Siblings in the ICU: Keeping Endemic Mycoses on the Differential

Blastomycosis is a rare fungal infection caused by the inhalation of <i>Blastomyces dermatitidis</i> spores. Infection with this fungus can impact nearly every organ system, though pulmonary disease is the most common. Presentations of pulmonary blastomycosis are highly variable, ranging from clinically asymptomatic to severe respiratory failure requiring intensive care. This case series describes the clinical presentation, diagnostic challenges, management, and outcomes of two siblings with severe pulmonary blastomycosis that progressed to pediatric acute respiratory distress syndrome requiring mechanical ventilation and venovenous extracorporeal membrane oxygenation (VV-ECMO). Despite being relatively uncommon, blastomycosis should be considered in patients with respiratory symptoms not responding to empiric antibacterial therapy, particularly in endemic regions. Early diagnosis and prompt initiation of appropriate antifungal therapy are crucial for favorable outcomes. Additionally, early initiation of ECMO for severe pulmonary blastomycosis may be beneficial in temporizing to allow time for sufficient response to antifungal therapy.