DISSEMINATED MAC IN A YOUNG IMMUNOCOMPETENT PATIENT

Abstract

SESSION TITLE: Monday Medical Student/Resident Case Report Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/21/2019 02:30 PM - 03:15 PM INTRODUCTION: Disseminated MAC (dMAC) is a disease usually seen in HIV infected patients with a CD4 count less than 50 cells/microL. In immunocompetent hosts, the usual presentation is of an isolated pulmonary infection, that usually presents as upper lobe lesions resembling mycobacterium tuberculosis. It has also been described to present as solitary pulmonary nodule, but virtually all the cases were older females. We describe a case of a young immunocompetent 31 years old female with no known risk factors presenting with dMAC. CASE PRESENTATION: A 31 years old female with type 1 diabetes presented with nausea, vomiting, diarrhea, abdominal pain and a high anion gap suggestive of DKA. DKA resolved with IV fluid resuscitation and insulin drip, but the patient was noted to have high grade fevers that did not resolve with empiric broad spectrum antibiotics. On further questioning, she reported a 13 pound weight loss in the last 2 months. Multiple sets of blood cultures obtained were negative. CT scan imaging of chest abdomen & pelvis noted ground glass opacities in bilateral lower lobes with superimposed multiple pulmonary nodules & infiltration of the mesenteric fat without lymphadenopathy or hepatosplenomegaly. Patient underwent cholecystectomy after a HIDA scan showed acute cholecystitis as a possible source of sepsis syndrome. She was also noted during her admission to have pancytopenia with elevated LFTS which prompted a bone marrow biopsy to be done. Repeat CT scan chest demonstrated a new right upper lobe consolidation, an increase in the size of the pulmonary nodules and new splenomegaly. Patient underwent bronchoscopy with BAL for fungal and bacterial cultures. Patient was diagnosed with dMAC infection after her gallbladder, bone marrow biopsy and her BAL grew Mycobacterium Avium Intracellular. She was started on azithromycin, ethambutol, rifapentine and amikacin with significant improvement. DISCUSSION: The usual presentation of Disseminated MAC is with persistent fevers (>80%), weight loss (>25%) & non- specific symptoms such as fatigue, anorexia. Organs such as bone marrow, lung, lymphoreticular and gastrointestinal tract can be involved. Diagnosis is made by peripheral blood cultures, but care should be taken to order mycobacterial blood cultures to hasten the diagnosis and spare the patient invasive procedures. Susceptibility testing should be done as macrolide resistant isolates have been identified. Macrolide susceptible MAC treatment consists of a macrolide plus ethambutol plus a rifamycin. Amikacin can be added during the initial treatment course if the disease is life threatening. The duration of treatment is at least 6 months. CONCLUSIONS: High clinical suspicion is required to diagnose disseminated MAC with multi-organ involvement in immunocompetent hosts. Mycobaterial blood culture should be ordered and is the least invasive test to diagnose this possible life threatening disease. Reference #1: Teirstein AS, Damsker B, Kirschner PA, et al. Pulmonary infection with Mycobacterium avium-intracellulare: diagnosis, clinical patterns, treatment. Mt Sinai J Med 1990; 57:209. Reference #2: Nightingale SD, Byrd LT, Southern PM, et al. Incidence of Mycobacterium avium-intracellulare complex bacteremia in human immunodeficiency virus-positive patients. J Infect Dis 1992; 165:1082. Reference #3: Yabes JM, Farmer A, Vento T. Disseminated Mycobacterium avium complex in an immunocompetent host. Int J Mycobacteriol 2017;6:202-6 DISCLOSURES: No relevant relationships by Wafic Itani, source=Web Response no disclosure on file for Thomas Smith; No relevant relationships by Ali Wazir, source=Web Response