ICD-11 Codes
for 5A00.21 - Myxoedema coma

Teodor Jurukovski January 1, 1970

Fact checked by: Teodor Jurukovski

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Understanding Myxoedema Coma: A Critical Hypothyroid Complication

Myxoedema coma, identified by the ICD-11 code 5A00.21, represents a rare but severe and life-threatening manifestation of hypothyroidism. It occurs when the body's ability to compensate for critically low thyroid hormone levels fails, leading to widespread organ dysfunction and a significant decline in mental status. This condition, sometimes referred to as hypothyroid coma or decompensated hypothyroidism, requires immediate medical intervention.

Factors Contributing to Myxoedema Coma

The primary cause of myxoedema coma is long-standing, severe, and untreated hypothyroidism. However, several factors can precipitate this crisis in individuals with pre-existing thyroid deficiency. These include discontinuing or skipping thyroid hormone medication, exposure to cold temperatures, infections such as pneumonia, surgical procedures, trauma, and the use of certain medications like sedatives, tranquilizers, lithium, or amiodarone. Risk factors also include being female and over the age of 60.

Recognizing the Signs: Symptoms of Myxoedema Coma

Patients experiencing myxoedema coma often present with a progressive deterioration in mental status, which can range from apathy, confusion, and disorientation to profound lethargy or coma. Other critical signs include:

• Hypothermia (low body temperature)
• Bradycardia (slow heart rate)
• Hypotension (low blood pressure)
• Slowed or shallow breathing
• Edema (swelling), particularly in the face and extremities
• Profound fatigue

Diagnosing Myxoedema Coma

The diagnosis of myxoedema coma (ICD-11 code 5A00.21) relies on a combination of clinical presentation, patient history, and laboratory findings. Healthcare providers will assess for symptoms of severe hypothyroidism and potential precipitating factors. Blood tests are crucial to confirm critically low thyroid hormone levels (e.g., reduced FT4 or FT3) and elevated TSH (in primary hypothyroidism). Given the severity, patients are typically admitted to an intensive care unit (ICU) for prompt evaluation and management.

Medical Management of Myxoedema Coma

Management of myxoedema coma is an emergency requiring intensive care. Treatment focuses on stabilizing the patient and restoring thyroid hormone levels. Key interventions include:

• Intravenous administration of thyroid hormones, such as levothyroxine (T4) and sometimes liothyronine (T3).
• Intravenous fluids to maintain blood pressure and correct electrolyte imbalances.
• Supportive care, including oxygen therapy or mechanical ventilation if breathing is compromised.
• Hydrocortisone therapy to address potential adrenal insufficiency.
• Prompt treatment of any underlying precipitating causes, such as infections.

ICD-11 Coding for Myxoedema Coma

For accurate medical billing and record-keeping, the ICD-11 code for myxoedema coma is 5A00.21. This code is used to report this specific, severe form of hypothyroidism. Common clinical synonyms include hypothyroid coma and myxoedematous coma. Proper documentation of the patient's condition, symptoms, and treatment is essential for correct coding and reimbursement. This condition is reportable and billable.