Internal intussusception (internal rectal prolapse)
Internal intussusception (internal rectal prolapse) causes outlet obstruction with mucus discharge, hematochezia, tenesmus, and constipation. Proctoscopy demonstrates a solitary rectal ulcer at the lead point of the internal prolapse. Treatment consists of increased bulk, stool softeners, and glycerin suppositories. Indications for surgery are chronic bleeding, impending incontinence, and lifestyle-changing symptoms. Surgical options are controversial. The most frequent procedure is transabdominal rectopexy (suture fixation of the rectum to the presacral fascia) and anterior resection of the sigmoid colon if constipation is prominent among the patient’s complaints. Chronic ischemia of the solitary rectal ulcer causes entrapment of mucin-producing cells, eventually resulting in colitis cystica profunda. Treatment is low anterior resection and rectopexy.