Description

Acute or chronic inflammation of the rectal mucosa

Epidemiology

Incidence

• Predominant age: adults
• Predominant sex: male > female
• Ulcerative colitis (UC): 2 to 19 per 100,000 person-years
• Gonococcal proctitis is most common in individuals <25 years of age.
• People of Jewish descent are 3 to 5 times more likely to have UC.
• Acute radiation proctitis; arises in almost all patients, self-limited, lasts up to 3 months after treatment

Prevalence

• Prevalence of rectal chlamydia and rectal gonorrhea among men who have sex with men (MSM) is 9% and 5%, respectively.
• In children diagnosed with UC:
  • 25% will only have ulcerative proctitis (UP).
  • Girls are twice as likely to have UP than boys.
• >30% of patients with UC have isolated rectal involvement.
• Proximal extension of UP increases from 20% at 5 years to 84% at 20 years.
• Chronic radiation proctopathy (CRP):
  • Onset ranges from 8 to 13 months but can occur many years after radiation exposure.
  • Prevalence is 2–20%.
• Diversion proctitis (DP): Onset is usually from 3 to 36 months after fecal diversion. <50% of patients are symptomatic.

Etiology and Pathophysiology

• Chronic radiation proctitis secondary to ischemic and fibrotic changes
• DP: Proximal fecal diversion causes increased nitrate-reducing bacteria and decreased obligate anaerobes resulting in short-chain fatty acids (SCFAs) deficiency.
• Rectal intercourse in women or MSM can result in proctocolitis.
• Infectious causes:
  • STIs:
    • Gonorrhea; chlamydia; syphilis
    • Herpes simplex virus (HSV; 90% HSV-2)
    • Lymphogranuloma venereum (LGV); chancroid
    • Cytomegalovirus (CMV)
    • Human papillomavirus (HPV)
  • Other:
    • Clostridium difficile
    • Enteric infections, including Campylobacter, Shigella, Escherichia coli, Salmonella, and amebiasis
• Inflammatory causes:
  • UC
  • Crohn disease
• Other causes:
  • Radiation injury
    • Occurs with doses 8 Gy or higher
    • Damage to intestinal cell DNA with helical breaks, inability to replicate and undergo normal cellular repair
    • Acute radiation injury usually occurs within 6 weeks of treatment.
  • Ischemia
  • Vasculitis
  • Toxins (e.g., hydrogen peroxide enemas)
  • Side effects of medications

Genetics

• Higher incidence of UC among certain ethnicities
• In genetically predisposed individuals with dysregulated immune responses, GI infections may increase the risk of UP.

Risk Factors

• STD-related proctitis: HIV-positive MSM with receptive anal intercourse
• UP: protective factors: smoking and appendectomy
  • Risk factors: family history of inflammatory bowel disease (IBD), Jewish ancestry, NSAIDs, bisulfate, estrogen, gastroenteritis, GI dysbiosis, angiogenesis, lymphogenesis, impaired immune responses
• CRP: pelvic radiation, chemotherapy, abdominal surgery, vascular disease, GI angioectasia, AV malformation, smoking, GI dysbiosis, patient comorbidities
• DP; rectal injury; rectal medication use

General Prevention

Safe sex practices; condom use with anal intercourse

Commonly Associated Conditions

• HIV
• Malignancy in patients treated with pelvic radiotherapy