Compare conditions

Put any two — or three — conditions side by side, adult or pediatric, to spot the look-alike differences fast, row by row.

Hypothermia

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In one line

·The body's core temperature drops below 35°C (95°F), and the machinery that makes and keeps heat cannot keep up.

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Normal physiology

·Your body keeps its core at 37°C (98.6°F) because that is the only temperature where enzymes, cells, and organs work right. The hypothalamus (a control center deep in your brain) reads blood temperature every second and fires two main tools to keep you warm: shivering (your muscles shake fast to burn fuel and make heat) and vasoconstriction (blood vessels squeeze tight so warm blood stays near your heart, lungs, and brain instead of leaking out through your skin). Keep that picture in your head, because every weird finding in hypothermia only makes sense as a change from that normal job.

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What goes wrong

·Hypothermia happens when heat leaves your body faster than your muscles and metabolism can make it. The most common cause is cold exposure (being outside in freezing air, falling into icy water, or wearing wet clothes in the wind). Water pulls heat out of your body 25 times faster than air at the same temperature, so immersion hypothermia happens fast. But hypothermia can also happen indoors if something inside your body breaks the heat-making machinery: sepsis (overwhelming infection that drops your metabolism), hypothyroidism (low thyroid hormone, so your cells burn fuel slowly), low blood sugar (hypoglycemia) (low blood sugar, so your muscles have no fuel to shiver), malnutrition (no fuel reserves), alcohol (which dilates blood vessels so heat pours out through your skin and also clouds judgment so you do not feel the cold), or trauma (which can damage the hypothalamus or spinal cord). Once shivering stops around 32°C, the body cannot save itself — your muscles are out of fuel and oxygen, and now you are just a passive object losing heat.

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Hallmark signs

·Core body temperature below 95°F (35°C)
·Shivering at first, then shivering stops
·Confusion, slurred speech, or acting drunk
·Heart rate slows down (bradycardia)
·Breathing slows and gets shallow
·J waves (Osborn waves) on the ECG
·Skin feels ice-cold and may look pale, blue, or waxy
·Muscles feel stiff and movements are clumsy

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Red flags · escalate now

·Core temperature below 90°F (32°C) — severe hypothermia with high risk of deadly heart rhythms
·Confusion, can't stay awake, or doesn't respond when you shake them — brain is shutting down
·Shivering has stopped but the person is still very cold — body can't fight back anymore
·Heart rhythm is chaotic or very slow (ventricular fibrillation or severe a slow heart rate (bradycardia)) — can stop any second
·Breathing is barely noticeable or has stopped — needs rescue breaths and advanced warming right away

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Workup

·Core body temperature using esophageal, rectal, or bladder thermometer (low-reading probe)
·12-lead electrocardiogram (ECG)
·Serum potassium
·Arterial blood gas (ABG) without temperature correction
·Serum glucose
·Thyroid-stimulating hormone (TSH) and free T4
·Toxicology screen (urine and serum) and blood alcohol level
·Complete blood count (CBC), metabolic panel, and coagulation studies (PT, aPTT)

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Treatment

·Remove all wet clothing and move the person to a warm environment (room temperature 21–24°C or 70–75°F); for mild hypothermia (32–35°C), use passive external rewarming with blankets; for moderate (28–32°C), add forced-air warming blankets (Bair Hugger) at 40–42°C
·Give warm intravenous fluids (normal saline or lactated Ringer's heated to 40–42°C or 104–108°F) and deliver warm humidified oxygen (42–46°C or 108–115°F) through a mask or endotracheal tube
·Handle the person extremely gently — no rough movement, no vigorous chest compressions unless absolutely needed, and avoid unnecessary procedures like central line insertion until the core is warmer
·For severe hypothermia (core below 28°C or 82°F with cardiac arrest or ventricular fibrillation), initiate extracorporeal life support — either ECMO or cardiopulmonary bypass — as soon as possible
·Do NOT give standard ACLS medications (epinephrine, amiodarone, lidocaine) or attempt defibrillation more than once until core temperature is above 30°C (86°F); cold hearts do not respond to these drugs
·Identify and treat the upstream cause: give intravenous antibiotics (e.g., ceftriaxone and vancomycin) for sepsis, intravenous levothyroxine 200–400 mcg plus hydrocortisone 100 mg for myxedema coma, dextrose 25–50 g IV for low blood sugar (hypoglycemia), thiamine 100 mg IV before glucose if alcohol use or malnutrition is suspected
·Rewarm slowly and continuously until core temperature reaches at least 32–35°C (90–95°F) and vital signs stabilize; do not stop rewarming efforts in cardiac arrest until core is above 32°C — continue CPR during rewarming

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NCLEX trap

·In hypothermia, people can look dead but are not. The saying is: 'Nobody is dead until warm and dead.' Always start CPR and warm the person first. A cold brain can survive much longer without oxygen than a normal-temperature brain.
·If they are confused or unresponsive, hot drinks can go into the lungs instead of the stomach and cause drowning or burns. In moderate to severe hypothermia, give warm IV fluids (saline heated to 40–42°C) and warm humidified oxygen instead. Let them rewarm gently and safely.
·Rough handling or friction can trigger ventricular fibrillation (a deadly chaotic heart rhythm) in a cold heart. The heart muscle is extremely irritable when cold. Handle them like glass — move gently, remove wet clothes carefully, and let controlled warming do the work.
·A slow heart rate (bradycardia) in hypothermia is normal and expected — the cold body needs less oxygen, so the heart slows down to match. Drugs like epinephrine and atropine do not work well in a cold heart and can trigger dangerous rhythms. Rewarm first, support with gentle CPR if needed, and let the heart speed up naturally as temperature rises.
·In hypothermia, keep doing CPR for an hour or more — sometimes several hours. The cold brain and heart can survive much longer without oxygen than normal because cold slows down cell death. Warm the person to at least 32–35°C before you even think about stopping. Many people have walked out of the hospital alive after hours of CPR in hypothermia.
·The Osborn J wave (also called a J point elevation) is a signature ECG finding of hypothermia, not a heart attack. It is a small hump right after the QRS complex and shows the heart muscle is cold. It goes away as the body warms up. Do not confuse it with ST elevation or other acute coronary syndromes. Focus on gentle rewarming, not cardiac interventions.

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