- The exact cause of inflammatory bowel disease (IBD) is unknown. Proposed causes include infectious, genetic, and environmental factors, as well as immune dysregulation.
- Ulcerative colitis (UC) is confined to the rectum and colon, causes continuous lesions, and affects primarily the mucosa and the submucosa. Crohn’s disease (CD) can involve any part of the GI tract, often causes discontinuous (skip) lesions, and is a transmural process that can result in fistulas, perforations, or strictures.
- Common GI complications of IBD include rectal fissures, fistulas (CD), perirectal abscess (UC), toxic megacolon (UC), and colon cancer. Extraintestinal manifestations include hepatobiliary complications, arthritis, uveitis, skin lesions (including erythema nodosum and pyoderma gangrenosum), osteoporosis, anemia, and aphthous ulcerations of the mouth.
- The severity of UC may be assessed by stool frequency, presence of blood in stool, fever, pulse, hemoglobin, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), abdominal tenderness, and radiologic or endoscopic findings. The severity of CD can be assessed using similar parameters, in addition to the CD Activity Index, which includes stool frequency, presence of blood in stool, endoscopic appearance, and physician’s global assessment.
- The goals of IBD treatment are resolution of acute inflammation and complications, alleviation of systemic manifestations, and maintenance of remission.
- The first line of treatment for mild to moderate extensive UC consists of oral aminosalicylates with oral controlled release budesonide as an alternative. Mesalamine or steroid enemas or suppositories may be used for distal disease. Mesalamine is less effective for CD; however, certain delayed-release oral formulations of mesalamine may be used for Crohn’s ileitis. Controlled-release budesonide is preferred as a first-line agent for CD confined to the terminal ileum and/or ascending colon.
- Systemic corticosteroids are often required for acute UC or CD. The duration of steroid use should be minimized and the dose tapered gradually over 3 to 4 weeks.
- Infliximab or adalimumab is a treatment option for patients with moderate to severe active UC and for those patients with UC who are corticosteroid dependent. Azathioprine or mercaptopurine may be used for maintenance of remission as an alternative to or in combination with infliximab for patients with UC who have failed aminosalicylates and for patients who are corticosteroid dependent.
- IV continuous infusion of cyclosporine may be effective in treating severe colitis that is refractory to corticosteroids as an option to delay or prevent the need for surgery.
- Aminosalicylates can prevent recurrence of acute UC in many patients, while steroids are ineffective for this purpose.
- Other treatments for CD include infliximab, adalimumab, and certolizumab (for moderate to severe or fistulizing disease as both induction and maintenance therapies); methotrexate, azathioprine, or mercaptopurine (for inadequate response or to reduce steroid dosage and in combination with infliximab); metronidazole (for perineal or colonic disease); natalizumab (for patients failing tumor necrosis factor-α [TNF-α] antagonists); and cyclosporine (for refractory disease).
On completion of the chapter, the reader will be able to:
Characterize the epidemiologic difference between ulcerative colitis (UC) and Crohn’s disease (CD).
Discuss the proposed ...