A 22 yo male with a history of Asperger syndrome and chronic constipation presents to the Emergency Department with abdominal pain and diarrhea for a week.  On exam he appears uncomfortable, he has tachycardia and a firm, distended, diffusely tender abdomen.  A cat scan is shown below.  What's the diagnosis?  (Scroll down for answer)

Answer: Sigmoid fecal impaction with massive dilation of sigmoid colon (20cm)

• patient at high risk for perforation, taken to the operating room for sigmoidectomy, end-colostomy creation
• the presentation of severe impaction is often similar to that of intestinal obstruction with pain, distension, vomiting and loss of appetite
• risk factors include chronic constipation (metabolic, psychiatric, med-related) as well as functional and anatomic anorectal disorders
• fecal impaction is most commonly seen at the extremes of age - the very young and the elderly
• milder cases are managed with stool softeners, increased fiber and water intake, laxatives, enemas and manual disimpaction if stool is palpable in rectum
• read more on fecal impaction