First endogenous case of <i>Blastomyces dermatitidis</i> ARDS in an immunocompetent man in Newfoundland and Labrador: Case report and mini-review

Background: Blastomycosis is a fungal infection that can be localized to the lungs or disseminated to the skin, bone, and the central nervous system. Blastomycosis is endemic in parts of North America, specifically the Great Lakes region; the endemicity of the pathogen is a crucial diagnostic clue. Case Presentation: An adult immunocompetent man with no travel history outside of Newfoundland presented to a community centre with respiratory symptoms and several months of constitutional symptoms. He had several new papulo-ulcerated skin lesions and a single mucosal ulcer on the dorsal posterior tongue. Initial septic workup was negative. He was initially treated with empiric piperacillin-tazobactam, azithromycin, and vancomycin. His condition progressed to respiratory failure in keeping with acute respiratory distress syndrome (ARDS), necessitating intubation and mechanical ventilation. A bronchoalveolar lavage specimen submitted to the microbiology laboratory just prior to withdrawal of care showed budding yeast; the patient died before treatment could be initiated. An autopsy was performed, which demonstrated fungal pneumonia, confirmed as Blastomyces on polymerase chain reaction testing of formalin-fixed lung tissue. Discussion: This case represents a probable shift in the Canadian epidemiology pattern of blastomycosis, as this is the first reported endogenous case in the province. Given this, clinicians should consider blastomycosis in their differential beyond the Great Lakes region, especially when no other etiology of ARDS has been found. This case represented numerous diagnostic challenges, especially in distinguishing various dimorphic fungi on histopathology. A mini-review of morphologically related fungi of clinical importance in North America is included.