Myxedema coma, or myxedema crisis, is a complication of advanced hypothyroidism. Hypothyroidism is a condition where the thyroid gland does not produce enough thyroid hormones. Treatment involves thyroid hormone therapy.

This article explores how hypothyroidism causes myxedema coma, before detailing its symptoms, causes, treatment, and diagnosis.

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Myxedema coma is a severe complication of hypothyroidism. The thyroid gland produces hormones, including triiodothyronine (T3) and thyroxine (T4). Hypothyroidism occurs when the thyroid does not produce high enough levels of these hormones.

T3 and T4 regulate several functions in the body, including:

  • body temperature
  • growth
  • heart rate
  • metabolism

If a lack of T3 and T4 severely disrupts these bodily functions, a person may develop symptoms of myxedema coma.

Learn more about normal T4 levels here.

Myxedema coma occurs when the body can no longer tolerate the effects of hypothyroidism.

When thyroid hormone levels become extremely low, a person may experience the following symptoms:

  • confusion or mental slowness
  • hypothermia
  • decreased breathing
  • low blood oxygen levels
  • high blood carbon dioxide levels
  • lower than usual blood sodium levels
  • shock
  • seizures
  • coma

Myxedema coma is a result of untreated or undiagnosed hypothyroidism. However, some contributing factors may trigger myxedema coma sooner in some people.

These include:

  • infection
  • exposure to cold
  • stopping hypothyroid treatment medication
  • stress
  • trauma
  • sudden illness, such as heart attack or stroke

If anyone has hypothyroidism, it is important that they try and keep warm. People should also contact their doctor if an infection, such as a urinary tract infection, takes longer to clear than expected.

A doctor can measure T4 and thyroid-stimulating hormone levels to diagnose myxedema coma.

However, they will likely start with immediate hormone replacement treatment while waiting for the test results based on other symptoms.

These symptoms may include:

  • sparse hair
  • dry skin
  • confusion
  • goiter
  • a possible scar from thyroid surgery
  • hypothermia
  • decreased breathing
  • swelling, especially in the face and legs

A doctor may perform more tests to determine thyroid function and other conditions that could be affecting the thyroid.

If a doctor suspects myxedema coma, they will begin treatment with thyroid hormone therapy, which aims to ease symptoms by restoring T3 and T4 hormone levels.

Depending on how advanced the coma is, doctors will administer T3 and T4 hormones using an intravenous drip. However, a person can receive the treatment orally if they are well enough. In addition to thyroid hormone replacement therapy, people may need other medications such as steroids.

Hypothyroidism occurs when the thyroid gland does not function properly and no longer produces enough thyroid hormones. It may also develop if the pituitary gland does not stimulate it.

Many conditions could lead to hypothyroidism, including:

  • Hashimoto’s thyroiditis: Hashimoto’s thyroiditis is the most common cause of hypothyroidism in the United States.
  • Congenital hypothyroidism: In some cases, the thyroid gland may not function properly from birth, resulting in mental and physical growth issues.
  • Pituitary gland abnormalities: Pituitary tumors or pituitary surgery may affect the function of the gland. When this happens, the pituitary gland is unlikely to produce the right amount of TSH.
  • Sheehan’s syndrome: This involves damage to the pituitary gland and may result in an underactive thyroid.
  • Iodine imbalance (deficiency or excess): If a person does not consume enough iodine, hypothyroidism may occur.

Medication and treatment side effects

Several drugs are known to interfere with thyroid hormone production.

Examples of these drugs include:

  • interferon
  • lithium (Priadel)
  • amiodarone (Pacerone)
  • interleukin-2

People receiving radiation therapy for head and neck cancer may also develop hypothyroidism months or years after treatment.

In addition, thyroid surgery may also lead to hypothyroidism. Treatment for conditions, such as thyroid cancer, thyroid nodules, hyperthyroidism, and goiter, involve partial or full removal of the thyroid gland.

Without treatment, advanced hypothyroidism will likely lead to severe complications, including myxedema coma.

People with myxedema coma generally have positive outcomes if a doctor can quickly administer thyroid hormone therapy. However, without rapid diagnosis and treatment, this condition is often fatal.

Myxedema coma, also known as myxedema crisis, is a severely advanced case of hypothyroidism that constitutes a medical emergency. It is often due to a long history of hypothyroidism going unrecognized or untreated.

Hypothyroidism is a condition where the thyroid gland does not produce enough thyroid hormones to meet the body’s needs.

A myxedema coma diagnosis requires immediate medical attention, which involves treatment with thyroid hormone therapy.