Thyroid storm occurs in people with uncontrolled hyperthyroidism due to a major stress such as:

• Trauma
• Heart attack
• Infection

Rarely, thyroid storm can be caused by radioactive iodine therapy for Graves disease. This can occur even a week or more after treatment.

Symptoms are severe and may include any of the following:

• Agitation
• Change in alertness (consciousness)
• Confusion
• Diarrhea
• Increased temperature
• Pounding heart (tachycardia)
• Restlessness
• Shaking
• Sweating
• Bulging eyeballs

Your health care provider may suspect thyrotoxic storm based on:

• A high systolic (top number) blood pressure reading with a lower diastolic (bottom number) blood pressure reading (wide pulse pressure)
• A very high heart rate
• A history of hyperthyroidism
• An exam of your neck may find that your thyroid gland is enlarged (goiter)

Blood tests are done to check the levels of the thyroid hormones TSH, free T4 and T3.

Other blood tests are done to check heart and kidney functions and to check for infection. Liver function tests provide added diagnosis and treatment information.

Thyroid storm is a medical emergency. It is life threatening. Often, the person needs to be admitted to the intensive care unit. Treatment may include:

• Oxygen therapy for breathing problems
• Fluids for dehydration
• Cooling blankets to return the body temperature to normal
• Monitoring any excess fluid in older people with heart or kidney disease
• Medicines to manage agitation
• Medicine to slow the heart rate
• Vitamins and glucose

The goal of treatment is to decrease thyroid hormone levels in the blood. Sometimes, high doses of iodine is given to try and stun the thyroid. Other medicines known as thionamides may be given to lower the hormone level in the blood. Beta blocker medicines are often given by vein (IV) to slow the heart rate, lower blood pressure, and block the effects of the thyroid hormone excess. In some severe cases, glucocorticoids (steroids) are given.

Antibiotics are given in case of infection.

Irregular heart rhythms (arrhythmias) may occur. Heart failure and fluid in the lungs (pulmonary edema) can develop rapidly and cause death.

This is an emergency condition. Call 911 or the local emergency number if you have hyperthyroidism and experience symptoms of thyroid storm.

To prevent thyroid storm, hyperthyroidism should be treated.

Thyrotoxic storm; Thyrotoxic crisis; Hyperthyroid storm; Accelerated hyperthyroidism; Thyroid crisis; Thyrotoxicosis - thyroid storm

Hollenberg A, Wiersinga WM. Hyperthyroid disorders. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 12.

Pearce EN, Hollenberg AN. Thyroid. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 207.

Thiessen MEW. Thyroid and adrenal disorders. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 117.

Weetman AP, Kahaly GJ. Graves disease. In: Robertson RP, ed. DeGroot's Endocrinology. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 71.

Updated by: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.