What is the workup for duodenitis?

Workup for Duodenitis

The diagnostic workup for duodenitis should include endoscopy with multiple biopsies from different sites of the duodenum as the primary diagnostic approach, accompanied by comprehensive laboratory testing to rule out infectious and inflammatory causes. 1

Initial Diagnostic Approach

Laboratory Testing

• Complete blood count (CBC) with differential
• Comprehensive metabolic panel (CMP)
• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) as inflammatory markers 1
• Stool studies:
  • Culture for bacterial pathogens
  • Clostridium difficile toxin assay
  • Ova and parasites examination
  • Viral studies if clinically indicated 1
• Helicobacter pylori testing (stool antigen test, urea breath test, or serology) 1

Endoscopic Evaluation

• Upper endoscopy (esophagogastroduodenoscopy) with multiple biopsies is the gold standard for diagnosis 1
• Obtain at least 4-6 biopsies from different sites of the duodenum, including:
  • Duodenal bulb (1-2 samples)
  • Distal duodenum (at least 4 samples) 1
• Biopsies should be immediately fixed in formaldehyde-based fixative 1
• Endoscopic findings may include:
  • Erythema and nodularity
  • Erosions and friability
  • Congested and irregular areas of duodenal bulb mucosa 2, 3

Histopathological Assessment

• Histological evaluation should assess:
  • Presence of inflammatory cell infiltrates (neutrophils, lymphocytes, plasma cells)
  • Epithelial cell atypia
  • Villous architecture
  • Presence of gastric metaplasia 2, 4
• Serial sectioning of biopsy specimens is superior to step sectioning for detecting mild or focal lesions 1

Additional Testing Based on Clinical Suspicion

For Suspected Inflammatory Bowel Disease

• Fecal calprotectin and lactoferrin as non-invasive markers of intestinal inflammation 1
• Consider colonoscopy with ileoscopy to evaluate for concurrent colonic involvement 1

For Suspected Celiac Disease

• Serological testing:
  • IgA tissue transglutaminase antibodies
  • Total IgA level (to rule out IgA deficiency)
  • If IgA deficient, IgG-based testing should be performed 1
• HLA-DQ2 and HLA-DQ8 testing in select cases 1

For Suspected Malignancy

• Endoscopic ultrasound to evaluate regional lymph nodes and duodenal wall infiltration if lymphoma is suspected 1
• CT scan of chest, abdomen, and pelvis if systemic disease is suspected 1

Special Considerations

For Immune Checkpoint Inhibitor-Related Duodenitis

• Additional workup should include:
  • Screening for viral hepatitis (A, B, C)
  • HIV testing
  • TB testing if biologic therapy is being considered 1

For Suspected MALT Lymphoma

• Fluorescence in situ hybridization studies for detection of t(11;18)(p21;p21) 1
• Immunohistochemistry panel including CD20, CD10, CD5, and cyclin D1 1

Follow-up Recommendations

• For patients with confirmed duodenitis:
  • Repeat endoscopy in 8-12 weeks after treatment to assess healing 5
  • Monitor for development of duodenal ulcers, as approximately 48% of patients with duodenitis may progress to ulcer disease 5

Common Pitfalls to Avoid

1. Failing to obtain adequate number of biopsies from different sites of the duodenum
2. Not testing for H. pylori, which is a common cause of duodenitis
3. Overlooking medications that may cause duodenitis (NSAIDs, aspirin, alcohol)
4. Missing celiac disease by not performing appropriate serological testing
5. Failing to consider immune-mediated duodenitis in patients on immune checkpoint inhibitors

By following this comprehensive diagnostic approach, clinicians can accurately diagnose duodenitis and identify its underlying cause, leading to appropriate treatment and improved patient outcomes.