ICD-10 Code E03.5 – Myxedema coma (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E03.5 – Myxedema coma
What it is
Myxedema coma is a severe, life-threatening form of hypothyroidism. It reflects profound thyroid hormone deficiency with marked slowing of body functions.
Clinical signs
Typical features include altered mental status, hypothermia, bradycardia, and respiratory depression. Clinical features vary; refer to documentation.
When to use this code
Use E03.5 when the record documents myxedema coma, myxedema crisis, or decompensated severe hypothyroidism with coma or near-coma. You should code it only when the provider clearly links the presentation to thyroid failure.
Do not use for
Do not use this code for uncomplicated hypothyroidism, thyroiditis, or nonspecific lethargy without coma-level decompensation. Check documentation if the diagnosis is uncertain.
Coding tip
Confirm that the provider explicitly documents myxedema coma or equivalent wording before assigning E03.5.