Thyroid storm causes an increased heart rate, blood pressure, and body temperature. It may occur in people with hyperthyroidism. It can be life threatening without treatment.

Thyroid storm, also known as thyrotoxic crisis, is a life threatening health condition that is associated with untreated or undertreated hyperthyroidism.

During thyroid storm, an individual’s heart rate, blood pressure, and body temperature can increase to very high levels. Without prompt, aggressive treatment, thyroid storm is often fatal.

Keep reading to learn the causes and symptoms of thyroid storm and how to treat and prevent it.

Thyroid storm is rare. It develops in people who have hyperthyroidism, including Graves’ disease, but aren’t receiving appropriate treatment.

If you have hyperthyroidism, your thyroid produces too much triiodothyronine (T3) and thyroxine (T4). These hormones control the rate at which every cell in your body works (metabolism). This causes all of your cells to work too quickly. For example, your respiration rate and heart rate become higher than they normally would be. You may even speak far more quickly than you usually do.

Thyoid storm results from the extreme overproduction of these two hormones. Not all people with hyperthyroidism develop thyroid storm. Causes of thyroid storm include:

  • severe undertreated hyperthyroidism
  • infection associated with hyperthyroidism

People with hyperthyroidism may develop thyroid storm after experiencing one of the following:

Learn about the causes of hyperthyroidism.

Symptoms of thyroid storm are similar to those of hyperthyroidism, but they are more sudden, severe, and extreme. People with thyroid storm may not be able to seek care on their own. Common symptoms include:

Individuals with hyperthyroidism who experience any symptoms of thyroid storm are typically admitted to the hospital. If you suspect you or someone else has thyroid storm symptoms, call 911 immediately.

A medical professional will likely begin supportive care while testing for indicators of thyroid storm. This can include:

  • taking your blood pressure, as people with thyroid storm tend to have an elevated systolic blood pressure (the top blood pressure number)
  • measuring your heart rate, which is elevated in people with thyroid storm
  • measuring your thyroid hormone levels with a blood test

Thyroid-stimulating hormone (TSH) levels tend to be low in hyperthyroidism and thyroid storm. Normal levels fall between 0.4 to 4.5 milliunits per liter (mU/L).

T3 and T4 hormones are elevated in people with thyroid storm.

Thyroid storm develops abruptly and affects all the systems of your body.

Treatment begins as soon as thyroid storm is suspected, usually before lab results are ready. This includes an antithyroid medication to reduce the production of T3 and T4. Medications include:

  • propylthiouracil (also called PTU)
  • methimazole (Tapazole)

Medical professionals may also administer:

Some of these treatments, including propranolol, may not be used for people who are pregnant.

Treating hyperthyroidism

Hyperthyroidism requires ongoing care. People with hyperthyroidism may be treated with radioactive iodine, which destroys the thyroid, or a course of drugs to suppress thyroid function temporarily.

Pregnant people who have hyperthyroidism can’t be treated with radioactive iodine as it can negatively affect the pregnancy and fetus. In pregnant people, doctors may remove the thyroid surgically.

People experiencing thyroid storm should avoid taking iodine instead of medical treatment, as this can worsen the condition.

If your thyroid is destroyed by radioactive iodine treatment or removed surgically, you will need to take synthetic thyroid hormone for the rest of your life.

Thyroid storm requires immediate, aggressive emergency medical attention. Untreated, thyroid storm can cause:

  • congestive heart failure
  • pleural effusion, or fluid-filled lungs
  • arrhythmias
  • multiple organ failure
  • death

If you quickly seek medical care, your chances of surviving thyroid storm increase. Earlier medical care is also associated with improved survival.

Related complications may be lessened once your thyroid hormone levels are returned to the normal range (known as euthyroid).

Many people experience improvement within 24 hours of treatment.

The most effective way to prevent the onset of thyroid storm is to keep up with your thyroid health plan.

Be sure to take your medications as instructed. Keeping all appointments with your doctor and following through with blood work orders can help healthcare professionals track and manage your T3 and T4 levels.

If you experience new or worsening symptoms of hyperthyroidism, which may be different in males and females, it’s best to talk with your doctor.

Thyroid storm is a life threatening complication of hyperthyroidism. It requires emergency care.

Typical symptoms include a racing heart and high systolic blood pressure.

Getting treatment sooner is associated with an improved chance of survival, but untreated, thyroid storm can be fatal.