Background: Pneumatosis intestinalis (PI), characterized by subserosal or submucosal cysts of the GI tract, is an unusual and concerning finding. While it can exist in a benign setting, its appearance in certain patients can indicate ischemic bowel and the need for immediate surgical intervention. We present the largest series of consecutive cases of PI to illustrate surgical indications and risk factors associated with death.
Methods: We systematically reviewed the radiology database of the Mount Sinai Medical Center for cases of PI that occurred between 1996-2006 in patients ≥ 15 years of age. Through a retrospective cohort study, we acquired information on associated conditions (within the categories of inflammatory, autoimmune, infectious and pulmonary disorders), presenting symptoms (such as vomiting, pain and diarrhea) laboratory results, and radiological findings (bowel wall characteristics, portal venous and free air). Univariate and multivariate analyses were then used to identify significant risk factors.
Results: Forty patients developed PI over a ten year span. The average age was 53 years old, and cases were distributed between 23 males (57%) and 17 females (43%). The overall surgical and mortality rates were 35% and 20% respectively. Of the 8 patients who died, 50% had surgical intervention and 50% were treated conservatively. The most common condition associated with PI was immunosuppression (42.5%), most common associated symptom was pain (82.5%), and most common associated radiologic finding was thickened bowel (40%). Statistically significant (p < 0.05) surgical predictors were portal venous gas, pain, vomiting, age > 60, and low calcium (7.7 vs. 8.6 mg/dL). On multivariate analysis, both age > 60 (OR = 37.8, 95% CI: 2.4-590, p = 0.04) and vomiting (OR = 14.4, 95% CI: 1.2-204, p = 0.05) remained independently associated with surgery. On univariate analysis, significant risk factors for mortality were infection, immunosuppression, liver disease, sepsis, thickened bowel and low bicarbonate (18.9 vs. 23.7 mmol/L). Multivariate analysis that controlled for surgical status revealed thickened bowel to be independently associated with mortality (OR = 26.7, 95% CI: 1.1-645.2, p= 0.04).
Conclusion: PI is a rare condition that can indicate ensuing mortality. It is therefore imperative to identify the subset of patients with PI who can benefit from surgery and avoid a severe outcome. The combination of PI and vomiting in the elderly patient group mandates expedient surgical consultation, and the radiologic presence of thickened bowel in the setting of PI suggests a dismal prognosis irrespective of surgical status.