What is the appropriate clinical evaluation and management of jejunal wall thickening identified on computed tomography in an adult patient?

Clinical Evaluation and Management of Jejunal Wall Thickening on CT

Jejunal wall thickening identified on CT imaging requires systematic characterization of imaging features followed by endoscopic evaluation with enteroscopy or MR enterography, as endoscopy reveals significant pathology in 67% of cases with bowel wall thickening. 1

Initial Imaging Characterization

When jejunal wall thickening is detected, the radiologist should systematically assess the following features to narrow the differential diagnosis:

Measure Wall Thickness

• Wall thickness ≥10 mm indicates severe inflammation, while 5-9 mm represents moderate inflammation 2, 3
• Normal jejunal wall measures <3 mm 4

Assess Distribution Pattern

• Focal thickening (<5 cm) favors neoplasm or localized inflammatory process 4
• Segmental or diffuse involvement (>5 cm) suggests inflammatory bowel disease, ischemia, or infectious enteritis 4

Evaluate Symmetry and Enhancement

• Asymmetric thickening, particularly affecting the mesenteric border, is highly specific for Crohn's disease 5, 2, 3
• Smooth, symmetric, circumferential thickening suggests benign processes including edema, ischemia, or infectious enteritis 2
• Stratified enhancement with submucosal edema indicates active Crohn's disease inflammation 3, 6

Look for Associated Findings

• Small ulcerations visible on contrast-enhanced images indicate severe inflammation 5, 3
• Perienteric fat stranding disproportionately more severe than wall thickening suggests inflammatory conditions rather than malignancy 4
• Mesenteric stranding and "comb sign" support active Crohn's disease 5

Differential Diagnosis Based on Imaging Pattern

For Asymmetric Thickening with Inflammatory Features

Crohn's disease is the primary consideration when asymmetric wall thickening is present with mesenteric border involvement, stratified enhancement, and perienteric changes 5, 2

For Smooth Symmetric Thickening

Consider:

• Infectious enteritis 2
• Ischemic bowel disease 5, 2
• Edematous processes (hypoalbuminemia, portal hypertension) 2
• Lymphoma (can present with symmetric thickening) 4

Critical Findings Requiring Urgent Intervention

The presence of extraluminal air, contrast extravasation, or bowel wall defects warrants prompt surgical exploration 5

Recommended Diagnostic Algorithm

Step 1: Advanced Cross-Sectional Imaging

MR enterography with oral and IV contrast is the preferred next step when Crohn's disease is suspected, offering sensitivity of 66-95% and specificity of 64-97% for detecting small bowel inflammation 3, 6

MRE should be prioritized over repeat CT, particularly in patients under 35 years old, to avoid radiation exposure 5

Key MRE sequences to assess:

• T2-weighted imaging with fat saturation to evaluate intramural edema 5
• Diffusion-weighted imaging showing restricted diffusion supports severe inflammation 5, 3
• Post-gadolinium imaging to assess enhancement pattern and identify ulcerations 5

Step 2: Endoscopic Evaluation

Endoscopy (ileocolonoscopy with terminal ileum intubation or enteroscopy) should be performed when imaging shows jejunal wall thickening without a clear diagnosis 2

Endoscopy reveals abnormalities in 67% of patients with bowel wall thickening on CT and enables targeted biopsy for histologic diagnosis 1

For jejunal involvement specifically:

• Push enteroscopy or device-assisted enteroscopy (balloon or spiral) may be required to reach the jejunum 2
• Video capsule endoscopy can be considered but does not allow biopsy 5

Step 3: Laboratory Evaluation

Obtain:

• Complete blood count, inflammatory markers (CRP, ESR) 5
• Stool cultures and serologies for infectious pathogens if infectious enteritis is suspected 2, 3
• Fecal calprotectin if inflammatory bowel disease is being considered 5

Management Based on Diagnosis

If Crohn's Disease is Confirmed

Initiate therapy based on severity of inflammation, with severe inflammation (wall thickness ≥10 mm, ulcerations, restricted diffusion) requiring aggressive medical therapy including biologics for moderate-to-severe disease 2

If Ischemia is Suspected

Urgent surgical consultation is required to assess for reversible causes versus transmural infarction requiring resection 2

If Infectious Enteritis is Likely

Obtain stool cultures and consider empiric antibiotics if bacterial infection is suspected 2

If No Diagnosis After Initial Workup

In patients with equivocal findings, repeat imaging after 6 hours if clinical signs evolve, or consider observation with clinical follow-up if stable 5

Important Clinical Pitfalls

• Do not assume smooth symmetric thickening is always benign—lymphoma and well-differentiated adenocarcinoma can present this way 4
• Jejunal Crohn's disease can be present with normal ileocolonoscopy, as proximal small bowel involvement may be isolated 5
• Free peritoneal fluid without solid organ injury on trauma CT has only 53% sensitivity but 81% specificity for bowel injury 5
• Clinical parameters alone cannot reliably predict endoscopic findings in patients with bowel wall thickening 1