From the Guidelines
Thyroid storm is a life-threatening medical emergency that requires immediate treatment with a combination of propylthiouracil or methimazole, saturated solution of potassium iodide or sodium iodide, and dexamethasone, along with general supportive measures. 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, as outlined in the American College of Obstetricians and Gynecologists (ACOG) practice bulletin on thyroid disease in pregnancy 1.
Treatment Approach
The treatment approach involves a multi-targeted strategy to control the extreme hypermetabolic state associated with thyroid storm. This includes:
- Administering propylthiouracil or methimazole to block new thyroid hormone synthesis
- Giving saturated solution of potassium iodide or sodium iodide to block thyroid hormone release
- Using dexamethasone to reduce T4 to T3 conversion and treat potential adrenal insufficiency
- Providing general supportive measures, such as oxygen, antipyretics, and appropriate monitoring
Supportive Care
Supportive care is crucial in managing thyroid storm, including:
- Aggressive cooling to control fever
- IV fluids to maintain hydration
- Glucose supplementation to prevent hypoglycemia
- Treating the precipitating cause, such as infection, trauma, or surgery
Fetal Evaluation
Depending on gestational age, fetal status should be evaluated with ultrasound examination, nonstress testing, or a biophysical profile, as recommended by the ACOG practice bulletin 1. Unless deemed necessary, delivery during thyroid storm should be avoided to minimize risks to both the mother and the fetus.
Mortality and Morbidity
Without prompt treatment, mortality rates for thyroid storm can be high, reaching 10-30%, emphasizing the importance of rapid recognition and aggressive management 1. The goal of treatment is to reduce morbidity and mortality by controlling the extreme hypermetabolic state and preventing complications such as maternal heart failure, shock, stupor, and coma.
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.
Propylthiouracil may be an effective treatment for thyroid storm because it inhibits the conversion of thyroxine to triiodothyronine in peripheral tissues 2.
- It is used in the treatment of hyperthyroidism.
- The drug does not provide a direct answer regarding the use of methimazole for thyroid storm.
From the Research
Definition and Treatment of Thyroid Storm
- Thyroid storm is a potentially lethal complication of hyperthyroidism with increased thyroid hormones and exaggerated symptoms of thyrotoxicosis 3.
- The treatment regimen for thyroid storm incorporates several components, including:
- Propranolol to inhibit the catecholamine-mediated peripheral effects of the circulating thyronines 4.
- Propylthiouracil or methimazole to inhibit thyroid hormone synthesis and to inhibit peripheral conversion of thyroxine to triiodothyronine (T3) 4, 5.
- Iodine to block the glandular release of thyroid hormones 4.
- Dexamethasone along with general supportive therapy 4.
- Therapeutic plasma exchange (TPE) for patients who fail medical therapy or are not suitable for thyroidectomy 3, 6.
Comparison of Treatment Options
- A comparative effectiveness study found no significant differences in mortality or adverse events between patients treated with propylthiouracil and those treated with methimazole for thyroid storm 5.
- The study suggests that current guidelines recommending propylthiouracil over methimazole for treatment of thyroid storm may merit reevaluation 5.
- Another study reported a case of thyroid storm that was promptly reversed by aggressive medical therapy with antithyroid agents and steroid pulse, highlighting the beneficial impact of early diagnosis and intensive therapy 7.
Therapeutic Plasma Exchange
- TPE is a safe and effective treatment for thyroid storm when conventional treatments are not successful or appropriate 3.
- TPE can remove T3 and T4 bound to albumin, autoantibodies, catecholamines, and cytokines, and is likely beneficial for patients with thyroid storm 3.
- A case report described a patient with thyroid storm who underwent TPE daily for 4 days, resulting in normalized thyroid hormones and resolution of symptoms 3.