Myxedema refers to a severe form of hypothyroidism than can occur when the condition is left untreated or is not treated sufficiently. The term also applies to the effects that hypothyroidism can have on the skin, making it appear swollen and puffy.

When thyroid hormone levels become extremely low, a person may experience symptoms such as drowsiness, confusion, hypothermia, and changes to the skin. Research on animals suggests that thyroid hormones help regulate many key skin processes, so thyroid disorders could affect skin healing and health.

Myxedema in the context of the skin means that the skin swells and gains a waxy consistency.

One life threatening complication of hypothyroidism is myxedema coma. This complication is also known as myxedema crisis, which is a more accurate term, as a person experiencing myxedema coma is not actually in a coma.

The mortality rate for myxedema crisis is between 20–60%, even with treatment. Keep reading to learn more about myxedema, including the causes, symptoms, and treatment methods.

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Myxedema occurs because of severe poorly managed or untreated hypothyroidism. A person may develop this complication if they do not seek care, stop taking their medication, or take the wrong dose of medication.

Hypothyroidism develops because the thyroid stops working as it should. Causes of hypothyroidism include:

  • surgical removal of the thyroid
  • medications that affect the hormone system, such as some for cancer treatment
  • radiation therapy to treat cancer
  • other medications, including lithium, beta-blockers, and anesthesia
  • autoimmune conditions, such as Hashimoto’s thyroiditis
  • iodine deficiency or an excess of iodine
  • pregnancy
  • sudden illness or infection

Myxedema may refer to two separate conditions: the skin consequences of hypothyroidism (especially poorly controlled hypothyroidism) or a severe hypothyroid crisis.

Skin myxedema

Myxedema of the skin can occur in people with both hypothyroidism and hyperthyroidism, including those with Grave’s disease.

A person may have symptoms of thyroid dysfunction, such as trouble regulating their body temperature, unexplained weight loss or gain, dry skin, or an irregular heart rate before symptoms develop. Symptoms of skin myxedema include:

  • skin that looks swollen
  • skin that has a waxy appearance
  • lesions on the skin
  • pits in the skin when a person presses their skin
  • an orange peel-like appearance to the skin

It most commonly affects the lower legs. This is pretibial myxedema.

Myxedema coma

Myxedema coma is a serious condition. Any person displaying symptoms of myxedema or severe hypothyroidism must seek emergency medical attention.

Myxedema coma is not actually a coma. However, it can cause trouble thinking clearly and altered states of consciousness. Without treatment, a person may fall into a coma. Some symptoms include:

A person experiencing a myxedema crisis will not have just one or two symptoms. They will feel very sick and get progressively worse.

Other symptoms of severe hypothyroidism can include:

People should also note that a myxedema coma can occur in patients who forget to take their thyroid hormone replacement, such as older adults with dementia or patients in general who do not take medication as prescribed.

A synthetic version of the T4 thyroxine hormone called levothyroxine can treat hypothyroidism. This restores T4 hormone levels and can help relieve associated symptoms.

People with myxedema coma need admission to an intensive care unit, where they can get continual monitoring and treatment. Mortality rates are high — as high as 60% in some cases — and recovery can take weeks.

Treatment involves administering thyroid hormone replacement medication into a vein. Antibiotics, steroid treatment, and breathing support may help with symptoms.

Treatment focuses on managing symptoms. For example, a person may need warming blankets to help them maintain a healthy body temperature.

A person may need breathing assistance, such as continuous positive airway pressure (CPAP), if carbon dioxide levels in the blood are very high. Doctors will also monitor heart rhythms and blood pressure carefully.

A person who recovers from myxedema will need to continue to take medication, probably for the rest of their life.

A doctor will make a diagnosis after seeing if a person’s symptoms are consistent with severe hypothyroidism. They may also perform a blood test to measure thyroid hormone levels.

A person with a high level of thyroid-stimulating hormone (TSH) may have hypothyroidism, as the body may produce extra TSH to make up for the underactive thyroid. As a result, a doctor may measure how much TSH a person’s pituitary gland produces.

A thyroxine or T4 test can measure a person’s T4 level. Low levels of T4 are a good indicator of hypothyroidism, especially if combined with high levels of TSH.

If a doctor believes that a person has hypothyroidism, they will perform more tests to measure thyroid function and to find an underlying cause.

Testing for myxedema coma involves looking for signs of organ damage and heart dysfunction, and ruling out other causes. A doctor may recommend an electrocardiogram, blood tests to look for signs of infection and kidney problems, and imaging scans of the heart and other organs.

If a doctor suspects myxedema coma, they will recommend immediate emergency treatment. The sooner a person is treated, the more likely they are to recover.

Complications of myxedema include:

Myxedema coma is a rare but severe complication of hypothyroidism. It is a life threatening complication with a mortality rate of 25–60 percent. Females are more vulnerable, especially during the winter months.

People with skin myxedema may have poorly controlled thyroid disease. This increases their risk of thyroid complications, including myxedema coma.

The sooner a person with advanced hypothyroidism receives treatment, the less likely they are to develop dangerous complications. Even with treatment, the mortality rate for a person with myxedema coma is high.

A person has a much higher chance of recovery with early recognition and treatment.

A person will usually need lifelong treatment to maintain normal thyroid levels after they recover. However, if the condition is well-controlled, it will not affect the person’s life expectancy.

Myxedema and myxedema coma are both complications of uncontrolled thyroid disease.

A person who notices skin changes should see a doctor, especially if they have a history of thyroid disease. Treating the condition that caused the skin changes may help prevent serious complications.

The thyroid helps control many important functions, including heart rhythms, metabolism, and body temperature. When it does not work well, a person can experience serious complications.

Myxedema coma is a medical crisis that warrants immediate treatment. Controlling hypothyroidism can help prevent it.

People with thyroid disease or symptoms of thyroid disease should see a doctor and ask for thyroid testing. Early intervention can prevent serious complications, including the life threatening complications myxedema coma can cause.