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Thyroid storm is a life-threatening condition that develops in cases of untreated thyrotoxicosis (hyperthyroidism, or overactive thyroid).

Thyrotoxic storm; Hyperthyroid storm; Accelerated hyperthyroidism

Thyroid storm results from untreated hyperthyroidism. It is usually brought on by a stress such as trauma or infection.

Symptoms are severe and may include:

• Agitation
• Change in alertness (consciousness)
• Confusion
• Diarrhea
• Fever
• Pounding heart (tachycardia)
• Restlessness
• Shaking
• Sweating

• The top number in a blood pressure reading may be high
• Heart rate is increased

Blood tests are done to evaluate thyroid function.

• TSH is usually too low to detect.
• Thyroid hormone levels such as free T4 and total T3 are high.

Congestive heart failure and pulmonary edema can develop rapidly and lead to death.

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

AACE Thyroid Task Force. American Association of Clinical Endocrinologists medical guidelines for clinical practice for the evaluation and treatment of hyperthyroidism and hypothyroidism. Endocr Pract. 2002;8(6):457-469.

Ladenson P, Kim M. Thyroid. In: Goldman L and Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders; 2007:chap 244.

Davies TF, Larsen PR. Thyrotoxicosis. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. Philadelphia, Pa: Saunders Elsevier;2008:chap 11.