Look into hypothermia and hyponatremia in a myxedema coma case


Emergency Medicine

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Journal of Clinical and Translational Endocrinology: Case Reports


Background/objective: Given high mortality rates, understanding the management of associated hypothermia and hyponatremia in the myxedema coma remains crucial.

Case report: A 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.

Discussion: Active 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.

Conclusion: Avoid active rewarming in myxedema. Hyponatremia from an SIADH-like syndrome in myxedema coma corrects with fluid restriction and levothyroxine replacement.

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