injury is a great reason to be altered. Get suspicious any time a patient on blood thinners takes a fall. That is a brain bleed until somebody proves otherwise. For whatever external trauma you do find, keep bleeding control within arm's reach.
Temperature. If grandma is running a temp of 104 and not making sense, you have probably found your answer. The cold end counts too. Below 95 °F mentation starts to slip, and under 90 °F you are into profound hypothermia. Warming matters in both directions. An APLS reflective blanket stops further heat loss, and a portable blood and fluid warmer gets your fluids or blood up to temp before they ever hit the vein.3
Thiamine (B1). Heavy drinkers run chronically low on it, and the brain genuinely needs thiamine to function. It is a real and fixable cause of altered mentation.
I
Hypoglycemia (< 60). If they can hold their head up and swallow, oral glucose is fair game. When it's borderline but they can still sip, hand them a regular soda or some OJ through a straw. That gets roughly 50 grams of sugar in, and it is a lot harder to choke on than a tube of glucose paste shoved in their cheek. Two things I won't skip: make them eat something before they refuse, and ask yourself why they bottomed out in the first place. Skipped a meal, or is there an infection underneath burning through their sugar?4
Hyperglycemia (> 250–300). Now you're thinking DKA or HHS. Look for deep, fast Kussmaul respirations as the body tries to dump acid, along with the rest of the acidosis picture. These patients are going to the hospital.5
P
Poisoning. Carbon monoxide is the sneaky one. Gas appliances, a bad furnace, or a house fire can all produce it, and your pulse ox will read normal the whole time. Bring the four-gas meter in with you, and when smoke or CO is in the picture, use a handheld CO-oximeter that reads SpCO and SpMet so you are not guessing.6 Fire smoke also carries cyanide and hydrogen sulfide. Mixed household cleaners and organophosphates round out the list, and bleach with ammonia is the classic combination. Monitoring the air also keeps you from becoming the second patient on the call.
Psychiatric. It is real, but it is a diagnosis of exclusion. Clear the medical causes above before you call it psych.
S
Stroke. There are two kinds, a clot or a bleed. Run a Cincinnati screen for facial droop, arm drift, and speech that's slurred or coming out jumbled,7 then tack on the large-vessel clues like gaze deviation, neglect, and a dense one-sided weakness.8 A patient on blood thinners who fell and is now altered gets treated like a bleed until the hospital rules it out. Either way the destination is a stroke center. A freestanding ER cannot do much more for a stroke than we can in the field.
Seizure. Could this be a postictal patient who is still confused after seizing? Look for a seizure history or for whatever triggered it, like a fever in a kid or drugs in an adult.
Syncope. They passed out and came back around. The cause is worth chasing down.
Space-occupying lesion. A tumor or mass putting pressure where it should not be.
Shunt. A failing VP shunt lets the pressure inside the skull climb back up. You can usually feel the reservoir and tubing running down the side of the neck, and it feels like firm plastic instead of a vein. Once you have felt one you will not forget it.
Figuring out the cause is only half of it. A stroke needs a stroke center. A STEMI needs a cath lab. Uremia needs dialysis. The closest ER beats nothing, but for a handful of these the right hospital is the treatment.
The 60-Second Reference
| Letter | Think about | Field move |
|---|---|---|
| A | Alcohol, acidosis, arrhythmia | Scene survey, monitor, ALS fluids |
| E | Endocrine, electrolytes, encephalopathy | History, hydration status |
| I | Infection (skin, UTI, respiratory) | Physical exam, lung sounds, sepsis check |
| O | Oxygen, overdose | SpO₂, pupils, naloxone if indicated |
| U | Uremia / missed dialysis | Transport for dialysis |
| T | Trauma, temperature, thiamine | Head-to-toe, temp, anticoagulant history |
| I | Insulin (hypo / hyperglycemia) | Glucometer, oral glucose or transport |
| P | Poisoning, psychiatric | Four-gas meter, exclude organic causes |
| S | Stroke, seizure, syncope, shunt | Stroke screen, LVO clues, right destination |
None of this replaces your judgment or your local guidelines. It just gives them a track to run on. Work the sweep, treat what you turn up, and get the patient to the place that can actually finish the job.
Frequently Asked Questions
What does AEIOU-TIPS stand for?
Alcohol/Acidosis/Arrhythmia, Endocrine/Electrolytes/Encephalopathy, Infection, Oxygen/Overdose, Uremia, Trauma/Temperature/Thiamine, Insulin, Poisoning/Psychiatric, and Stroke/Seizure/Syncope/Space-occupying lesion/Shunt. It's a structured checklist for the differential of altered mental status.
What are the two things to fix first in an altered patient?
Hypoxia and hypoglycemia. They are the O and the I of the mnemonic, and both can be identified and corrected in minutes, or kill your patient if missed. Check SpO₂ and a finger-stick glucose before anything else.
Can BLS providers treat altered mental status?
Yes. BLS care covers the reversible basics: oxygen for hypoxia, oral glucose for a hypoglycemic patient who can protect their airway, scene and air safety, and fast transport to the right destination. Higher levels add IV access, advanced airway, cardiac monitoring, and medications.
What blood glucose counts as low or high?
Most services treat below 60 mg/dL (some use 70) as actionable hypoglycemia. Above 250–300 mg/dL with altered mentation raises concern for DKA or HHS. Always follow your local clinical guidelines.
Is altered mental status always an emergency?
Treat it as one until proven otherwise. AMS can be the only sign of a stroke, sepsis, overdose, or hemorrhage in progress. Working AEIOU-TIPS is how you confirm or rule out the life threats.
Carry the Right Tools Into Every Call
From glucometers and pulse oximetry to airway and monitoring equipment, Pacific Biomedical equips prehospital, neonatal, and acute care teams across the country. Field-tested gear, clinician-backed support.
Browse the catalog →References
- Nickson C. Coma DDx. Life in the Fast Lane. Updated July 7, 2024. Accessed June 21, 2026. https://litfl.com/coma/
- Williams K, Lang ES, Panchal AR, et al. Evidence-based guidelines for EMS administration of naloxone. Prehosp Emerg Care. 2019;23(6):749-763. doi:10.1080/10903127.2019.1597955
- Brown DJA, Brugger H, Boyd J, Paal P. Accidental hypothermia. N Engl J Med. 2012;367(20):1930-1938. doi:10.1056/NEJMra1114208
- National Association of EMS Physicians. Can you leave them be? A review of the recommendations of hypoglycemia treat and release protocols. NAEMSP. Published June 30, 2018. Accessed June 21, 2026. https://naemsp.org/2018-6-30-can-you-leave-them-be-a-review-of-the-recommendations-of-hypoglycemia-treat-and-release-protocols/
- Kitabchi AE, Umpierrez GE, Miles JM, Fisher JN. Hyperglycemic crises in adult patients with diabetes. Diabetes Care. 2009;32(7):1335-1343. doi:10.2337/dc09-9032
- Bozeman WP, Myers RA, Barish RA. Confirmation of the pulse oximetry gap in carbon monoxide poisoning. Ann Emerg Med. 1997;30(5):608-611. doi:10.1016/S0196-0644(97)70077-5
- Kothari RU, Pancioli A, Liu T, Brott T, Broderick J. Cincinnati Prehospital Stroke Scale: reproducibility and validity. Ann Emerg Med. 1999;33(4):373-378. doi:10.1016/S0196-0644(99)70299-4
- Pérez de la Ossa N, Carrera D, Gorchs M, et al. Design and validation of a prehospital stroke scale to predict large arterial occlusion: the Rapid Arterial Occlusion Evaluation scale. Stroke. 2014;45(1):87-91. doi:10.1161/STROKEAHA.113.003071
This article is intended for educational purposes for trained EMS professionals and does not replace local protocols, medical direction, or formal clinical training. Always practice within your scope and your service's current clinical guidelines.
