Small bowel: Pneumatosis intestinalis

Pneumatosis intestinalis (PI) is the presence of air within the bowel wall and may represent a benign finding of no clinical significance or more serious bowel ischemia. Given the broad spectrum of causes of PI, diagnosis and treatment can be difficult. Clinical scenario, physical examination, radiographic, and laboratory findings all need to be assessed to determine when exploration is necessary. Clinical signs and symptoms necessitating operative intervention are diffuse peritonitis, shock, leukocytosis, and lactic acidosis. Radiographic signs suggesting the presence of ischemia are bowel dilation, mesenteric stranding, and ascites. Once the decision is made to operate, clearly ischemic bowel should be resected, while areas of questionable ischemia can be assessed with Doppler signal, palpation of a mesenteric pulse, and fluorescein evaluation. Rather than overly aggressive resection of marginally viable bowel, the abdomen should be temporarily closed with a planned second-look laparotomy in 24-48 h. When the etiology of PI is the result of a thrombus or embolus, either vascular bypass or embolectomy will need to be performed to minimize the extent of gangrene and need for further resection. In the setting of venous outflow obstruction, anticoagulation must be used expeditiously. Complications of PI associated with bowel ischemia include short bowel syndrome, fistula formation, and prolonged open abdomen with subsequent incisional hernia development.