Pneumatosis Cystoides Intestinalis
Primary Pneumatosis Intestinalis

General Considerations

• Gas in the bowel wall
• Occurs as a primary and secondary forms
• Primary form is uncommon and is also called pneumatosis cystoides intestinalis
• Secondary form (85%) occurs with
  • Chronic Obstructive Pulmonary Disease
    • Ruptured blebs allows air to dissect down through retroperitoneum, through mesentery to serosa or submucosa
  • Obstruction to the GI tract
    • Bowel obstruction, such as from carcinoma
• Pyloric Stenosis
• Hirschsprung’s disease
• Necrotizing GI diseases
  • Necrotizing enterocolitis (seen in up to 80% of cases)
• Mesenteric ischemic disease
• Ingestion of caustic materials
• Immunosuppression
  • Transplantation including bone marrow transplants
• AIDS
• Leukemia

Clinical Findings

• Primary form is asymptomatic
• Symptoms of secondary form will depend on the cause

Imaging Findings

• Primary form
  • Multiple, thin walled submucosal or subserosal cysts containing air
    • Air content is high in hydrogen
• Occurs mostly in sigmoid and descending colon
• May mimic polyps when they protrude into lumen on BE or endoscopy
• CT is diagnostic
• Secondary form
• More common in small intestine
• Linear and streak-like rather than cystic
• Parallels bowel wall

Differential Diagnosis

• Stool may mimic the appearance of pneumatosis on conventional radiographs
  • CT will show air in bowel wall on dependent surface in pneumatosis
• Air in the lumen should rise to the highest non-dependent part of lumen

Treatment

• None is usually needed for primary form

Prognosis

• Depends on cause
• Ominous in mesenteric ischemia

Pneumatosis cystoides intestinalis. Air-containing, cystic lucencies
are seen in bowel wall in proximal descending colon (white circle) and in the wall of
the large bowel in the lower abdomen (black arrows). The shape, density and location are characteristic for pneumatosis cystoides intestinalis.
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eMedicine Pneumatosis Intestinalis  Goyal, S; Weltman, D and  Balsam, D