Thyroid Storm

Thyroid storm is acute, life-threatening decompensation caused by excessive thyroid hormone action. It is not diagnosed by an impressive thyroid hormone result alone. The danger appears when the hypermetabolic state overwhelms cardiovascular, neurological, thermoregulatory, gastrointestinal, and hepatic function. A typical pattern is high fever, marked tachycardia, diaphoresis, tremor, agitation or delirium, vomiting or diarrhoea, and signs of heart failure. Atrial fibrillation may develop. The patient can move from a high-output state to reduced cardiac output, hypotension, pulmonary oedema, and shock as the heart exhausts its reserve. Thyroid hormone increases oxygen consumption and heat production. It also increases tissue responsiveness to catecholamines, so an otherwise tolerable stressor can produce extreme tachycardia, vasodilation, agitation, and myocardial oxygen demand. Older adults may present less dramatically, with weakness, confusion, or worsening heart failure rather than a striking fever. The experienced nurse recognizes the combination: a patient with known or suspected hyperthyroidism who is hot, fast, neurologically changed, and systemically unwell. One abnormal vital sign does not establish storm, but the cluster demands emergency assessment.