E03.5 Myxedema coma

ICD-10-CM E03.5: Myxedema Coma Reference

ICD-10-CM code E03.5 represents myxedema coma, classified as a disease or syndrome under other hypothyroidism. The condition is a severe, life-threatening manifestation of hypothyroidism marked by altered mentation and multiorgan dysfunction. This reference outlines code structure and clinical context without providing personal medical advice. 1 2

Plain-language overview

Myxedema coma is identified as the most severe, life-threatening manifestation of hypothyroidism, characterized by altered mentation and multiorgan dysfunction, and it carries high mortality rates despite advances in intensive care. 2

What this code represents

In the ICD-10-CM terminology, E03.5 is an active code with the preferred name myxedema coma, and its semantic type is classified as a disease or syndrome. 1

The code E03.5 falls under the parent category E03 for other hypothyroidism, and the terminology record explicitly indicates that this specific code has narrower concepts within the hierarchy. 1 4

Coding details

The E03.5 code is situated within chapter four of the ICD-10-CM system, specifically nested under the E00-E07 block of disorders involving the thyroid gland. 4

Clinical context

Effective management of myxedema coma requires a high index of suspicion, rapid recognition, prompt intensive care admission, and treatment with intravenous levothyroxine and hydrocortisone. 2

Documentation considerations

Clinical evaluation for this condition should include a detailed history of thyroid dysfunction, thyroid hormone use, adherence to prescribed medication, prior thyroid surgery, and exposure to drugs known to influence thyroid function. 2

A high index of clinical suspicion for myxedema coma is important for timely diagnosis, and prompt initiation of thyroid hormone therapy is paramount when the condition is suspected. 2

What the sources add

While clinical sources detail the severe physiological presentation and intensive care management of myxedema coma, terminology records establish the exact hierarchical position and active status of the E03.5 code. 1 2

Various coding references confirm that E03.5 is the designated ICD-10-CM code for myxedema coma across multiple system versions, including 2018, 2025, and 2026. 1 3 4

Sources

1. ICD-10-CM E03.5 terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-27.
3. E03.5 - Myxedema coma - ICD-10 - Free AI Check — godavaii.com; accessed 2026-07-27.
4. E03.5 — medcode.ch; accessed 2026-07-27.