Inflammatory Bowel Disease
Aaron Brzezinski
POINTS TO REMEMBER
It is estimated that approximately 1.5 million Americans have inflammatory bowel disease (IBD).
The presentation of ulcerative colitis (UC) in children is usually with severe and extensive disease, whereas adults usually have milder disease that is limited to the left colon. In adults at presentation, the disease is limited to the rectum in 30% of patients, and in 60% it is distal to the splenic flexure.
Patients with UC usually present with nonbloody diarrhea that progresses to bloody diarrhea.
Stool studies to exclude bacterial and parasitic infections are indicated at the time of initial presentation.
Histology is the most sensitive way of establishing the extent of the disease, and unless there is a contraindication, a colonoscopy with biopsies is indicated in all patients in whom UC is suspected.
The main role of radiologic tests in patients with UC is to exclude complications associated with severe or fulminant disease and to exclude Crohn’s disease.
Most patients with UC have intermittent attacks, with remissions lasting from a few weeks to many years. At presentation, 5% to 10% have a severe attack that requires urgent colectomy, and 10% to 15% of patients have chronic active disease. The course and prognosis are largely determined by the extent of the disease.
Patients with UC and Crohn’s disease of the colon have an increased risk of colorectal cancer.
Patients who have had UC pancolitis for more than 7 to 10 years are advised to undergo surveillance colonoscopies with biopsies.
Crohn’s disease is a heterogeneous disease that has different clinical presentations, which are determined by the site of involvement and disease behavior (inflammatory, stricturing, or fistulizing).
In Crohn’s disease, any segment of the gastrointestinal tract can be involved, but the most common distribution is ileocolic disease that is seen in 50% of patients, small bowel involvement alone occurs in 30%, and colonic involvement alone in 20% of the patients.
Perianal disease occurs in 30% of patients with Crohn’s disease, and approximately 10% of female patients with Crohn’s colitis develop rectovaginal fistulas.
A larger-than-expected number of patients with Crohn’s disease are cigarette smokers.
Contrast studies play a major role in the diagnosis of small bowel and gastroduodenal Crohn’s disease.
In the past decade the new imaging modalities such as computed tomography enterography (CTE) and magnetic resonance enterography (MRE) have become the preferred imaging modalities in the diagnosis of Crohn’s disease.
Distinguishing between UC and Crohn’s disease can be difficult.
About 50% to 60% of patients with IBD have extraintestinal manifestations (EIMs).
The EIMs that parallel disease activity include
Peripheral arthritis
Erythema nodosum
Pyoderma gangrenosum
Keratoconjunctivitis
Episcleritis
Hypercoagulability (if related to thrombocytosis and acute-phase reactants, not if it is related to primary abnormalities in the coagulation system such as protein S, C deficiency, or factor V Leiden mutations)
The EIMs that run a course independent of disease activity include
Ankylosing spondylitis, which more commonly occurs in patients with UC who are HLA-B27 positive
Sacroiliitis
Primary sclerosing cholangitis
Uveitis
Treatment can be divided into two phases: therapy for the acute attack (induction of remission) and maintenance of remission.
Medications used to treat patients with IBD include
5-Aminosalicylic acid (5-ASA)
Antibiotics
Crohn’s disease only
Corticosteroids
Corticosteroids are indicated for induction of remission in patients with moderate or severely active UC or Crohn’s disease, but are not indicated for maintenance of remission.
Immunosuppressive medications
The most commonly used medications in this group are the thiopurines (6-mercaptopurine and azathioprine), and the antimetabolite methotrexate.
Biologic medications
Biologic agents that block tumor necrosis factor-α are indicated for induction and maintenance of remission in IBD patients.
Infections are one of the most common and significant complications of these agents
Between one-third and one-half of patients with IBD require surgery. Patients with UC and extensive Crohn’s colitis require surgery because of failure to respond to medical treatment, hemorrhage, toxic dilatation, perforation, strictures causing obstruction, and dysplasia or cancer.
Depending on the indication, patients with Crohn’s disease may undergo a segmental resection, strictureplasty, or both.Related posts:
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