What are the causes and treatments of caecal wall thickening?

Causes and Treatment of Caecal Wall Thickening

Caecal wall thickening is most commonly caused by inflammatory conditions, infections, ischemia, or neoplasms, with treatment directed at the underlying cause. Proper diagnosis through imaging and appropriate follow-up investigations is essential for optimal management of morbidity and mortality.

Common Causes of Caecal Wall Thickening

Infectious Causes

• Clostridioides difficile infection (CDI) - characterized by colonic wall thickening >4mm on imaging, often with pericolonic stranding and ascites 1
• Neutropenic enterocolitis (typhlitis) - occurs in neutropenic patients (ANC <500 cells/mL) with bowel wall thickening >4mm, commonly affecting the caecum 1
• Cytomegalovirus (CMV) infection - particularly in immunosuppressed patients 1

Inflammatory Causes

• Inflammatory bowel disease - can cause segmental or diffuse wall thickening 1
• Solitary caecal ulcer syndrome - rare condition presenting with right-sided abdominal pain and haematochezia 2

Ischemic Causes

• Ischemic colitis - characterized by abrupt transition between caecal wall and ascending colon wall, often with central area thickening and possible pneumatosis 3
• Non-neutropenic ischemic colitis - reported with certain chemotherapy regimens like docetaxel 1

Neoplastic Causes

• Colorectal cancer - typically presents as focal, irregular, and asymmetrical wall thickening 4, 5
• Lymphoma - can present as segmental or diffuse wall thickening 4

Diagnostic Approach

Imaging Findings

• CT scan is the preferred imaging modality for initial assessment 1
• Significant caecal wall thickening is typically defined as >4mm 1
• Additional concerning CT findings include:
  • Pericolonic stranding 1
  • Ascites 1
  • Pneumatosis intestinalis 1, 3
  • "Accordion sign" or "double-halo sign" in CDI 1

Pattern Recognition

• Focal (<5cm) thickening - more likely to be neoplastic, especially if irregular and asymmetric 4
• Segmental (6-40cm) or diffuse (>40cm) thickening - more likely inflammatory, infectious, or ischemic 4
• Perienteric fat stranding disproportionately more severe than wall thickening suggests inflammatory condition 4

Treatment Approaches

Infectious Causes

• For C. difficile infection:

  • Discontinue offending antibiotics if possible 1
  • Empirical therapy should be considered while awaiting test results in severe cases 1
  • Avoid unnecessary repeat testing in the absence of clinical changes 1

• For neutropenic enterocolitis:

  • Bowel rest, intravenous fluids, parenteral nutrition 1
  • Broad-spectrum antibiotics 1
  • Normalization of neutrophil counts 1
  • Conservative management when inflammation is limited to caecum and terminal ileum 1
  • Surgical intervention for perforation, persistent bleeding, or clinical deterioration 1
  • Colonoscopy is contraindicated due to high risk of perforation 1

Inflammatory Causes

• Treatment directed at the underlying inflammatory condition 1
• Control of sepsis prior to any abdominal surgery 1
• For intra-abdominal abscesses: intravenous antibiotics and percutaneous image-guided drainage as first-line treatment 1

Ischemic Causes

• Supportive care with close monitoring 3
• Surgical intervention may be necessary in cases of perforation or necrosis 3

Neoplastic Causes

• Endoscopic evaluation is recommended for all patients with gastric or colonic wall abnormalities on CT scan due to the significant risk of cancer 5
• Surgical resection for confirmed malignancies 5

Special Considerations

Follow-up Recommendations

• Ultrasound is useful as a follow-up tool to assess gradual decrease in bowel wall thickening, especially in neutropenic enterocolitis 1
• Mortality risk in neutropenic enterocolitis correlates with wall thickness - thickness >10mm has significantly higher mortality (60%) than thickness ≤10mm (4.2%) 1

High-Risk Populations

• Cancer patients undergoing chemotherapy are at increased risk for neutropenic enterocolitis 1, 6
• Immunosuppressed patients with C. difficile are at high risk of early progression to fulminant toxic megacolon 1
• Elderly patients (≥65 years) are at higher risk for complications from infectious colitis 1

Pitfalls to Avoid

• Relying solely on wall thickening for diagnosis - pattern of thickening and associated findings are crucial 4
• Performing colonoscopy in neutropenic enterocolitis, which carries a very high risk of perforation 1
• Delaying treatment in immunosuppressed patients with suspected infectious colitis 1

Remember that caecal wall thickening is often a non-specific finding, and clinical correlation with laboratory and additional imaging findings is essential for accurate diagnosis and appropriate treatment 4, 5.