From the Guidelines
Thyroid storm is a life-threatening medical emergency that requires immediate treatment with a multi-faceted approach, including beta-blockers, thionamides, iodine solutions, and corticosteroids, as well as supportive care and continuous cardiac monitoring. The clinical picture of thyroid storm is characterized by extreme manifestations of thyrotoxicosis, including high fever, tachycardia out of proportion to fever, altered mental status, and gastrointestinal symptoms 1. Patients may also present with tremors, sweating, heart failure, and in severe cases, hypotension and shock.
Diagnosis and Treatment
The diagnosis of thyroid storm is based on a combination of signs and symptoms, including fever, tachycardia, altered mental status, vomiting, diarrhea, and cardiac arrhythmia 1. Serum-free triiodothyronine (FT3), FT4, and TSH levels can help confirm the diagnosis, but treatment should not be delayed for test results. The treatment of thyroid storm involves a standard series of drugs, including propylthiouracil or methimazole, saturated solution of potassium iodide or sodium iodide, dexamethasone, and phenobarbital 1. Beta-blockers, such as propranolol, are also widely used to treat the increased heart rate and tremor associated with thyrotoxicosis 1.
Management and Supportive Care
Supportive care is crucial in the management of thyroid storm, including aggressive cooling measures, intravenous fluids, nutritional support, and treatment of the precipitating cause 1. Continuous cardiac monitoring and ICU-level care are essential, as mortality rates can reach 10-30% even with appropriate treatment. The perceived underlying cause of thyroid storm should be treated, and fetal status should be evaluated with ultrasound examination, nonstress testing, or a biophysical profile in pregnant women 1. Unless deemed necessary, delivery during thyroid storm should be avoided.
Key Considerations
- Immediate treatment with a multi-faceted approach is essential to reduce morbidity and mortality.
- Beta-blockers, such as propranolol, are widely used to treat the increased heart rate and tremor associated with thyrotoxicosis 1.
- Supportive care, including aggressive cooling measures, intravenous fluids, and nutritional support, is crucial in the management of thyroid storm.
- Continuous cardiac monitoring and ICU-level care are essential to reduce mortality rates.
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. Beta-adrenergic blockade may mask certain clinical signs of hyperthyroidism. Therefore, abrupt withdrawal of propranolol may be followed by an exacerbation of symptoms of hyperthyroidism, including thyroid storm.
The clinical picture of thyroid storm is not directly described in the provided drug labels. However, thyroid storm is mentioned as a potential condition that can be treated with propylthiouracil and as a potential risk if propranolol is abruptly withdrawn in patients with hyperthyroidism. To treat thyroid storm, propylthiouracil may be an effective treatment by inhibiting the conversion of thyroxine to triiodothyronine in peripheral tissues 2. Propranolol may be used to manage symptoms of hyperthyroidism, but its abrupt withdrawal can exacerbate symptoms, including thyroid storm 3.
From the Research
Clinical Picture of Thyroid Storm
- Thyroid storm is a severe manifestation of thyrotoxicosis, diagnosed by a combination of thyroid function studies showing low to undetectable thyroid stimulating hormone (TSH) (<0.01mU/L) with elevated free thyroxine (T4) and/or triiodothyronine (T3), positive thyroid receptor antibody (TRab) (if Graves' disease is the underlying etiology), and with clinical signs and symptoms of end organ damage 4
- Clinical signs and symptoms of thyroid storm include end organ damage, such as excessive bleeding from highly vascular hyperthyroid tissue or exacerbation of thyrotoxicosis 4
Treatment of Thyroid Storm
- Treatment involves bridging to a euthyroid state prior to total thyroidectomy or radioactive iodine ablation to limit surgical complications 4
- The treatment regimen may incorporate:
- Propranolol to inhibit the catecholamine-mediated peripheral effects of the circulating thyronines 5
- Propylthiouracil to inhibit thyroid hormone synthesis and to inhibit peripheral conversion of thyroxine to triiodothyronine (T3) 5, 6, 7
- Iodine to block the glandular release of thyroid hormones 5, 6
- Dexamethasone along with general supportive therapy 5, 6
- Rectal administration of iodide and propylthiouracil is an effective, readily available, and less expensive alternative to parenteral sodium iodide for patients in thyroid storm with upper gastrointestinal tract dysfunction 6
- Comparison of propylthiouracil vs methimazole for thyroid storm in critically ill patients showed no significant differences in mortality or adverse events between the two treatment groups 7