Chapter 43 Inflammatory Bowel Disease
PATHOPHYSIOLOGY
Ulcerative colitis (UC) and Crohn’s disease (CD) are two major idiopathic inflammatory bowel disease (IBD) in children, with 15% falling in the indeterminate IBD category. They share many common characteristics such as diarrhea, pain, fever, and blood loss. The etiologies of both diseases are unknown, although recent research has focused on genetic (IBD disease gene on chromosome 16 [CARD15]), immunologic, dietary, and infectious causes. Some research implicates the presence in IBD of specific infectious agents such as Bacteroides fragilis, Mycobacterium paratuberculosis, paramyxoviruses, and Listeria monocytogenes; Campylobacter jejuni, Salmonella, Shigella, Yersinia, and Eschericia coli have also been associated with relapses of IBD. The single greatest risk factor for IBD is a positive family history (found in 15% to 30% of IBD patients). To date, there is no indication that emotional factors are the primary cause. The goal of therapy includes control of inflammation and associated signs and symptoms, improving nutritional status to allow optimal growth and sexual maturation, and good quality of life—both emotionally and physically.
An association between ankylosing spondylitis and the histocompatibility of human leukocyte antigen (HLA-B27) and inflammatory bowel disease is a possibility. Ulcerative colitis and Crohn’s disease have similar initial signs, including diarrhea, rectal bleeding, abdominal pain, fever, malaise, anorexia, weight loss, and anemia. Children may initially be seen with vague symptoms such as growth failure, anorexia, fever, and joint pains with or without gastrointestinal symptoms. Both conditions are characterized by remissions and exacerbations. Extracolonic manifestations such as joint problems, hepatobiliary conditions, skin rashes, and eye irritation can occur. Although the peak incidence of inflammatory bowel disease is between 15 and 25 years of age, 15% of all cases occur at age 15 years and younger. Prognosis is dependent on the following factors: (1) age at onset and rapidity of onset; (2) response to medical treatment; and (3) extent of involvement.
Ulcerative colitis is a recurrent inflammatory and ulcerative disease affecting primarily the large intestine. Lesions are continuous and involve the superficial mucosa, causing vascular congestion, capillary dilation, edema, hemorrhage, and ulceration. Muscular hypertrophy and deposition of fibrous tissue and fat result, which gives the bowel a “lead pipe” appearance because of narrowing of the bowel itself.
Crohn’s disease is an inflammatory and ulcerative disease affecting any part of the alimentary tract from the mouth to the anus. Rectal pain and bleeding from fissures and fistulas occurs in 25% of CD patients. Of CD patients, 10% have proctitis, and 70% of these patients will develop more extensive disease. The CD affects the deep walls of the bowel. The lesions are discontinuous, resulting in a “skipping” effect, with the diseased portions of the bowel separated by normal tissue. Fissures, fistulas, and thickened intestinal walls result. Granulomas occur in approximately 50% of cases.
INCIDENCE
1. Annual incidence of UC and CD is 4 to 10 cases in 100,000 children; 2 to 14 cases occur in 100,000 in the general population. IBD affects male and female equally.
2. Ulcerative colitis represents more than half of the 20,000 to 25,000 newly diagnosed cases of IBD each year.
3. Age range of peak incidence is 15 to 25 years.
4. White individuals are affected more often than African-American individuals; IBD not seen in third-world countries.
5. A high preponderance of cases occur in American Jews.
6. Of those with ulcerative colitis, 29% have a family history of the disease.
7. Of those with Crohn’s disease, 35% have a family history of the disease.
CLINICAL MANIFESTATIONS
Ulcerative Colitis
1. Frequent, bloody stools (number of stools varies from 4 to 24)—major symptom
2. Pain relief after defecation
4. Anorexia, pallor, and fatigue
9. Ten- to 20-pound weight loss over 2 months
10. Anemia, leukocytosis, increased erythrocyte sedimentation rate
11. Extraintestinal symptoms—skin rashes, arthritis
COMPLICATIONS
LABORATORY AND DIAGNOSTIC TESTS
1. Complete blood count—anemia
2. White blood cell count—increased with inflammation
3. Erythrocyte sedimentation rate—increased with inflammation
4. Hematocrit—decreased because of blood loss
5. Serum electrolyte levels—decreased potassium
6. Serum protein level—decreased proteins
7. Stool culture—for presence of infectious organisms
8. Hematest of stool—for presence of blood in stool
9. D-Xylulose absorption blood and urine test—to measure intestinal absorption when there are fatty stools
10. Sigmoidoscopy—to evaluate mucosa, rectum, sigmoid colon directly
