Pediatric Crohn’s Disease

Crohn disease (CD), or Crohn’s disease, is a chronic inflammatory bowel disease. Once considered rare in the pediatric population, Crohn disease is recognized with increasing frequency among children of all ages. Approximately 20-30% of all patients with Crohn disease present when they are younger than 20 years.

Pathophysiology
The pathogenesis of Crohn disease is multifactorial. After a triggering event occurs in a genetically susceptible individual, an altered immune response leads to chronic inflammation of the intestine. Although the etiology of the precipitating event is unknown, luminal bacteria or specific antigens are thought to be involved.

The macroscopic findings at the time of endoscopy and colonoscopy or surgery include various degrees of edema, erythema, ulceration, friability, thickening of the bowel wall and mesentery, and extension of fat over the serosal surface of the intestine.

Skipped areas of inflammation anywhere in the upper or lower GI tract are characteristic of Crohn disease, in contrast to the continuous diffuse colonic inflammation found with ulcerative colitis(UC). Microscopic findings on intestinal mucosal biopsy consist of chronic inflammation with architectural distortion. Granulomas are sometimes noted on biopsy findings in Crohn disease.

Clinical PresentationPatients with suspected Crohn disease (CD), or Crohn’s disease, should initially be evaluated by their primary care team. The patients’ symptoms should be elicited in detail. A medical history, detailed review of systems, and family history should be obtained, and growth parameters should be documented.

A careful assessment of growth and development is an important part of evaluating the pediatric patient. Growth abnormalities may be detected by evaluating several parameters: height and weight, percentage height and weight for the patient’s age and percentage weight for the patient’s height, growth velocity, body composition on anthropometry, and skeletal bone age.

• Vital signs are usually normal, although tachycardia may be present with anemic patients. Chronic intermittent fever is a common presenting sign.
• Body weight and height may reveal weight loss and growth delay.
• Abdominal findings may vary from normal to those of an acute abdomen. Diffuse abdominal tenderness is often present. Fullness or a discrete mass may be appreciated, typically in the right lower quadrant of the abdomen, which may represent a palpable thickened loop of bowel.
• Perianal disease (eg, skin tags, abscesses, fistulae, fissures) is present in approximately 45% of patients.
• Pubertal delay may precede the onset of intestinal symptoms, and accurate Tanner staging should be a part of routine physical examination.
• The most common cutaneous manifestations of Crohn disease are erythema nodosum and pyoderma gangrenosum. Skin examination may also reveal pallor in patients with anemia or jaundice in those with concomitant liver disease.
• Eye examination may reveal episcleritis. For the diagnosis of uveitis, a slit lamp examination by an experienced physician is necessary.

The most common extraintestinal manifestations of Crohn disease are arthritis and arthralgia. The large joints (eg, hips, knees, ankles) are typically involved.

Treatment
The general goals of treatment for children with Crohn’s disease, are

(1) to achieve the best possible clinical, laboratory, and histologic control of the inflammatory disease with the least adverse effects from medication;

(2) to promote growth with adequate nutrition; and

(3) to permit the patient to function as normally as possible (eg, in terms of school attendance, participation in activities).

5-ASA preparations
Although commonly used, recent adult meta-analyses have suggested that oral 5-ASA preparations do not demonstrate clinically important treatment effect for active Crohn disease and are not superior to placebo for the maintenance of remission in Crohn disease.

Nutritional therapy
Nutritional therapy is another important modality for the treatment of disease, malnutrition, and growth failure observed in Crohn disease.

Corticosteroids
These are the mainstay of therapy for acute exacerbations because they suppress acute inflammation, thereby providing rapid symptomatic relief.

Immunomodulators
Immunomodulators have been used to induce and maintain long-term remission in chronically active, steroid-dependent or steroid-refractory, moderate-to-severe pediatric Crohn disease.

Antibiotics
A few, small studies have shown the usefulness of antibiotic therapy in the treatment of Crohn disease. Metronidazole, as well as the combination of metronidazole and ciprofloxacin, is useful in both the management of perianal disease and small bowel and colonic disease.