What are the symptoms of thyroid storm (thyrotoxic crisis)?

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Last updated: March 25, 2025View editorial policy

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From the Guidelines

Thyroid storm is a life-threatening medical emergency characterized by extreme symptoms of hyperthyroidism, including high fever, rapid heart rate, agitation, confusion, and seizures, which can lead to heart failure, coma, and death if not promptly treated. The main symptoms of thyroid storm include fever; tachycardia out of proportion to the fever; altered mental status (nervousness, restlessness, confusion, seizures), vomiting, diarrhea, and cardiac arrhythmia, as noted in the study by 1. Patients may also experience severe nausea, vomiting, diarrhea, abdominal pain, and profound weakness, as well as tremors, restlessness, and extreme anxiety. Some patients develop congestive heart failure with shortness of breath and swelling in the legs, and jaundice may occur due to liver dysfunction.

The symptoms of thyroid storm can be summarized as follows:

  • High fever (often above 102°F/38.9°C)
  • Rapid heart rate (tachycardia) exceeding 140 beats per minute
  • High blood pressure
  • Irregular heartbeat
  • Extreme agitation, confusion, delirium, psychosis, seizures, and even coma
  • Severe nausea, vomiting, diarrhea, abdominal pain, and profound weakness
  • Tremors, restlessness, and extreme anxiety
  • Congestive heart failure with shortness of breath and swelling in the legs
  • Jaundice due to liver dysfunction

According to the most recent study by 1, beta-blockers, such as propranolol, can be used to control heart rate and tremors in patients with thyrotoxicosis or symptomatic hyperthyroidism. However, the primary study guiding the diagnosis and treatment of thyroid storm remains the 2002 study by 1, which emphasizes the importance of prompt treatment with medications to block thyroid hormone production, beta-blockers, corticosteroids, and supportive care. Without prompt treatment, thyroid storm can lead to heart failure, coma, and death, with mortality rates of 10-30% even with treatment.

From the Research

Symptoms of Thyroid Storm

The symptoms of thyroid storm, also known as thyrotoxic crisis, include:

  • Fever 2, 3
  • Tachycardia 2, 3, 4, 5
  • Signs of congestive heart failure 2
  • Vomiting/diarrhea 2
  • Hepatic dysfunction 2
  • Central nervous system disturbance 2, 3, 5
  • Hyperthermia 3, 4, 5
  • Altered mental state with severe agitation 3
  • Myasthenia 5
  • Cardiovascular symptoms 5

Clinical Features and Diagnosis

Thyroid storm is characterized by exaggerated signs and symptoms of thyrotoxicosis and evidence of multiorgan decompensation, usually occurring in the presence of an inciting trigger 2. The diagnosis is made based on clinical criteria, such as the Burch-Wartofsky point scale and Japan Thyroid Association diagnostic criteria 2, as thyroid hormone measurements do not differentiate between thyroid storm and uncomplicated hyperthyroidism 3, 5.

Precipitating Factors

Thyroid storm can be precipitated by various factors, including:

  • Infection 3, 5
  • Iodine contamination 3
  • Surgery 3, 5
  • I-131 treatment 3
  • Trauma 5

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

High risk and low prevalence diseases: Thyroid storm.

The American journal of emergency medicine, 2023

Research

Thyroid emergencies.

Bailliere's clinical endocrinology and metabolism, 1992

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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