Case Presentation: A 29-year-old male with a history of Crohn’s Disease controlled on Humira presented with two weeks of fever and fatigue. His review of systems was notable for mild left flank pain and nasal congestion. Blood work revealed a white blood cell count of 14.3 (76% neutrophils) and a CRP of 171.2. Initial infectious workup, including urine and blood cultures as well as a chest X-ray, did not identify a source of fever. A CT scan of the abdomen and pelvis demonstrated heterogeneous enhancement of the upper pole of the left kidney, suggestive of focal pyelonephritis, along with a small 8 mm cystic lesion, potentially an early renal abscess (Fig. 1). Empiric treatment with Vancomycin and Zosyn was initiated for presumed pyelonephritis, but the patient continued to have fevers. Antibiotics were broadened to meropenem without resolution, and inflammatory markers (WBC and CRP) remained elevated. Fungal markers, including Beta-D-glucan, urine histoplasma antigen, and galactomannan antigen, were all negative. A renal biopsy of the affected area revealed extensive necrotizing and non-necrotizing granulomatous inflammation, but cultures and AFB stains were negative. Renal involvement due to Crohn’s Disease was considered, though deemed unusual given the patient’s well-controlled disease. Subsequently, fungal PCR from the biopsy returned positive for aspergillosis. The patient was started on voriconazole, leading to clinical improvement and interval improvement on repeat CT imaging.
Discussion: Aspergillosis is caused by inhaled fungal spores, typically infecting the lungs but capable of disseminating to other organs, including the skin, eyes, liver, and kidneys. Diagnosis is challenging due to the low sensitivity of cultures (25–50%) and serum markers, such as galactomannan antigen (30–80% sensitivity). Based on a systemic review of cases on aspergillosis involving the genitourinary system, 81.3% percent had isolated renal infections. Most were reported in males with a median age of 46 years. Most cases improved on antifungal therapy, but approximately 20% required nephrectomy.
Conclusions: Extra-pulmonary aspergillosis is seen in immune compromised patients. Isolated renal aspergillosis is uncommon but carries high mortality of approximately 25%. Because cultures and serum studies do not have high sensitivity, it can be a diagnostic challenge. It’s important to consider as a differential in immune compromised patients to ensure early detection and treatment.
