From the Guidelines
Beta blockers are essential in treating thyroid storm symptoms by controlling the hyperadrenergic manifestations, with propranolol being the preferred agent, as stated in the most recent and highest quality study 1. The symptoms of thyroid storm include fever, tachycardia, altered mental status, vomiting, diarrhea, and cardiac arrhythmia.
- The diagnosis is based on a combination of signs and symptoms, and treatment should not be delayed for test results, as indicated in 2.
- Beta blockers work by blocking the peripheral effects of excess thyroid hormone, reducing heart rate, controlling arrhythmias, and decreasing tremor, anxiety, and heat intolerance.
- Propranolol is typically given at 60-80 mg orally every 4-6 hours or 1-2 mg IV slowly over 10-15 minutes, followed by 2 mg every few hours as needed, as suggested in the example answer.
- For patients with contraindications to propranolol, such as asthma or heart failure, cardioselective beta blockers like metoprolol can be used with caution, as mentioned in 1.
- Beta blockers should be initiated promptly but must be used as part of a comprehensive treatment approach that includes antithyroid drugs, corticosteroids, and cooling measures.
- Vital signs should be monitored closely during treatment, and doses adjusted based on heart rate response, as recommended in 3.
- Beta blockers should be continued until the patient is euthyroid, with gradual tapering to prevent rebound symptoms, as stated in the example answer.
From the FDA Drug Label
Thyrotoxicosis: 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. Metoprolol may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Avoid abrupt withdrawal of beta-blockade, which might precipitate a thyroid storm. Beta-adrenergic blockade may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Abrupt withdrawal of beta blockade might precipitate a thyroid storm; therefore, monitor patients for signs of thyrotoxicosis when withdrawing beta-blocking therapy.
The symptoms of thyroid storm that are masked by beta blockers include tachycardia. Beta blockers, such as propranolol 4, metoprolol 5, and esmolol 6, are used to treat the symptoms of thyroid storm by blocking the effects of excess thyroid hormones on the body.
- Key points: + Beta blockers may mask certain clinical signs of hyperthyroidism + Abrupt withdrawal of beta blockers may precipitate a thyroid storm + Monitor patients for signs of thyrotoxicosis when withdrawing beta-blocking therapy
From the Research
Symptoms of Thyroid Storm
- Increased thyroid hormones and exaggerated symptoms of thyrotoxicosis 7
- Symptoms include altered mental status, heart rate abnormalities, and other systemic symptoms 7, 8
Treatment with Beta Blockers
- Beta blockers, such as propranolol, are used to inhibit the catecholamine-mediated peripheral effects of circulating thyronines 8
- Propranolol is the chosen drug for blockade in hyperthyroidism and thyroid storm due to its additional effect of preventing the peripheral conversion of dormant T4 to active form T3 9
- However, caution is advised when using beta blockers in patients with thyroid storm, especially those with coexisting atrial fibrillation, as they may cause cardiovascular collapse 9, 10
- Esmolol, a short-acting beta blocker, has been reported to cause cardiac arrest in patients with thyroid storm complicated by atrial fibrillation 10