Case Presentation: A 64-year-old female with past medical history of seizures, breast cancer s/p bilateral mastectomy, hypothyroidism, anxiety and agoraphobia on Xanax, tobacco abuse presents to ED after husband found her unresponsive, with agonal breathing, slurred speech, and oral secretions. Last admission in 2019 was significant for Xanax and Benadryl overdose. On admission, vitals were 92 F, 35 bpm, 130/60, RR 24, and saturating 82% on room air. Physical exam was pertinent for obese, pale, and lethargic female with GCS of 10, withdraws to pain, with gurgling present due to oral secretions. On auscultation, bradycardic without murmurs, and decreased air movement with bilateral wheezing noted. Bilateral pitting edema was also present. Labs revealed Na 123, HCO3 41, BNP 164, TSH 40, T4 < 0.25, CK 1729. ABG was pH 7.19 and pCO2 63.8, with UDS positive for benzos. Imaging showed moderate bilateral pulmonary edema with effusions and bibasilar atelectasis, and echocardiogram revealed 60% LVEF with grade II diastolic dysfunction. Patient was intubated for airway protection, given atropine for bradycardia and had become hypotensive requiring norepinephrine. Given IV Lasix as well as nebulizer treatments, and VEEG did not reveal seizure activity. Started on IV levothyroxine and solumedrol, with significant improvement in clinical and mental status over the next day. Subsequently extubated and TSH improved to 23 with T4 0.38. Patient had admitted due to her agoraphobia, she was unable to pick up her levothyroxine.

Discussion: Myxedema coma is an endocrine emergency with mortality as high as 30-50%. While rare, population is often in elderly females over 60, such as our patient. Despite the terminology, mental state varies from confusion to lethargy to coma (1). Hypoventilation from decreased respiratory drive leads to hypoxic hypercapnic respiratory acidosis, but airway can be complicated by myxedema of the tongue and pharynx. Hypothermia results from loss of thyroid hormone regulated thermogenesis, and can correlate with mortality. These hemodynamic changes make it critical to start appropriate treatment and monitoring, usually with IV levothyroxine and steroids in the ICU (2).

Conclusions: In the setting of acute encephalopathy, it is important to consider severe hypothyroidism on the differential and have a low threshold for critical care support given the necessity for cardiopulmonary monitoring. Psychosocial factors certainly play a role in medication compliance and future prevention.