A Case of Pulmonary Cryptococcosis After Severe COVID-19 Pneumonia

Abstract

Introduction / Case Presentation:46yo female with a history of CKD, atrial flutter, bioprosthetic valve with mitral ring, and recent COVID-19 pneumonia who presented to the emergency department (ED) with shortness of breath, fevers, and fatigue. Three months prior, she had been diagnosed with severe COVID-19 pneumonia, for which she received dexamethasone, remdesivir, tocilizumab, anakinra, and IVIG. She was discharged to a nursing facility with a prolonged steroid taper, ending 1 month prior to admission.In the ED, the patient had a chest x-ray that demonstrated bibasilar atelectasis and opacification, and a CT chest revealed right lower lobe consolidation and surrounding ground glass opacities. A respiratory pathogen PCR swab was negative. Sputum culture was negative for bacterial and fungal growth. Blood cultures did not grow any organisms. Given recent immunosuppression and imaging findings, a serum Cryptococcal antigen was drawn, which was positive with a titer of 1:128. A transthoracic needle biopsy of the patient's right lower lung was then performed. The specimen did not grow any bacteria or fungi and AFB stain on the tissue was negative. Pathology demonstrated a collection of histiocytes, neutrophils, and necrotic debris. PAS, GMS, and mucicarmine stains were positive for fungal organisms consistent with Cryptococcus species. Discussion: Cryptococcosis is a fungal infection due predominately to one of two encapsulated yeasts, Cryptococcus neoformans or Cryptococcus gattii. C. neoformans is found in soil worldwide, and infection typically begins with spore inhalation. Clinically significant disease is seen mostly in immunocompromised patients.Corticosteroids and interleukin inhibitors, such as anakinra (IL-1) and tocilizumab (IL-6), are used in the treatment of COVID-19. These medications have been associated with increased risk for opportunistic infections, including invasive fungal infections. The diagnosis of pulmonary cryptococcosis may be challenging, as symptoms are often nonspecific and may radiographically resemble bacterial pneumonia, malignancy, or other infections. Serum cryptococcal antigen detection tests may be helpful in establishing the diagnosis, as well as histopathology showing narrow-based budding yeast. Conclusion: Patients with prior COVID-19 infection commonly return to healthcare settings with sequelae of their previous coronavirus infection. In our case, it was the prior treatment of COVID-19, which included immunomodulating therapy, that lead to a secondary pulmonary cryptococcal infection. When evaluating pulmonary processes that evolve after an acute infection with COVID-19, it is important to keep a broad differential, including uncommon and/or opportunistic infectious etiologies, particularly when a patient has received prolonged courses of steroids and tocilizumab.