Anorectal Crohn's disease: surgical and medical management

Abstract

In some patients with Crohn's disease the anorectal complications are the major cause of symptoms and morbidity. Anorectal Crohn's disease may be present in patients with intestinal Crohn's disease, may be the initial manifestation of the disease, or rarely occurs without involvement of Crohn's disease elsewhere in the intestinal tract. The pathogenesis of these anorectal complications remains to be clarified. The anorectal examination is very important in the assessment of patients with suspected or documented inflammatory bowel disease. Meticulous physical examination, examination under anaesthesia and radiological imaging modalities may be utilised to specifically identify the location of abscesses and fistulae. Treatment strategy should be directed toward symptomatic relief; the most important symptom is pain. In most patients this pain will be attributable to an incompletely drained rectal abscess. Simple incision and drainage procedures are often all that is required as initial treatment of anorectal abscesses. Treatment of the anorectal fistulae that occur secondary to Crohn's disease requires combined medical and surgical therapy. Drug therapy is more often initiated for Crohn's disease that involves other areas of the gastrointestinal tract. The anorectal manifestations often respond to these same medications. Lay-open procedures (fistulotomies) are often all that is required surgically for simple (low) anorectal fistulae. High (complex) fistulae that involve large portions of the anorectal muscular ring are more difficult to treat. Patients with these fistulae must be treated on an individual basis, usually local surgical therapy combined with a medical regimen. Many surgical procedures are performed and many classes of medications are utilised on patients with these complex anorectal fistulae. Choosing the appropriate surgical and medical interventions is often quite difficult. Although sulfasalazine, mesalazine and corticosteroids have no lasting or maintenance value for fistulae, the immunosuppressive agents mercaptopurine, azathioprine and cyclosporin, the antibacterial metronidazole and the anti-tumour necrosis factor-alpha monoclonal antibody infliximab have varying degrees of effect. The goal of the combined regimen is to cure the fistula, or at least make it minimally symptomatic, without altering the patient's continence.