A rare case of diffuse alveolar hemorrhage caused by acute mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae is a common bacterial pathogen that causes atypical community-acquired pneumonia. Illness onset can be gradual and progressive over weeks. Patients typically have cough, pharyngitis, malaise, and tracheobronchitis. Although symptoms are frequently mild, the initial presentation can be severe with numerous complications. We present a case of a 28-year-old male who presented with 1 day of significant hemoptysis. He was intubated for airway protection and underwent bronchoscopy, which showed multiple blood clots in several lung lobes, consistent with diffuse alveolar hemorrhage (DAH). His workup was negative for pulmonary embolism, coagulopathy, and vasculitis. He tested positive for rhinovirus and mycoplasma pneumoniae IgM (negative IgG). He was ultimately discharged home with oral doxycycline to complete a 10-day course. DAH is a rare presentation and life-threatening complication of mycoplasma pneumonia. Although there is a reported association between DAH and rhinovirus, our patient improved with antibiotics making mycoplasma pneumoniae the likely culprit. When encountering hemoptysis or alveolar bleeding, clinicians should have low suspicion for atypical infections and start appropriate antibiotics early in the clinical course.