Case 64 - Pseudopneumatosis

Summary

Imaging description

Pneumatosis intestinalis (PI) refers to the presence of gas within the wall of the bowel. Pneumatosis intestinalis can be “benign” or life-threatening (Figure 64.1). CT is more sensitive than radiographs for the detection of PI, although the identification of this finding does not mandate surgery [1].

Pseudopneumatosis may resemble PI, but it occurs when intraluminal gas is trapped against the bowel mucosa not within the bowel wall (Figure 64.2). This may occur between mucosal folds, between the mucosa and viscous bowel contents (Figure 64.3), or when bubbles adhere to the mucosa of the bowel. Pseudopneumatosis most commonly occurs in the cecum and ascending colon (Figure 64.4) [2].

Pseudopneumatosis may resemble PI, but it occurs when intraluminal gas is trapped against the bowel mucosa not within the bowel wall (Figure 64.2). This may occur between mucosal folds, between the mucosa and viscous bowel contents (Figure 64.3), or when bubbles adhere to the mucosa of the bowel. Pseudopneumatosis most commonly occurs in the cecum and ascending colon (Figure 64.4) [2].

Importance

The importance of not mistaking pseudopneumatosis for PI is that life-threatening causes of PI, such as mesenteric ischemia, toxic megacolon, acute graft-versus-host diseases, bowel obstruction, and cecal ileus should be considered whenever pneumatosis is identified [3]. The presence of portomesenteric gas and PI is suggestive but not diagnostic of transmural bowel infarction [1, 4]. However, a very large number of “benign” causes have been identified [3]. These are covered more completely in Case 65 and include pulmonary diseases such as obstructive airway disease, cystic fibrosis, and lung transplantation, iatrogenic causes such as placement of percutaneous feeding tubes (Figure 64.5), endoscopic procedures, and corticosteroid administration [3]. Clinical predictors, such as the presence of abdominal distension, peritonitis, and lactic acidemia are most predicative of positive intraoperative findings [5].