S5104 Mycobacterium avium Complex Peritonitis in a Geriatric Patient With Multiple Myeloma: A Rare and Lethal Complication of Peritoneal Dialysis

Introduction: Peritoneal dialysis-associated mycobacterium avium complex (MAC) peritonitis is extremely rare, with only 10 cases reported to date. Due to its rarity, optimal treatment guidelines are still lacking. The slow growth of the organism and its vague clinical presentation often lead to a delay in diagnosis. Herein, we describe an exceedingly rare case of peritoneal dialysis-related MAC peritonitis in a geriatric patient with multiple myeloma and on chemotherapy. Prompt diagnosis and treatment are crucial but challenging given the non-specific nature of the symptoms of MAC peritonitis. Case Description/Methods: An 85-year-old woman with a history of multiple myeloma on chemotherapy and ESRD on peritoneal dialysis (PD) was readmitted for vomiting and diffuse abdominal pain. The patient was admitted to our hospital 5 weeks prior for similar symptoms and treated for secondary bacterial peritonitis. At the time, she had cloudy ascitic fluid, erythema at the catheter insertion site, and fluid cultures were positive for Corynebacterium species. She required a prolonged course of intraperitoneal and intravenous vancomycin and cefepime. On readmission, a focused exam revealed diffuse abdominal tenderness without peritonism or signs of infection at the catheter exit site. Labs: BUN 29 mg/dL, creatinine 6.43 mg/dL, and white blood cell 13.5 × 103/mm3. AFB cultures obtained during the previous admission returned positive. The patient was placed on airborne precautions and started on rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) therapy. The chest computed tomography (CT) scan was negative for focal consolidations. The culture sensitivities returned positive for MAC and the treatment regimen was narrowed down to ethambutol, rifampin, and azithromycin. The PD catheter was removed, and the patient was transitioned to hemodialysis with a TDC. The patient has completed a 6-month course of MAC peritonitis therapy and remains asymptomatic. Discussion: Even though improvements in PD techniques and technology have led to a decrease in the incidence of PD-associated peritonitis, it remains a challenge in health care due to higher mortality, increased healthcare utilization, and cost. Peritonitis due to atypical infectious organisms, such as MAC is very rare and a diagnostic challenge. These pathogens should be highly suspected in patients with culture-negative peritonitis, refractory peritonitis, previous MAC infection, or a cloudy dialysate. In PD patients, the dialysis effluent should be removed, inspected, and sent for microbiological analysis.