Look into hypothermia and hyponatremia in a myxedema coma case

Abstract

Background/objectiveGiven high mortality rates, understanding the management of associated hypothermia and hyponatremia in the myxedema coma remains crucial. Case reportA 69-year-old Caucasian male from New England with no known medical history presented to the hospital after a mechanical fall. He was lethargic but arousable on presentation. The vitals showed a rectal temperature of 84.9 °F, heart rate of 48 beats/minute, and blood pressure of 139/87 mmHg. He had delayed reflexes. Active rewarming was initiated to treat hypothermia which led to hypotensive episodes. Initial studies showed TSH of 52 uIU/ML (0.35–5.5), undetectable free T4, and he was treated with intravenous stress-dose glucocorticoids and levothyroxine. Hypotension was partially responsive to fluid therapy but required norepinephrine infusion later. Septic and cardiogenic shock were ruled out retrospectively.He had serum sodium of 117 MEQ/L, serum osmolality of 255 mOSM/KG), urine sodium of 29 MEQ/L, and urine osmolality of 529 mOSM/KG. Hyponatremia improved with levothyroxine replacement and fluid restriction, suggestive of an SIADH-like syndrome. Further studies revealed positive thyroid peroxidase and thyroglobulin antibodies. A neck ultrasound revealed a partially visualized atrophic thyroid gland. DiscussionActive rewarming to treat hypothermia in myxedema can lead to hemodynamic instability. Studies report a weak association between hypothyroidism and hyponatremia. Severe hyponatremia from an SIADH-like syndrome can occur in myxedema. ConclusionAvoid active rewarming in myxedema. Hyponatremia from an SIADH-like syndrome in myxedema coma corrects with fluid restriction and levothyroxine replacement.