Diffuse Alveolar Hemorrhage Secondary to Human Metapneumovirus Pulmonary Infection

A 67-year-old man presented with a week of flu-like symptoms, hypoxia, and fever. Respiratory viral panel was positive for human metapneumovirus. Initial chest imaging showed left lower lobe opacification, suggesting a bacterial superimposed on viral pneumonia. Despite antibiotics, the patient became tachycardic and increasingly hypoxic, requiring 40 L high-flow nasal cannula. Repeat imaging demonstrated worsening of a left lower lobe process. Elective bronchoscopy with bronchoalveolar lavage revealed hemorrhage. Subsequent autoimmune, bacterial, and fungal workup was negative. The patient was diagnosed with diffuse alveolar hemorrhage (DAH) secondary to human metapneumovirus pneumonia. DAH is defined as bleeding into the alveolar spaces of the lungs, a process which carries high rates of morbidity and mortality.1 While dramatic in name and often associated with hemoptysis, DAH may only present with clinically subtle and nonspecific features with a variety of alternative etiologies to consider. We present this case of DAH secondary to human metapneumovirus (hMPV) to promote discussion of etiologies of DAH aside from systemic vasculitis.