SAT-361 Myxedema Coma Complicated by Megacolon and Abdominal Compartment Syndrome: A Devastating Consequence of Delayed Treatment

Abstract Disclosure: K. Sargon: None. V. Florova: None. R. Alshantti: None. Introduction: Myxedema coma, a rare andlife-threatening endocrine emergency, occurs at the extreme end ofhypothyroidism, and it can precipitate multisystem failure. Thegastrointestinal (GI) manifestations of hypothyroidism, such as colonicdistension and constipation, are often overlooked due to the precedence ofneurological/neuromuscular and cardiovascular symptoms. In severehypothyroidism, colonic pseudo-obstruction can occur via fecal impaction,resulting in megacolon or intestinal pseudo-obstruction; this may in turn leadto other systems and organs complications. We present a case illustrating thesevere physiological and anatomical GI consequences of untreated congenitalhypothyroidism over an extended period. Case Description: A 53-year-old female withcongenital hypothyroidism, non-adherent to levothyroxine therapy for over adecade, presented with progressive dyspnea and massive abdominal distension. Onadmission, vital signs included bradycardia (51 bpm), blood pressure (110/67mmHg), and oxygen saturation (91% on room air), with a BMI exceeding 50.Laboratory tests revealed severe hypothyroidism (TSH 185 µIU/mL, free T4<0.3 ng/dL). Imaging studies showed multifocal lung consolidation andsignificant colonic stool burden. The initial myxedema score was 50.The patient was started onintravenous glucocorticoids and levothyroxine, as well as antibiotics forpneumonia. However, her condition rapidly deteriorated, necessitatingintubation, vasopressor support, and colonic decompression. The clinical coursewas complicated by sigmoid perforation requiring surgical repair, and acutekidney injury, which in part was attributed to abdominal compartment syndrome,necessitating dialysis. Despite biochemical improvement in severehypothyroidism, multidisciplinary and ICU supportive care, patient’shemodynamic condition remained critical, with poor tolerance to hemodialysis.After a two-week hospitalization, the patient's family elected to transition tocomfort care, and she expired within 24 hours. Conclusion: Our case illustrates thecatastrophic GI consequences of untreated severe chronic hypothyroidism,leading to colonic dysmotility, fecal impaction, and megacolon. The resultingsevere bowel distention and abdominal compartment syndrome precipitatedhemodynamic, respiratory, and renal deteriorations, ultimately culminating in afatal outcome. This serves as a reminder of the challenges of reversingsystemic complications of severe hypothyroidism, even with advanced criticaland multidisciplinary care, and emphasizes the importance of thyroid hormonereplacement adherence in preventing such devastating outcomes in patients withcongenital hypothyroidism or no residual thyroid function. Presentation: Saturday, July 12, 2025