Myxedema coma
Myxedema coma is one of a long list of “misnomer” diagnoses in medicine; patients with the condition are rarely edematous or comatose - Stuart P. Swadron

image by: Mikael Häggström
HWN Suggests
Myxedema Coma: Don't get myxed up
Myxedema coma is severe hypothyroidism leading to decreased mental status and slowed metabolism of multiple organs. It is a medical emergency with a high mortality rate. It is thankfully very rare nowadays, but still very popular in medical school and on boards. We should have named this document “severe hypothyroidism”, but that would not grab as much attention would it? So yes, we misled you to get more viewers (#sorrynotsorry).
Featured
A New Look at Thyroid Emergencies Part I: Myxedema Coma
Myxedema coma is one of a long list of “misnomer” diagnoses in medicine; patients with the condition are rarely edematous or comatose. Dr. LoPresti prefers to use the term “decompensated hypothyroidism”. And it is decompensated hypothyroidism that we as ER Docs need to identify and treat in the emergency department.
Understanding Myxedema Coma
Most common cause: Thyroid supplementation nonadherence – check external medication history.
Articles of Interest
Decompensated Hypothyroidism
HYPOeverything – hypotension, hypoglycemia, hyponatremia, hypoventilation, *hypocardia*, bradycardia but hypocardia sounded cooler.
Decompensated hypothyroidism (myxedema coma)
Levothyroxine (T4) 200-400 mcg IV. (Consider a lower dose in elderly patients and those with significant cardiac disease). (Bridwell 2021; Farkas 2016; Jonklaas 2014) Because T4 is the inactive form of the hormone, it is safe to give this dose empirically if there will be a delay in obtaining lab results.
Decompensated hypothyroidism: An EM Primer
If thyroid labs don’t come back in timely fashion, proceed with thyroid replacement.
EM@3AM: Decompensated Hypothyroidism
The diagnosis of myxedema coma is a clinical diagnosis based upon history and physical examination findings and exclusion of other causes of coma. As with other causes of hypothyroidism, the TSH is typically high while T4 and T3 are low.
Myxedema Coma
Moral of the story…always remember the thyroid!
Myxedema Coma: A Forgotten Medical Emergency With a Precipitous Onset
Myxedema coma (MC) is a rare disorder characterized by severe hypothyroidism, presenting as altered mental status, hypothermia, and a decrease in the function of multiple organ systems. MC is a life-threatening condition with a high mortality rate; rapid recognition is critical to avoid end-organ damage.
POTD: Myxedema Coma
Clinical Features (Remember LOW and SLOW: low HR, BP, Temp, sugar, RR, Na, Mentation, reflexes):
Resources
EMCrit
“Myxedema Coma” is a misleading term: Most patients aren't truly comatose (but they are generally delirious).
Life in the Fastlane
T4 – loading dose = 500mcg IV -> 50-100mcg OD IV or orally.

