Myxedema Coma is an extreme form of hypothyroidism. Consider in all patients with altered mental status, especially with symptoms including: bradycardia, hypothermia, bradypnea, dry skin, sparse hair (can have lateral eyebrow hair loss as a sign), hoarse voice, periorbital edema, or non-pitting edema in extremities. Patient will not actually be in a coma, but will be altered/confused. Mortality approaches 100% without treatment. Lab findings may include hyponatremia, hypoglycemia, respiratory acidosis (hypercapnia).
The diagnosis of myxedema coma will likely not be made until admission. It is important to recognize it as part of your differential diagnosis. If patients are altered, have any of the above symptoms, plus refractory shock to fluids or vasopressors, must start empiric treatment and symptomatic management (treat hypothermia, respiratory distress, etc), on top of initial ED AMS work-up.
Order additional labs, including TSH, free T4, random cortisol level. Give hydrocortisone 100mg IV to cover for underlying adrenal or pituitary insufficiency (give this after random cortisol is drawn - or can give dexamethasone instead, does not interfere with cortisol testing). Levothyroxine (T4) 200-400mcg IV push. Liothyronine (T3) use is controversial, can cause dysrhythmia, follow endocrine recommendations regarding its use if necessary. Theoretically, stress dose steroids should be given prior to levothyroxine so as not to precipitate any possible adrenal crisis, however levothyroxine has a slow onset so as long as both are given in a timely manner, it should not matter.
Patient is to be admitted to the MICU. Diagnosis will likely be made in the MICU, and definitive treatment will require treating the underlying cause. Most likely underlying cause is non-compliance with hypothyroidism medications.
Akash Shah, MD
Department of Emergency Medicine
Lincoln Medical Center
Bronx, NY
Sources:
https://emcrit.org/ibcc/myxedema
https://wikem.org/wiki/Myxedema_coma