1890 An Attack of Disseminated MAC

Abstract

INTRODUCTION: A 43-year-old woman with a past medical history of AIDS presented with a 3 month history of diarrhea, abdominal pain, and weight loss. She was noted to have pancytopenia with a profound anemia. Alkaline phosphatase was elevated with normal AST and ALT. Stool culture, C diff, shiga toxin, and stool cryptosporidium Ag were negative. Mediastinal, axillary, retroperitoneal, and inguinal lymphadenopathy were noted on CT scan with splenomegaly. CASE DESCRIPTION/METHODS: ID and GI were consulted who recommended initiation of azithromycin, rifabutin, and ethambutol given the high suspicion for disseminated Mycobacterium avium complex (MAC). After 12 days of hospitalization, her diarrhea had not improved, and the decision was made to perform EGD and colonoscopy. EGD demonstrated atrophic mucosa in the 2nd and 3rd portions of duodenum. Colonoscopy showed severe colitis in the ileocecal valve. The TI had multiple erythematous, hypervascular appearing lesions with the appearance of angioectasias. The pathology of the duodenal, terminal ileum, IC valve, and random colon biopsies all showed acid-fast bacilli bacteria within the macrophages. Given the endoscopy findings with blood cultures which were previously positive and eventually grew MAC, the diagnosis of disseminated MAC was confirmed. Her diarrhea gradually improved and she was restarted on HAART before discharge. DISCUSSION: In the post-HAART era, the incidence of diarrhea attributed to opportunistic infections has decreased1; however, the workup and evaluation for infectious diarrhea continues to be paramount. The American Society for Gastrointestinal Endoscopy recommends stool testing for pathogens as the first-line evaluation followed by endoscopy when the diarrheal illness is persistent and stool tests fail to reveal a cause in immunocompromised patients2. MAC can affect several parts of the gastrointestinal system. In one review of previously reported cases of MAC with GI involvement, endoscopy demonstrated involvement of the duodenum (76%), rectum (24%), ileum (6%), colon (4%), esophagus (4%), and jejunum (2%)3. MAC colonization of the gastrointestinal tract is important because it increases the risk of disseminated MAC with the risk of MAC bacteremia approaching 60% with in 1 year4. Our approach to this patient was to perform endoscopy only when her symptoms persisted despite treatment. This case was interesting in that duodenum, ileum, and colon were all affected. Lastly, this case was an excellent example of several classic MAC findings.