What is the diagnosis and management approach for pediatric patients suspected to have inflammatory bowel disease (IBD)?

Diagnosis and Management of Pediatric Inflammatory Bowel Disease

Initial Diagnostic Approach

For children presenting with chronic diarrhea and abdominal pain without rectal bleeding or perianal disease, combine fecal calprotectin, complete blood count, and C-reactive protein to stratify risk before proceeding to endoscopy. 1, 2

Risk Stratification Using Noninvasive Tests

• Fecal calprotectin ≥250 μg/g has 96% sensitivity for detecting IBD in pediatric patients, making it the single most valuable screening test 2
• Combining fecal calprotectin with blood markers (hemoglobin <-2 SD for age/sex, CRP >10 mg/L) achieves 99.7% accuracy for identifying children requiring endoscopy 2
• Children with normal fecal calprotectin, normal blood inflammatory markers, and normal bowel wall on ultrasound have only 0.09-0.69% probability of IBD, allowing safe reassurance without endoscopy 3, 4
• Intestinal ultrasound showing increased bowel wall thickening provides 96% specificity but only 70% sensitivity, making it useful for confirmation but not exclusion 3

Direct Referral Indications

Immediately refer for endoscopy without waiting for biomarker results if the child presents with: 5, 4

• Rectal bleeding or hematochezia
• Perianal disease (fissures, fistulas, skin tags)
• Palpable right lower quadrant mass
• Persistent fever with gastrointestinal symptoms

Endoscopic Evaluation

Standard Endoscopic Protocol

Perform both ileocolonoscopy and esophagogastroduodenoscopy (EGD) in all pediatric patients undergoing initial IBD evaluation. 6, 1

• Obtain at least two biopsies from six segments: terminal ileum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum 6
• Take biopsies from both abnormal-appearing and normal-appearing mucosa to assess disease distribution 6
• Upper endoscopy is mandatory in pediatric patients because upper GI involvement occurs more frequently than in adults and helps differentiate Crohn's disease from ulcerative colitis 6, 1
• Label biopsies from different segments in separate containers with detailed anatomical site information 6

Histological Features Supporting IBD Diagnosis

• Basal plasmacytosis is the most reliable early histological feature distinguishing IBD from infectious colitis 6
• Architectural changes (crypt distortion, branching, atrophy) indicate chronicity and persist despite clinical remission 6
• Granulomas occur more frequently in pediatric Crohn's disease than adult disease and strongly support the diagnosis 1
• Ulcerative colitis shows diffuse continuous mucosal inflammation starting from the rectum, while Crohn's disease demonstrates focal, discontinuous, transmural inflammation 6

Pre-Treatment Laboratory Screening

Before initiating immunosuppressive therapy, obtain the following mandatory screening tests: 1

• Complete blood count with differential
• Hepatitis B and C serologies
• Varicella zoster virus serology
• Epstein-Barr virus serology
• Tuberculosis screening (interferon-gamma release assay or tuberculin skin test)
• Stool examination for infectious causes including Clostridium difficile toxin 6

Special Consideration for Very Early Onset IBD

Children presenting under age 5-6 years require evaluation for primary immunodeficiency disorders before starting standard IBD therapy. 1, 7

• Very early onset IBD may represent monogenic disorders requiring genomic testing rather than conventional immunosuppression 1, 7
• These patients often have more extensive colitis and may need specialized treatment approaches 1, 7

Treatment Algorithm Based on Disease Severity

Mild to Moderate Crohn's Disease

Initiate exclusive enteral nutrition as first-line induction therapy for mild to moderate pediatric Crohn's disease. 1

• Exclusive enteral nutrition provides a critical window (typically 6-8 weeks) to update vaccination status before starting immunosuppression 1
• Budesonide can be used for mild-moderate disease with appropriate anatomic distribution (ileocecal or right-sided colonic involvement) 1
• Do not use 5-aminosalicylates for induction or maintenance therapy in pediatric Crohn's disease, as evidence does not support efficacy 1

Severe Disease or Poor Prognostic Factors

Initiate biologic TNF antagonist therapy early in patients with severe disease at presentation or poor prognostic factors. 1

• Poor prognostic factors include: persistent severe symptoms despite initial therapy, extensive disease, deep ulcerations, perianal disease, growth failure, or severe endoscopic inflammation 1
• For pediatric Crohn's disease requiring biologic therapy, infliximab 5 mg/kg IV at weeks 0,2, and 6, then every 8 weeks is the standard induction and maintenance regimen 8
• Patients who do not respond by week 14 are unlikely to respond with continued dosing and should be considered for alternative therapy 8

Ulcerative Colitis Treatment

• 5-aminosalicylates are appropriate first-line therapy for mild to moderate ulcerative colitis, particularly left-sided colitis or proctitis 1
• Oral corticosteroids for patients failing 5-ASA therapy; intravenous corticosteroids for severe disease requiring hospitalization 1
• For moderate to severe ulcerative colitis, infliximab 5 mg/kg IV at weeks 0,2, and 6, then every 8 weeks 8

Vaccination Strategy

Update all routine childhood vaccinations during the exclusive enteral nutrition window before starting immunosuppressive therapy. 1

• Complete all inactivated vaccines (influenza, pneumococcal, hepatitis A/B, HPV, meningococcal) before immunosuppression 1
• Withhold all live vaccines (MMR, varicella, rotavirus) once immunosuppression begins 1
• For infants whose mothers received biologics during pregnancy, withhold live vaccines until at least 6 months of age due to transplacental antibody transfer 1

Monitoring and Treatment Targets

Objective Disease Assessment

Target mucosal healing rather than clinical remission alone, as intestinal inflammation often persists despite symptom resolution. 1, 5

• Assess for mucosal healing within 1 year of treatment initiation in patients achieving clinical remission 1
• Fecal calprotectin ≤250 μg/g predicts endoscopic remission with 94% sensitivity and 62% specificity 6
• Calprotectin <100 μg/g reliably indicates absence of mucosal inflammation 9

Pediatric-Specific Monitoring

Monitor growth parameters (height, weight, BMI, pubertal development) at every visit. 1

• Growth failure is a unique pediatric concern requiring aggressive disease control 1
• Monitor bone health including vitamin D and calcium levels; consider bone density assessment in patients with chronic disease or prolonged steroid exposure 1
• Nutritional support is particularly important for children with growth failure and active small bowel disease 1

Differential Diagnosis Considerations

Key Conditions to Exclude

Before confirming IBD diagnosis, systematically exclude: 6, 9

• Infectious colitis: Test for bacterial pathogens (Campylobacter, Salmonella, Shigella), C. difficile toxin, and Giardia in patients with diarrhea 6, 9
• Celiac disease: Measure IgA tissue transglutaminase with total IgA level (>90% sensitivity) 9
• Food allergy-mediated diseases: Consider in younger children with eosinophilic infiltration on biopsy 4
• Meckel diverticulum: Consider in children with rectal bleeding 6

When Diagnosis Remains Uncertain

If initial endoscopy and histology are inconclusive, repeat endoscopic and histologic assessment rather than empirically treating. 6

• Consider wireless capsule endoscopy or enteroscopy for small bowel evaluation if ileocolonoscopy is normal but suspicion remains high 6
• In 10% of pediatric patients, the diagnosis may change between Crohn's disease and ulcerative colitis during the first 5 years 6

Common Pitfalls to Avoid

• Do not rely on CRP alone to exclude IBD, as it lacks sensitivity in pediatric patients and may be normal despite active disease 9
• Avoid falsely elevated fecal calprotectin results by documenting NSAID use within the past 6 weeks, which can cause false positives 9
• Do not perform broad infectious stool panels in children with chronic symptoms lasting >4 weeks without acute illness, as yield is extremely low 9
• Never start immunosuppression in children under 6 years without first evaluating for primary immunodeficiency, as very early onset IBD may represent monogenic disorders 1, 7
• Do not assume clinical remission equals mucosal healing—always verify with objective markers (fecal calprotectin or endoscopy) 1, 5
• Recognize that pediatric IBD often presents with more extensive colitis and upper GI involvement compared to adults, making comprehensive endoscopic evaluation essential 1