Fungitell Tells It All: A Case of Pneumocystis Jirovecii Pneumonia

ABSTRACT

Introduction: The Fungitell assay is an in vitro diagnostic test for the qualitative detection of (1-3)-beta-D-Glucan (BDG) in serum. It can be particularly useful in early diagnosis of fungal infections that would otherwise take weeks to finalize in culture.DescriptionThis is a case of a 73 year old Filipino female with a history of diffuse large B-cell lymphoma status post RCHOP therapy, currently maintained on Ritixumab, and rheumatoid arthritis treated with Methotrexate who was admitted to the hospital with increasing shortness of breath for several weeks. In the Emergency Department she was hypoxic and required 2 liters of oxygen via nasal cannula and with 92% oxygen saturation. Her vital signs were otherwise normal. She was afebrile and WBC was 9.4. She had a negative respiratory viral PCR which included COVID-19. Infectious work up including sputum culture and urine antigens were also sent. A CT chest was performed and showed bilateral ground glass opacities suspicious for atypical pneumonia.There was concern for drug toxicity from Methotrexate which was subsequently suspended. A bronchoscopy and bronchoalveolar lavage (BAL) was performed to rule out infection prior to starting steroids for suspected pneumonitis. Cell count from the BAL revealed low neutrophils. There was negative growth over the next 48 hours. Steroids were initiated at 1 mg/kg daily and patient was discharged home with close outpatient follow up scheduled. A fungitell (serum beta D glucan) that was collected from the BAL had resulted after the patient was discharged home. The level returned very elevated (>500). The patient was contacted and she reported that her symptoms did not improve with the steroids. She was still requiring up to four liters of oxygen at home. She was asked to return to the hospital to work up an undiagnosed fungal or PJP pneumonia. A repeat bronchoscopy was performed and a PJP PCR was tested on the BAL. This returned positive. She was started on Bactrim for 14 days to treat PJP pneumonia. She was weaned down to 2 liters of oxygen and was doing well from a pulmonary standpoint at her outpatient follow up visit 2 weeks later. Discussion: The Fungitell assay test in this case was crucial to help guide us to the correct diagnosis. In patients who are immunocompromised, physicians should utilize specialty testing such as Fungitell when it is available. Compared to microbial fungal culture, Fungitell results faster, has a higher sensitivity and a higher negative predictive value. (Figure Presented).