Differential Diagnosis, Investigations, and Treatment
Given these findings, empiric antibiotic treatment was started for suspected brain abscess, but as metastatic disease could not be ruled out, brain and transbronchial biopsies were performed. Histopathologic examination revealed a brain abscess with both budding yeast and filamentous bacilli (Figure 1), and cultures of the brain biopsy grewR. mucilaginosa and N. abscessus . Lung biopsy was unremarkable. Due to the rare, invasive fungal infection in the absence of known risk factors such as CVC, work-up for immunocompromising conditions was undertaken, eventually revealing a diagnosis of CVID. Empiric antibiotic therapy was thus replaced with meropenem, trimethoprim-sulfamethoxazole, and liposomal amphotericin B. Amphotericin B associated electrolyte abnormalities prompted a switch to voriconazole, but unfortunately, despite several weeks of intensive medical therapy, the patient’s respiratory status continued to decline and she was transferred to the ICU for mechanical ventilation.