Compare conditions

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

Myxedema Coma

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In one line

·The thyroid has stopped working, and the patient's whole body is shutting down.

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Normal physiology

·The thyroid gland makes thyroid hormone (mainly T4, which the body turns into the active form T3). Thyroid hormone tells every cell in the body how fast to burn fuel and make energy. It keeps your core temperature steady, drives your heart to beat at the right speed and strength, tells your brain to keep breathing, and keeps your brain cells working sharply. The adrenal glands make cortisol, which helps the body handle stress like infection, injury, or surgery. These two systems work together to keep the body running smoothly.

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What goes wrong

·The thyroid stops making enough hormone (or someone stops taking their thyroid pill), and then a big stress — like infection, cold, surgery, a sedating drug, or a heart attack — pushes the body over the edge into shutdown. Often the adrenal glands fail at the same time and cannot make enough cortisol to handle the stress.

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Hallmark signs

·Very low body temperature (often below 95°F)
·Extremely slow or confused thinking, sometimes completely unresponsive
·Very slow heart rate and low blood pressure
·Breathing is slow and shallow
·Skin looks puffy, thick, and smooth, especially around the eyes and hands
·Hair is dry, coarse, and brittle; outer third of eyebrows may be thin or missing
·Tongue looks thick and voice sounds hoarse or deep
·Unable to urinate much or at all, belly may feel swollen

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Red flags · escalate now

·Body temperature below 95°F (hypothermia)
·Breathing becomes very slow or stops (respiratory failure)
·Completely unresponsive or unable to wake up (coma)
·Heart rate under 50 beats per minute with dangerously low blood pressure (shock)
·Recent infection, surgery, cold exposure, or suddenly stopped taking thyroid medicine

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Workup

·Thyroid-stimulating hormone (TSH) and free thyroxine (free T4)
·Serum cortisol (random or morning level)
·Serum sodium
·Arterial blood gas (ABG)
·Complete blood count (CBC)
·Blood glucose
·Chest X-ray
·Electrocardiogram (ECG)

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Treatment

·Give IV hydrocortisone 100 mg immediately, then 50-100 mg every 6-8 hours
·Give IV levothyroxine (T4) 200-400 mcg loading dose, then 50-100 mcg IV daily until the patient can swallow pills
·Some centers add IV liothyronine (T3) 5-20 mcg loading dose, then 2.5-10 mcg every 8 hours for 1-2 days
·Passive rewarming with blankets; do NOT use heating blankets, warm IV fluids, or forced-air warmers
·Give IV normal saline or hypertonic saline (3%) slowly if sodium is very low; raise sodium no faster than 6-8 mEq/L in 24 hours
·Treat the trigger: IV antibiotics for infection, stop sedatives or opioids, support breathing if CO2 is high
·Intubate and start mechanical ventilation if PaCO2 > 60 mmHg or the patient cannot protect the airway

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NCLEX trap

·In myxedema coma, start thyroid hormone slowly and carefully. A too-fast dose can trigger a heart attack or dangerous heart rhythm, especially in older adults whose hearts are already weak. The correct approach: give IV levothyroxine (the active thyroid hormone) as a loading dose (usually 200–400 mcg), then switch to a lower daily dose (50–100 mcg). The body needs time to wake up safely.
·Warm a myxedema coma patient slowly and gently using passive warming—regular blankets and a warm room. Fast, aggressive heating (like heat lamps or heating blankets cranked high) can widen the blood vessels suddenly, dropping blood pressure dangerously because the weak heart cannot pump enough blood to fill them. Let the body temperature climb naturally as the thyroid hormone kicks in—usually 0.5–1°C per hour is safe.
·In myxedema coma, pouring in IV fluid alone will not fix low blood pressure because the real problem is the shut-down heart and the body's broken control system. The heart muscle is too weak to pump harder, and the blood vessels are too relaxed. What the patient needs: IV hydrocortisone (to replace missing stress hormone) and IV levothyroxine (to restart the body's engine). Give fluids carefully—too much can flood the lungs because the heart cannot handle the extra load.
·The confusion in myxedema coma is from the brain running in extreme slow motion without thyroid hormone. Thyroid hormone powers every brain cell, and when it drops to almost zero, the brain shuts down—thinking gets foggy, then the patient stops responding. A head CT scan will come back normal because there is no stroke or bleed. Treat the real cause: give IV levothyroxine and IV hydrocortisone. The brain will wake up as the hormone levels climb, usually over 12–48 hours.
·In myxedema coma, always give IV hydrocortisone (a steroid stress hormone made by the adrenal glands) before or at the same time as thyroid hormone. Here is why: the thyroid and the pituitary gland (the brain's control tower) work together. When the pituitary fails, it often shuts down both thyroid hormone and the signal to the adrenal glands (ACTH). If you give thyroid hormone first, it speeds up the body suddenly, and the missing cortisol cannot keep up—blood pressure crashes, and the patient can die. Safe order: hydrocortisone 100 mg IV immediately, then levothyroxine 200–400 mcg IV, then hydrocortisone 50–100 mg IV every 6–8 hours until you are sure the adrenal glands are working.
·Myxedema coma is a life-or-death emergency—patients can die within hours. Do not wait for imaging or biopsies. Start treatment immediately based on the clinical picture (very low body temperature, confusion, puffy skin, slow heart, slow breathing) and send a blood test for TSH and free T4 right away, but do not delay the medicine while waiting for the results. You can figure out the cause of the thyroid failure later, after the patient is stable. Time is critical—mortality is 25–60% even with treatment.

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