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Myxedema Coma and Hypothyroidism

What you should know

With Omayra M. Quijano-Vega MD and Leanna Poston MD

Myxedema coma is a rare and potentially fatal complication of hypothyroidism.

While thyroid disorders — and hypothyroidism in particular — can lead to serious health issues, proper management and care can prevent risky health complications from occurring. One of those complications is myxedema coma. 

What is hypothyroidism—and how can it lead to myxedema coma?

Hypothyroidism is a condition in which the thyroid gland — a tiny, butterfly-shaped gland at the bottom of your neck — is unable to make enough thyroid hormone. This powerful gland is not to be overlooked; when it doesn’t make enough hormone, you might be at risk of hypothyroidism.

Symptoms of hypothyroidism

The symptoms, which are frustrating at best and medically urgent at worst, include but are not limited to:

  • extreme fatigue
  • heart issues
  • intolerance to cold
  • mood changes (anxiety, depression)
  • slowed metabolism
  • dry skin
  • constipation
  • increase in LDL, aka ‘bad’ cholesterol
  • joint pain

Even worse than the above symptoms? Myxedema coma, which is an extreme (and thankfully relatively uncommon) complication of hypothyroidism brought on by undiagnosed or under-treated hypothyroidism.


Anyone with hypothyroidism, a history of neck surgery, or radioactive iodine treatment could be at risk for this life-threatening complication. However, there are some higher risk groups, according to Dr. Leanna Poston, such as older women (over the age of 60) who have a history of primary hypothyroidism. 

Symptoms of myxedema coma

There are a few core symptoms of myxedema coma, according to Omayra M. Quijano-Vega, MD, specialist in endocrinology, diabetes, and metabolism at Paloma Health. They include:

Altered mental status: You might experience extreme drowsiness and lethargy for an extended period of time. This can turn into a stupor, and eventually, a sort of coma. The term “coma” is also a misnomer, as most patients are not comatose, per se. Rather, patients are mentally altered in a noticeable way. 

Low temperature: Myxedema leads to a very low temperature. Unfortunately, lower temperatures can lead to more severe myxedema. Patients who have severe, untreated hypothyroidism during winter may risk developing myxedema coma. 

A precipitating health event: Someone who experiences myxedema coma might have had some sort of change in their living situations or habits (including use of drugs or medicine), or recently had an infection, stroke, heart issue, or other health issue. 

Myxedema coma is usually associated with increased thyroid stimulating hormone and decreased free T4 and free T3 levels.

Dr. Quijano-Vega says that the typical myxedema coma patient is usually an older woman with altered consciousness. She might present in the wintertime with low body temperature, low respiration, low blood pressure, low heart rate, rough and dry skin, and delayed tendon reactions. The myxedematous face (the face you may have if you have myxedema coma) is usually puffy with sagging eyelids and swelling around the eyes. This is a symptom you probably can’t miss, especially if you’re feeling exceptionally lethargic, exhausted, or have been sick or off your medication.

Fortunately, Dr. Quijano-Vega says that the condition itself is uncommon. Although when it does occur, it has a mortality rate of about 30 to 60 percent. 

Meet a myxedema coma patient

Ruth, a 63-year-old woman who has lived with hypothyroidism for more than decade, was hospitalized and diagnosed with myxedema coma after not taking her thyroid medication for six weeks. She says she wasn’t aware that myxedema was a risk at all. For this reason, it’s important that you take note of any symptoms you are having, especially if you’ve switched medications or stopped medication.

Ruth said that the week leading up to her hospitalization she experienced “swollen face and eyes, rapid weight gain, trouble thinking, a deep voice, total loss of energy, and cramps and tingling in my arms and legs.” She said that doctors told her that her thyroid hormones T3 and T4 were “nonexistent,” while her thyroid-stimulating hormone levels were increased. “Had I waited, I wouldn’t be here right now,” she said. It took her three months to recover. 

Dr. Quijano-Vega wants to share a message loud and clear for hypothyroid patients all over: “Patients who have been diagnosed with hypothyroidism need to understand that it is important for their thyroid hormone replacement therapy to be taken on a daily basis, as per instructions of their treating doctor.”


According to Dr. Poston, you’ll first need your thyroid-stimulating hormone tested. “TSH stimulates the thyroid gland to produce thyroid hormone. If the thyroid gland is unable to produce thyroid hormone, TSH will continue to be produced in an attempt to prod the thyroid gland into production.”

But what happens if the TSH level is elevated? “The next step is to repeat the test with a serum-free thyroxine measurement. Hypothyroidism will present with a high TSH and a low serum free T4 level.” 

If you want to understand more about your thyroid health and any potential risk for myxedema coma, ask your doctor the following questions:

  • What is the difference between TSH, T3, and T4—and what might cause them to increase or decrease?
  • How long will I need medicine for my hypothyroidism and what are the side effects? What will happen if I change or stop my medication?
  • What hormones levels are the goal for me in order to stay healthy?
  • Am I at risk of myxedema coma?
  • What should I do if I develop myxedema symptoms?
  • When should my thyroid hormone levels be checked and re-checked?
  • What causes an imbalance in my hormone levels if I am taking my medication?
  • How quickly can I balance my hormone levels if they do change?


It’s important that you take the medication prescribed by your doctors, and that you regularly have your thyroid hormones tested. To support a healthy thyroid in general, diet is important, according to Dr. Poston. You’ll want to make sure you get adequate amounts of iodine, which is a mineral your body needs to make thyroid hormone. Reach for fish, dairy foods, iodized salt, and seaweed. You’ll also need tyrosine, which can be found in foods like chicken, lima beans, and almonds. 

You’ll want to avoid eating lots of goitrogens, which can impede thyroid function. Unfortunately, these foods are very popular, and they include spinach, soybeans, strawberries, sweet potatoes, broccoli, and Brussels sprouts, among others. A full list of foods to support thyroid function can be found here. It’s important to note that eating too much dietary fiber (think oatmeal, beans, nuts) can impair the absorption of thyroid hormone replacement medication. 

Dr. Poston says there are other ways to support thyroid health: “Avoid exposure of the thyroid gland to unnecessary medical radiation, including PET scans, CT scans, and X-rays.” If you do have to get an X-ray, make sure you get a throat or thyroid cover. 

While everything you now know about myxedema coma may sound frightening, this condition is rare. You should also know that by taking a daily pill prescribed by your doctor, you can work towards maintaining healthy thyroid hormone levels.



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Complications of Hypothyroidism