What is the treatment for myxedema coma (severe hypothyroidism)?

From the Guidelines

Myxedema coma is a life-threatening emergency requiring immediate hospital admission and a high level of care, including intravenous levothyroxine and supportive therapy. The management of myxedema coma involves a comprehensive approach to address the severe hypothyroidism and associated organ dysfunction. According to the guidelines for managing immune-related adverse events in patients treated with immune checkpoint inhibitor therapy, myxedema coma is a medical emergency that requires admission and a high level of care 1.

Key Management Principles

• Intravenous levothyroxine dosing, as well as steroids, should be considered under the guidance of an inpatient endocrinology consultation 1.
• If there is uncertainty about whether primary or central hypothyroidism is present, hydrocortisone should be given before thyroid hormone is initiated 1.
• Supportive care is crucial and includes managing hypothermia, bradycardia, and altered mental status, which are characteristic of myxedema coma.
• The condition often results from severe hypothyroidism, which may be precipitated by various factors such as infection, medication non-compliance, or cold exposure in patients with underlying thyroid disease.

Treatment Approach

• Intravenous levothyroxine and hydrocortisone are cornerstone treatments, with the exact dosing and administration guided by the clinical context and endocrinology consultation 1.
• Monitoring of thyroid function tests, vital signs, and electrolytes is essential for managing the condition effectively.
• The high mortality rate associated with myxedema coma, particularly in elderly patients or those with multiple comorbidities, underscores the need for prompt and aggressive treatment.

Clinical Considerations

• The development of myxedema coma often represents a failure of outpatient management of hypothyroidism, highlighting the importance of regular monitoring and adherence to thyroid replacement therapy.
• In patients on immune checkpoint inhibitor therapy, regular monitoring of TSH and FT4 levels is recommended to detect hypothyroidism early, potentially preventing the progression to myxedema coma 1.

From the FDA Drug Label

The clinical features of myxedema coma include depression of the cardiovascular, respiratory, gastrointestinal and central nervous systems, impaired diuresis, and hypothermia. Administration of thyroid hormones reverses or attenuates these conditions The therapy of myxedema coma requires simultaneous administration of glucocorticoids. Many investigators recommend that corticosteroids be administered routinely in the initial emergency treatment of all patients with myxedema coma.

The treatment of myxedema coma involves the administration of thyroid hormones, such as liothyronine (T3), and glucocorticoids.

• The goals of treatment are to reverse the depression of various organ systems and to correct hypothermia.
• Liothyronine (T3) is preferred over levothyroxine (T4) because it is more readily available to body tissues and has a more rapid onset of action.
• Glucocorticoids should be administered simultaneously to prevent adrenocortical insufficiency and shock.
• Treatment should be individualized and monitored closely with laboratory tests, including serum T3 and TSH levels 2 2.

From the Research

Definition and Characteristics of Myxedema Coma

• Myxedema coma is a rare endocrine emergency resulting from the decompensation of severe hypothyroidism, associated with a high mortality rate 3.
• It is characterized by the deterioration of mental status, hypothermia, hypotension, hyponatremia, and hypoventilation 3, 4.
• The clinical triad of myxedema coma is altered mental status, hypothermia, and the presence of a precipitating factor 5.

Treatment and Management

• Early disease diagnosis and advancements in intensive supportive care have reduced the mortality rate 3.
• Appropriate management of the underlying thyroid hormone deficiency is essential, and may include a combination of levothyroxine and liothyronine 3, 6.
• Intravenous levothyroxine is often recommended as initial thyroid hormone replacement for myxedema coma, but oral levothyroxine can be an effective option when intravenous therapy is unavailable 7.
• Treatment may also involve addressing precipitating factors such as adrenal insufficiency and hypoglycemia, and providing intensive supportive care 4.

Prognosis and Outcomes

• Mortality associated with myxedema coma is high, approaching 30% with optimized treatment, and nearly 100% if untreated 5.
• Prompt recognition and aggressive management are critical to improving outcomes for patients with myxedema coma 4, 5.
• Long-term management focuses on medication adherence, patient education, thyroid hormone titration, and regular endocrinology follow-up to prevent complications of severe hypothyroidism 4.

Education and Training

• Myxedema coma is a relatively rare presentation to the emergency department, and medical simulation can be an effective method of training emergency medicine residents in its recognition and management 5.
• Simulation-based education can help learners develop a differential diagnosis for a critically ill patient with altered mental status, and initiate life-saving interventions for a patient with decompensated hypothyroidism 5.