Case Presentation: 31-year-old man presented with two-weeks of shortness of breath to a New York City hospital in late-April 2020. Patient reported subjective fevers/chills and myalgias two weeks prior to presentation, eventually progressing to shortness of breath and a dry, non-productive cough. In the emergency department, he was noted to be in respiratory distress, saturating 82% on room-air, respiratory rate of 26, and heart rate of 137. Labs notable for lymphopenia, high lactate dehydrogenase (LDH), and high C-Reactive protein. Chest X-ray showed bilateral airspace opacities, consistent with multifocal pneumonia. Nasal PCR for the SARS-CoV-2 virus was negative, but given the high prevalence of the virus, this was considered a false negative. Due to persistent hypoxia and elevated inflammatory markers, a five-day Prednisone course was started. Although he subsequently initially improved, patient’s supplemental oxygen requirements increased once his Prednisone was completed. CT chest showed extensive ground-glass opacities without evidence of pulmonary embolism. On further questioning, he admitted to a 30 pound weight loss, and further work-up revealed HIV positivity, CD4 count of 6 cells/uL, and Beta-D glucan of >500pg/mL. Patient was diagnosed with Pneumocystis Jirovecii Pneumonia (PJP) and improved with prednisone and sulfamethoxazole-trimethoprim.
Discussion: PJP can be a cause of pneumonia in severely immunocompromised individuals. The most common symptoms are non-specific, including shortness of breath, fever and dry cough. Nearly all patients will have hypoxemia. Imaging findings are variable, but frequently show diffuse interstitial infiltrates on radiograph and extensive ground-glass opacities on computed tomography. Such findings are also commonly seen in COVID-19 Pneumonia, making it difficult to distinguish between the two without a high index of suspicion. However, a presumptive diagnosis of PJP can be made if a patient has consistent imaging findings, risk factors, and an elevated beta-D glucan. Beta-D glucan has good sensitivity and high negative predictive value in those with HIV, and the specificity approaches 100% when Beta-D glucan is > 200 pg/mL. Definitive diagnosis of PJP can be made with tinctorial or fluorescent antibody staining or PCR-based assays of respiratory sputum. Treatment is based on the degree of respiratory failure and those with severe disease, defined as a PaO2 less than 60, should be started on intravenous sulfamethoxazole-trimethoprim and corticosteroids.
Conclusions: Even in the COVID-19 era, it is important to avoid anchoring bias and re-evaluate patients who are persistently hypoxic with diffuse infiltrates on imaging for alternative, treatable causes, such as PJP.