Pneumatosis Intestinalis: Cost Paid for Rheumatoid Arthritis Treatment

Abstract

Background: Pneumatosis intestinalis (PI) is the presence of air in the bowel wall. It is a rare complication of chemotherapy; herein we describe a case resulting from treatment with Rituximab. Case description: A 75-year-old woman with rheumatoid arthritis who began Rituximab therapy 8 weeks prior to admission came with 1 week history of abdominal distension and constipation. She was seen in the emergency department 2 days prior to this and X-ray of her abdomen at that time showed bowels filled with stools and was discharged home after enema. She presented again with worsening symptoms and with new radiographic evidence of air in the bowel wall. She had stable vitals and no signs of sepsis. Examination revealed diffuse abdominal discomfort. CT showed pneumatosis in the descending colon without obstruction. Ceftriaxone and metronidazole were started for presumed colitis. Two days after admission, her symptoms improved but she developed leukocytosis of 18*103/uL with 18% bands and Bacteroides bacteremia. Repeat CT abdomen showed pneumatosis extending to the cecum and terminal ileum. On day 5 an exploratory laparotomy was performed, which showed necrotic ascending colon and terminal ileum, and walled off perforation with multiple abscesses. Hemicolectomy with diversion loop ileostomy was performed. Pathological examination of the resected bowel revealed hemorrhagic ischemic bowel wall with ulcerations. Patient recovered well after 35 days of hospital stay. Discussion: Rituximab is a CD20 monoclonal antibody works by inducing antibody and complement mediated cellular cytotoxicity. Rituximab mediated adverse effects including bowel obstruction and perforation, typically occur between 1-77 days after the first dose, as was seen in our patient. Our case is an example of how chemotherapy can mask signs of inflammation. Despite having abdominal perforation and abscess our patient had only mild abdominal discomfort and no other signs of peritonitis. The pathogenesis of PI is unclear. While PI from Rituximab is thought to be secondary to increased mucosal permeability, the ischemic bowel wall in our patient may be due to a direct cytotoxic effect. Conclusion: Since symptoms of perforation may be less evident in patients receiving chemotherapy, clinicians should consider that select patients may need operative intervention, as opposed to conservative management, if they fail to improve.1517 Figure 1 No Caption available.