PSAT303 Fecal Impaction as a Gastrointestinal Prodrome of Myxedema Coma in an Elderly Woman with Multiple Co-morbidities

INTRODUCTION: Fecal impaction is a common occurrence in the elderly, with the most common risk factor being chronic constipation. A common cause of chronic constipation that can be overlooked in the elderly is hypothyroidism. If left untreated, hypothyroidism can have life-threatening manifestations including myxedema coma. In this case report, we describe a rare case of myxedema coma with prodromal fecal impaction. CASE DESCRIPTION: An 87-year-old female with a past medical history of colon cancer status post partial colectomy, stroke, and end stage renal failure (ESRD) requiring hemodialysis, presented to the emergency department with extreme rectal pain. She was found to have fecal impaction on abdominal x-ray and was manually disimpacted and discharged home. Five days later, she presented with altered mental status in the setting of a new active herpes zoster infection and possible pneumonia. She was hypothermic (95F) and hypoxic, needing supplemental oxygen (2 L nasal cannula). Her labs showed hyponatremia (133 mg/dL), hypoglycemia (43 mg/dL), an elevated TSH level (100.0 mIU/ml) and decreased free T4 level (0.9 ng/L). Her EKG showed first-degree AV block with low voltage QRS complexes and her chest x-ray demonstrated bilateral pleural effusions. A CT scan of her head did not show hemorrhage or stroke. Given her classic clinical presentation and lab work findings, myxedema coma was diagnosed and the patient was treated with levothyroxine and hydrocortisone, though she was later transitioned to hospice as per her wishes. DISCUSSION: Chronic constipation is a known etiology of fecal impaction and can be caused by many chronic conditions in the elderly including ESRD, immobility, and hypothyroidism. Fecal impaction is easily identified but the investigation for the etiology is often overlooked. In this case, we argue that patients with an initial presentation of fecal impaction or with severe and unexplained constipation may warrant screening for hypothyroidism as a manageable risk factor for fecal impaction. By doing so, early recognition and treatment of hypothyroidism may prevent potentially fatal patient outcomes such as myxedema coma. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.