What is Pneumatosis Intestinalis
Pneumatosis intestinalis (PI) is a radiographic finding—not a disease—characterized by the presence of gas within the bowel wall, appearing as linear or cystic collections in the submucosa or subserosa. 1
Radiographic Appearance
- Gas appears as linear or bubble-like collections tracking within the bowel wall rather than in the lumen on CT imaging 2
- Plain radiographs show linear or cystic air collections in the intestinal wall, though CT is far more sensitive for detection 3, 2
- Ultrasound may demonstrate echogenic reflections within the bowel wall, but has lower sensitivity than CT 2
Clinical Spectrum: A Critical Distinction
The most crucial task when encountering PI is differentiating benign from life-threatening presentations, as management ranges from outpatient observation to emergency surgery. 1, 4
Life-Threatening PI (Requires Immediate Surgery)
Immediate surgical intervention is mandatory when PI occurs with: 3
- Signs of peritonitis (guarding, rebound tenderness)
- Hemodynamic instability or septic shock
- Free intraperitoneal air suggesting perforation
- Evidence of bowel infarction on imaging
CT findings indicating irreversible ischemia and requiring surgery include: 5
- Intestinal dilatation and wall thickening
- Reduction or absence of bowel wall enhancement
- Portal venous gas (strongly suggests bowel infarction) 5
- Mesenteric stranding or large ascites 5
- Combination of multiple ominous findings
Benign PI (Conservative Management)
Conservative management is appropriate for patients with: 3
- Stable vital signs
- No peritoneal signs
- Normal or near-normal bowel wall enhancement on CT
- Absence of portal venous gas
Treatment consists of: 3
- Bowel rest and nasogastric decompression
- Broad-spectrum antibiotics if bacterial translocation suspected
- Close clinical and biochemical monitoring
Common Clinical Settings
PI occurs in several distinctive contexts: 1
- Premature infants with necrotizing enterocolitis
- Adults with obstructive pulmonary disease
- Immunosuppressed patients receiving chemotherapy, steroids, or post-transplantation 6
- Connective tissue diseases (particularly scleroderma, mixed connective tissue disease) 7
- Mechanical causes: pyloric stenosis, bowel obstruction, colonoscopy-related mucosal injury 2, 1
- Ischemic bowel disease (most important life-threatening cause) 3
Diagnostic Approach
CT scan with contrast is the gold standard for detecting PI and determining its underlying cause. 3, 2 However, in hemodynamically unstable patients with clear peritonitis, do not delay surgery for imaging. 8
Key CT features to assess: 5
- Bowel wall thickness (>4 mm is abnormal) 3
- Pattern of wall enhancement (absent enhancement suggests ischemia)
- Presence of portal or mesenteric venous gas
- Free intraperitoneal fluid or air
- Mesenteric vessel patency
- Associated findings: ascites, mesenteric stranding, splenomegaly
Critical Pitfall
The clinical significance of PI as an isolated finding remains challenging—60% of cases in the largest multicenter study were benign. 5 Do not automatically operate based solely on the radiographic finding of PI or even benign pneumoperitoneum without clinical correlation. 7 Patients with connective tissue disease, immunosuppression, or post-chemotherapy neutropenia frequently have benign PI that resolves with conservative management once myelosuppression recovers. 6, 7
Special Management Considerations
- In inflammatory bowel disease patients with PI: temporarily withhold immunosuppressive medications until acute process resolves 3
- Neutropenic patients post-chemotherapy: conservative management typically succeeds if no secondary complications present, with resolution after myelopoiesis recovery 6
- Small abscesses (<3 cm): treat with IV antibiotics alone 3
- Large abscesses (>3 cm): percutaneous drainage plus antibiotics 3