Invasive Fungus Balls Diagnosed by Point-of-Care Ultrasound in the Emergency Department.

Background: Genitourinary tract fungus balls are a rare complication of urinary tract infections (UTI). They arise from dense aggregations of hyphae that combine with surrounding urothelial cells and debris. Symptoms can progress to urosepsis and systemic dissemination. Unfortunately, fungus balls may remain unrecognized. Even with computed tomography (CT) and magnetic resonance imaging, fungus balls can be mistaken for malignancies, urinary calculi, or blood clots.

Case Report: A 54-year-old man with past medical history of type 2 diabetes mellitus presented to the Emergency Department (ED) reporting urinary retention for one week. He had undergone Foley catheter insertion three separate times for this symptom over the past five weeks. The emergency physicians expected that point-of-care ultrasound (POCUS) would show a distended, anechoic bladder. Instead, there were multiple discrete, gravitationally-dependent, circular echogenic masses without posterior acoustic shadowing, floating freely within a mosaic-like background of mixed echogenicity urine. These findings, together with the CT scan subsequently ordered, raised concern for fungus balls. Instead of being discharged with antibiotics for UTI, the patient was admitted for antifungal coverage, with contingency plans for bladder irrigation and antifungal instillation as needed. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This is the first known case report in which emergency physicians used POCUS to diagnose invasive fungus balls in the ED. POCUS findings led to further CT imaging and specialist consultation that otherwise would not have occurred. Rather than discharge with antibiotics, goal-directed management and appropriate disposition mitigated the risk of systemic decompensation in an immunocompromised patient.