Myxedema coma

The ultimate hypothyroid state before death.

Investigations

• T3, T4, TSH
• CBC
• Urea & Creatinine
• Electrolytes (often ↓Na⁺),
• Cultures
• Bool Cortisol level
• Glucose
• ABG for PaO₂

Management : Preferably on ICU

1. High-flow O2 if cyanosed.
2. Ventilation may be needed.
3. Correct any hypoglycemia.
4. Give T3 (liothyronine) 5–20mcg/12h IV slowly. Be cautious: you may precipitate manifestations of ischemic heart disease. Alternative regimens involve levothyroxine.
5. Give hydrocortisone 100mg/8h IV—vital if pituitary hypothyroidism is suspected (i.e. no goitre, no previous radioiodine, and no previous thyroid surgery).
6. If infection suspected, give antibiotic, e.g. co-amoxiclav 1.2g/8h IV.
7. Caution with fluid, rehydrate as needed but watch for cardiac dysfunction; BP may not respond to fluid and inotropes may be needed.
8. Active warming (blankets, fluids) may be needed for hypothermia. Beware complications (hypoglycemia, pancreatitis, arrhythmias).
9. Further ℞:
   1. T3 5–20mcg/4–12h IV until sustained improvement (~2–3d)
   2. then levothyroxine 50mcg/24h oral.
   3. Hydrocortisone + IV fluids as needed (hyponatremia is dilutional).