Thyroid storm, also known as thyrotoxic crisis, is a life threatening health condition that is associated with untreated or undertreated hyperthyroidism. It can come on suddenly and requires emergency treatment.

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 can be fatal.

If you have hyperthyroidism, you can lower your chances of experiencing thyroid storm by following your doctor’s treatment plan as closely as possible.

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:

Thyroid storm is a rare condition that results from the extreme overproduction of certain hormones.

If you have hyperthyroidism, your thyroid produces too much triiodothyronine (T3) and thyroxine (T4). These hormones control your metabolism, or the rate at which every cell in your body works.

When your thyroid overproduces these hormones, your cells work too quickly. For example, your respiration rate and heart rate become higher than they would usually be. You may even speak far more quickly than you usually do.

Risk factors

Not all people with hyperthyroidism develop thyroid storm, but the risk may increase with:

  • severe undertreated hyperthyroidism
  • infection associated with hyperthyroidism

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

  • trauma
  • surgery
  • severe emotional distress
  • stroke
  • diabetic ketoacidosis
  • congestive heart failure
  • pulmonary embolism (blood clot in the lung)

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.

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, aren’t safe 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:

Earlier medical care is associated with improved survival.

You’ll be less likely to experience complications once your thyroid hormone levels are returned to their typical ranges. Many people experience improvement within 24 hours of treatment.

The most effective way to prevent thyroid storm is to follow your doctor’s hyperthyroidism management plan as closely as possible.

Be sure to take your medications as instructed. Keeping all appointments with your doctor and following through with blood work orders can help your care team 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.

If you have hyperthyroidism, it can also be helpful to tell people who are close to you about the possiblity of experiencing thyroid storm. If they know what symptoms to watch for, they can be better prepared to get you emergency medical care as quickly as possible.

Other steps you can take

Hyperthyroidism requires medical treatments to manage it, but there are some lifestyle changes you could consider making to support your treatment plan.

For example, eating a nutrient-dense diet may help balance your thyroid hormone production. Regular light to moderate physical activity, with the guidance of your doctor, can also benefit your overall health.

Thyroid storm is a life threatening complication of hyperthyroidism that 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.

Talk with your care team about lowering your chances of thyroid storm.