What is neutropenic colitis?

Neutropenic Colitis: Definition and Management

Neutropenic colitis (typhlitis) is a life-threatening inflammatory condition of the bowel, primarily affecting the cecum and ascending colon, that occurs in neutropenic patients, most commonly following chemotherapy for hematological malignancies, with mortality rates up to 60% when bowel wall thickening exceeds 10mm. 1

Clinical Features and Pathophysiology

Neutropenic colitis typically presents with:

• Neutropenia plus one or more of the following symptoms:
  • Fever
  • Abdominal pain (often in right lower quadrant)
  • Diarrhea
  • Bowel wall thickening 1

The condition most commonly occurs:

• 1-2 weeks after initiation of chemotherapy
• In leukemic patients or those receiving high-dose chemotherapy for solid organ cancers
• With an incidence ranging from 0.8% to 26% among neutropenic patients 1

The pathogenesis is multifactorial, involving:

• Mucosal injury from chemotherapy
• Neutropenia impairing host defense
• Opportunistic intestinal organisms
• Predilection for the ileocecal region 2, 3

Diagnosis

Diagnostic criteria include:

1. Imaging findings:

   • Ultrasound showing bowel wall thickening >5mm (diagnostic)
   • CT scan detection of right colon wall thickening (best diagnostic indicator)
   • High-risk features: fluid-filled bowel, ascites, free fluid between bowel loops, hyperechoic septa in bowel lumen 1

2. Risk stratification:

   • Bowel wall thickening >10mm carries 60% mortality risk
   • Bowel wall thickening <10mm has 4.2% mortality risk 1

3. Laboratory findings:

   • Neutropenia (key diagnostic feature)
   • Fever may be the only sign of abdominal sepsis 4

Management

Treatment of neutropenic enterocolitis should be primarily non-operative, including broad-spectrum antibiotics and bowel rest, with surgery reserved only for patients presenting with signs of perforation or ischemia. 1

Medical Management (First-Line):

1. Antimicrobial therapy:

   • Monotherapy with anti-pseudomonas β-lactam agent, carbapenem, or piperacillin-tazobactam
   • Consider additional antimicrobials if no clinical improvement or specific infection focus suspected
   • Antifungal therapy may be added if fever persists despite antibiotics 1

2. Supportive care:

   • Bowel rest
   • Gastric decompression
   • Fluid and blood product replacement 3

3. Monitoring:

   • Close observation for clinical deterioration
   • Serial imaging if high-risk features present
   • Monitor neutrophil count (recovery correlates with symptom resolution) 1

Surgical Management (Reserved for complications):

Surgery is indicated for:

• Signs of perforation
• Evidence of ischemia
• Continued intestinal bleeding despite correction of coagulopathy
• Free intraperitoneal air
• Uncontrolled sepsis 1, 3

Procedure of choice:

• Right colectomy with ileostomy and mucous fistula
• Primary anastomosis in selected patients 3
• Damage control approach for severely ill patients with physiological derangement 1

Prognosis and Outcomes

• Resolution occurs in up to 86% of patients with conservative antibiotic treatment (median 6-8 days)
• Recovery correlates with rise in neutrophil count after nadir
• Mortality rates:
  • 29.5% overall with positive radiologic signs
  • 60% with bowel wall thickening >10mm
  • 4.2% with bowel wall thickening <10mm 1

Special Considerations

• While most common in patients receiving chemotherapy for hematological malignancies, neutropenic colitis can rarely occur with other medications (e.g., antithyroid drugs, antibiotics) 5, 6
• Atypical presentations with less pronounced symptoms may occur, requiring high clinical suspicion 4
• Emergency symptoms requiring immediate intervention include rapid deterioration despite medical therapy, signs of perforation, massive bleeding, toxic megacolon, and fulminant colitis 4

Pitfalls to Avoid

1. Delaying diagnosis due to atypical presentation or masked symptoms in immunocompromised patients
2. Premature surgical intervention when medical management could be effective
3. Failing to recognize high-risk features on imaging (bowel wall >10mm)
4. Underestimating mortality risk in patients with positive radiologic signs
5. Not considering neutropenic colitis in patients taking medications other than chemotherapy agents