OVERVIEW

What is myxedema coma?

Myxedema coma is a life-threatening condition caused by severe hypothyroidism, characterized by decreased mental status, abnormally low body temperature, and multi-organ dysfunction affecting the cardiovascular, pulmonary, and other systems.

Is myxedema coma common?

Extremely rare.

SYMPTOMS

What are the common manifestations of myxedema coma?

The common manifestations of this condition include the following 6 aspects:

• Neurological abnormalities, such as lethargy, confusion, seizures, hallucinations, delusions, or even coma;

• Electrolyte imbalances, such as decreased sodium levels in the blood;

• Hypothermia, with body temperature possibly dropping below 35°C;

• Difficulty breathing;

• Hypoglycemia;

• Cardiovascular abnormalities, such as slowed heart rate, hypotension or even shock, pericardial effusion, or heart failure;

• Gastrointestinal symptoms, such as bloating and constipation.

How dangerous is myxedema coma?

This condition can lead to organ failure in critical organs such as the heart, lungs, and brain, and may also trigger electrolyte imbalances. The mortality rate can be as high as 30%–40%.

CAUSES

What are the common causes of myxedema coma?

The primary cause of this condition is long-term, severe, and untreated hypothyroidism.

Additionally, certain external factors may trigger the onset of this disease in hypothyroid patients, such as infections, myocardial infarction, exposure to cold, trauma, surgery, or certain medications (sedatives, amiodarone, etc.).

Who is more susceptible to myxedema coma?

Older women are more prone to developing this condition.

DIAGNOSIS

What tests are needed when myxedema coma is suspected?

Thyroid function tests, thyroid autoantibodies, complete blood count, blood glucose, blood electrolytes, blood cortisol and adrenocorticotropic hormone, blood gas analysis, electrocardiogram, thyroid ultrasound, cardiac ultrasound, cranial CT or MRI.

Why are these tests performed for patients with myxedema coma? What is their purpose?

• Thyroid function tests: Used to diagnose hypothyroidism and assess its severity.

• Thyroid autoantibodies: Helps determine the cause and identify autoimmune thyroiditis.

• Complete blood count: Evaluates whether infection is a contributing factor.

• Blood glucose: Determines if hypoglycemia is present.

• Blood electrolytes: Assesses electrolyte imbalances such as hyponatremia.

• Blood cortisol and adrenocorticotropic hormone: Hypothyroidism patients may have adrenal insufficiency; this test checks for adrenal dysfunction.

• Blood gas analysis: Identifies respiratory failure and acid-base imbalances.

• Electrocardiogram: Helps diagnose coexisting heart conditions.

• Thyroid ultrasound: Evaluates thyroid size, morphology, blood flow, nodules, and parenchymal echogenicity to identify the cause of hypothyroidism.

• Cardiac ultrasound: Assesses heart size, structure, function, and pericardial effusion to diagnose cardiac disorders.

• Cranial CT or MRI: Coma has many possible causes; these tests rule out neurological conditions causing impaired consciousness.

What diseases can myxedema coma be easily confused with?

This condition is often mistaken for adrenal insufficiency, anterior pituitary hypofunction, acute cerebral infarction or hemorrhage, and hypoglycemic coma. The above tests help doctors differentiate between these conditions.

TREATMENT

Which department should I visit for myxedema coma?

Due to the severity of the condition, patients often initially seek treatment in the emergency department or ICU. Follow-up care can be provided by endocrinologists or general physicians.

How is myxedema coma treated?

• Hormone replacement: Intravenous levothyroxine, liothyronine, and glucocorticoids are typically administered first until the condition improves and stabilizes, followed by oral levothyroxine.

• Supportive care: Includes fluid replacement, correction of hyponatremia and hypothermia, and mechanical ventilation if needed.

• Addressing triggers: For example, treating infections that may have induced the condition.

How should patients with myxedema coma be cared for?

• Comatose patients should be repositioned with nursing assistance to prevent aspiration of phlegm or nasal secretions.

• Diet should be light and easy to digest.

• Keep warm using blankets or slightly raising room temperature. Avoid hot water bottles or electric blankets, as excessive heat may dilate peripheral blood vessels, increase oxygen consumption, and risk circulatory failure or death.

Do myxedema coma patients require long-term medication?

Yes.

Patients often have severe, permanent hypothyroidism and require lifelong levothyroxine therapy. Discontinuation may trigger a recurrence of myxedema coma.

What should be noted when taking oral levothyroxine for myxedema coma?

Levothyroxine is taken once daily, preferably on an empty stomach in the morning, 0.5–1 hour before breakfast, as some foods may interfere with absorption.

If morning dosing is impractical, it can be taken at bedtime, at least 4 hours after dinner.

Other medications should be taken at least 4 hours apart, as some (e.g., aluminum hydroxide, calcium carbonate, cholestyramine, sucralfate, ferrous sulfate, fiber supplements) may affect absorption or metabolism.

Certain drugs (e.g., phenobarbital, phenytoin, carbamazepine, rifampin, isoniazid, lovastatin, amiodarone, sertraline, chloroquine) may accelerate levothyroxine clearance, necessitating dose adjustments.

Always inform your doctor of concurrent medications to determine proper dosing and timing.

Is follow-up required after discharge for myxedema coma?

Yes. During hospitalization, thyroid function, electrolytes, cortisol, and blood counts are monitored, with medication adjustments as needed.

After discharge, thyroid function should be checked every 4–6 weeks until treatment goals are met.

Once stabilized, monitor thyroid function every 4–6 months. Patients with adrenal insufficiency require biannual checks for cortisol, electrolytes, and blood pressure.

Can myxedema coma be cured?

With prompt treatment, myxedema coma can be resolved, but the underlying hypothyroidism is usually permanent, requiring lifelong levothyroxine.

Recurrence is possible if triggering factors reappear.

DIET & LIFESTYLE

What should patients who have experienced myxedema coma pay attention to in their daily lives?

Take medication on time and attend follow-up examinations; do not stop or reduce dosage without medical guidance.

Most myxedema coma patients are elderly, who may forget medications and experience declining self-care abilities.

Family members should provide close monitoring. Seek immediate medical attention if symptoms like severe cold intolerance, fatigue, drowsiness, edema, constipation, weight gain, or mental confusion/lethargy occur.

PREVENTION

Can Myxedema Coma Be Prevented?

Some patients with myxedema coma may not be aware that they have severe hypothyroidism, especially the elderly. If family members pay more attention to the elderly and promptly seek medical attention when they notice unusual symptoms, some dangerous situations can be avoided.

For patients already diagnosed with hypothyroidism, there are measures to prevent myxedema coma, including:

• Take levothyroxine on time and in the prescribed dosage to treat hypothyroidism, and undergo regular check-ups to maintain thyroid function within the normal range.

• Stay warm in winter and avoid exposure to cold.

• Maintain a balanced diet, exercise regularly, boost immunity, and reduce the risk of infection.

• Avoid self-administering sedatives or sleep medications.

• Actively manage other conditions such as heart disease or hypertension if present.