Pneumatosis Intestinalis Due to Mycobacterium avium intracellulaire in an AIDS Patient

Abstract

Pneumatosis intestinalis (PI) is characterized by the presence of multiple submucosal and subserosal blood-filled cysts in the small or large intestine. PI associated with AIDS is usually asymptomatic, but uncommonly causes life-threatening disorders potentially producing bowel necrosis or perforation. We report a patient with Mycobacterium avium intracellulaire (MAI) and complicated PI to alert clinicians to consider this rare and potentially misleading cause of abdominal complaints when evaluating clinical symptoms in AIDS. Case report: A 41 y.o. man with AIDS (CD4 = 7) presented to the ER with 2 months of diffuse upper abdominal pain, diarrhea and weight loss. On exam, he was afebrile and had a distended, tender upper abdomen without signs of peritonitis. WBC = 2500 with 85% polys. Abdominal CT scan = widespread lymphadenopathy consistent with disseminated MAI, diagnosed previously. Abdominal pain decreased over several days, but loose, watery diarrhea persisted. On hospital day 10, his pain worsened acutely and new diffuse abdominal tenderness was detected; he remained afebrile with no change in WBC. Repeat CT scan demonstrated extraluminal, submucosal air consistent with pneumatosis of the right colon and sigmoid; a small amount of free intraperitoneal air indicative of intestinal perforation was suggested. He underwent exploratory laparotomy, sub-total colectomy and small bowel resection with ileostomy for severe colitis. Pathology revealed MAI of the ileum, colon and pericolonic mesenteric lymph nodes. No perforation was present. Discussion: PI has been reported in AIDS and other immunosuppressed settings, including solid organ transplantation, chemotherapy, and high-dose corticosteroid treament. Opportunistic infections such as CMV, toxoplasmosis, MAI and cryptosporidium are the most common associations of PI in AIDS which may represent as many as 10–25% of all PI cases. Most frequently, PI in AIDS is incidental and resolves or stabilizes with conservative mangement. Our patient, however, developed worrisome signs and symptoms requiring laparotomy. Clinicians must be aware that the spectrum of MAI-associated PI in AIDS is diverse. This rare disorder may manifest as an incidental imaging finding, or as unexplained digestive symptoms which may be innocuous or life-threatening. Free intraperitoneal air in this setting may be due to rupture of a subserosal bleb resulting in non-surgical pneumoperitoneum or reflect an intra-abdominal emergency.