A 53-year-old man presented to the hospital after gaining weight for 6 months and had developed peripheral edema and abdominal distension. He also had HIV for 32 years, had undergone a renal cadaveric transplant 2 years earlier, and had type 2 diabetes, coronary artery disease, and dyslipidemia. The patient was taking > 10 medications, including immunosuppressants and antiretrovirals.
Based on the physical examination and abdominal ultrasonography, the clinicians diagnosed the patient with ascites but could not confirm the cause. Although nonhepatic causes account for only about 15% of all ascites cases, the differential diagnosis includes malignant disease, lymphatic obstruction, and infections. But samples of ascitic fluid were negative for malignant disease and mycobacteria, and there was no evidence of lymphadenopathy. Lacking a definitive diagnosis, the clinicians decided on watchful waiting, with large-volume paracentesis every 2 to 3 weeks.
However, the patient returned to the hospital 1 week later with shortness of breath, nonproductive cough, and fever. Computed tomography (CT) scan showed small pleural effusions and consolidation in the lower lung. This time, a mycobacterial culture was positive for Mycobacterium avium (M avium ) complex.
Antimycobacterial drugs were added to his regimen, and his symptoms rapidly resolved. A CT scan confirmed improvement. Six months later, he was doing well, without recurrence.
The clinicians note that their patient was at increased risk because of the double toll HIV infection and the transplant had taken on his immune system. But the diagnosis was challenging because contrary to the school of thought that M avium complex infections are usually seen with CD4 count < 50 cells/µL, their patient’s count was 141 cells/µL at diagnosis.
When mycobacterial infections are suspected, patients may need extensive testing and close monitoring before the diagnosis can be made, the clinicians say. They suggest counseling patients about the potential need for invasive testing and the risks of possible diagnostic delay. Wherever possible, the clinicians add, patients with M avium complex should be overseen by infectious disease specialists and pharmacists to reduce the risk of harmful drug-drug interactions.
Auguste BL, Patel AD, Siemieniuk RA. CMAJ. 2018;190:E394-E387.