What is a thyroid storm (thyrotoxic crisis)?

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Last updated: March 18, 2025View editorial policy

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From the Guidelines

Thyroid storm is a life-threatening medical emergency characterized by an extreme hypermetabolic state, requiring immediate treatment with a combination of medications and supportive care to prevent high mortality rates. It is associated with a high risk of maternal heart failure, particularly in pregnant women, and is diagnosed based on a combination of signs and symptoms, including fever, tachycardia, altered mental status, vomiting, diarrhea, and cardiac arrhythmia 1. The diagnosis is confirmed by serum-free triiodothyronine (FT3), FT4, and TSH levels, but treatment should not be delayed for test results.

Key Characteristics of Thyroid Storm

  • High fever
  • Tachycardia out of proportion to the fever
  • Altered mental status (nervousness, restlessness, confusion, seizures)
  • Vomiting, diarrhea, and cardiac arrhythmia
  • An inciting event, such as surgery, infection, labor, or delivery, may be identified

Treatment Approach

The treatment of thyroid storm involves a standard series of drugs, including:

  • Propylthiouracil or methimazole to block hormone production
  • Saturated solution of potassium iodide or sodium iodide to block hormone release
  • Dexamethasone to reduce conversion of T4 to T3
  • Phenobarbital for supportive care General supportive measures, such as oxygen, antipyretics, and appropriate monitoring, are also crucial in managing thyroid storm 1.

Important Considerations

  • Fetal status should be evaluated with ultrasound examination, nonstress testing, or a biophysical profile, depending on gestational age
  • Delivery during thyroid storm should be avoided unless deemed necessary
  • The perceived underlying cause of thyroid storm should be treated promptly to prevent further complications.

From the FDA Drug Label

Propylthiouracil inhibits the conversion of thyroxine to triiodothyronine in peripheral tissues and may therefore be an effective treatment for thyroid storm.

A thyroid storm (thyrotoxic crisis) is not directly defined in the provided text, but it is mentioned as a condition for which propylthiouracil may be an effective treatment.

  • The text does not provide a clear definition of thyroid storm.
  • It only implies that thyroid storm is a condition related to hyperthyroidism that may require treatment with propylthiouracil 2.

From the Research

Definition and Overview

  • Thyroid storm, also known as thyrotoxic crisis, is a life-threatening complication of hyperthyroidism that requires early diagnosis and aggressive treatment 3, 4, 5, 6, 7.
  • It is a rare but potentially life-threatening medical emergency that can occur in patients with hyperthyroidism, particularly in those with a history of Graves' disease or other thyroid disorders 3, 6.

Clinical Presentation

  • The clinical presentation of thyroid storm can vary, but common symptoms include tremors, atrial fibrillation, dyspnea, leg swelling, and encephalopathy 3, 5.
  • In some cases, thyroid storm can present with cardiac arrest and subsequent multiorgan failure, as seen in a case report of a 22-year-old female patient with a history of Graves' disease 6.
  • Acute airway obstruction can also occur in patients with thyroid storm, particularly in those with a large thyroid gland, and requires urgent attention 5.

Diagnosis and Treatment

  • The diagnosis of thyroid storm is made entirely on clinical findings, and any delay in therapy can be fatal 7.
  • Medical treatment is based on three principles: counteracting the peripheral effects of thyroid hormones, inhibiting thyroid hormone synthesis, and treating systemic complications 7.
  • Treatment options include beta-blockers, antithyroid drugs, glucocorticoids, and other medications, as well as plasmapheresis and continuous renal replacement therapy (CRRT) in severe cases 3, 6.
  • Early thyroidectomy should be considered as the treatment of choice if medical treatment fails to result in clinical improvement 7.

Prognosis and Mortality

  • The mortality rate for thyroid storm is significant, ranging from 10-50% in different studies 4, 7.
  • Delayed treatment and failure to recognize the condition can lead to a higher mortality rate, emphasizing the importance of prompt diagnosis and aggressive treatment 7.

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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