Pathogenesis. Proctitis is an inflammation of the rectal mucosa. It may be idiopathic or related to a specific cause, such as radiation or gonococcal infection.
Clinical presentation. Patients with proctitis typically complain of pain and bleeding on defecation. Stools may be loose, but often they are well formed. In fact, some patients move their bowels infrequently to avoid pain and thus become constipated, which aggravates symptoms even more. Digital rectal examination may reveal a small amount of bloody stool or mucus. Idiopathic proctitis is a chronic, relapsing, localized condition that progresses to ulcerative colitis in some patients. The appearance of an erythematous, friable, sometimes hemorrhagic mucosa, however, is indistinguishable from that of ulcerative colitis. Small ulcerations and pus suggest the possibility of gonococcal proctitis. Ulcers and vesicles of the distal rectum, which may extend to the perianal skin, suggest herpes proctitis.
Diagnostic studies. Sigmoidoscopy shows the inflammation to be limited to the rectum, sometimes within several centimeters of the anus. Mucosal biopsy and culture of rectal secretions should be obtained. More extensive bowel involvement may be documented by barium enema or colonoscopy.
Idiopathic proctitis. Treatment of idiopathic proctitis usually consists of mesalamine enemas (i.e., Rowasa) or suppositories (i.e., Canasa) or steroid enemas once or twice daily (b.i.d.) for 4 to 6 weeks. Patients should be instructed to lie in the left decubitus position and gently insert a suppository or an enema before bedtime and another in the morning after a bowel movement. Some patients require one or two mesalamine or steroid enemas per day for prolonged periods to control symptoms. Patients who have frequent recurrences of proctitis may respond to prophylactic treatment with sulfasalazine (1 to 2 g b.i.d.) or a mesalamine preparation (e.g., Asacol 800 mg three times daily [t.i.d.] or Colazal 2.25g t.i.d.). Steroid or mesalamine enemas also are somewhat effective in treating radiation proctitis.
Infectious proctitis. Treatment of infectious proctitis is directed at the causative agent. For example, gonococcal proctitis typically responds to aqueous procaine penicillin G, 4.8 million units intramuscular (intramuscular), plus 1 g of oral probenecid. For penicillin-allergic patients, tetracycline (orally, 1.5 g followed by 0.5 g four times daily [q.i.d.] for 4 days) is effective.