Interval Development of Multiple Sub-Segmental Pulmonary Embolism in Mycoplasma Pneumoniae Bronchiolitis and Pneumonia

Introduction: Cases of pulmonary embolism (PE) concurrent with Mycoplasma pneumoniae infection are rare in the medical literature. We describe a patient with M. pneumoniae bronchiolitis and pneumonia who developed multiple right-sided, subsegmental PE. Case Description: A 54-year-old man presented following one week of respiratory and constitutional symptoms. He was admitted for respiratory distress and started on ceftriaxone, azithromycin, and oseltamivir. Because of a lack of clinical improvement, antibiotics were escalated to vancomycin and piperacillin-tazobactam. M. pneumoniae IgM and IgG serologies returned positive, and antibiotics were narrowed to azithromycin, with clinical improvement and gradual decrease in supplemental oxygen requirement. One week into the hospitalization, the patient abruptly developed an increased oxygen requirement. Computed tomography angiography (CTA) of the chest found stable M. pneumoniae bronchiolitis and pneumonia and the interval development of multiple right-sided, sub-segmental PE. He was treated with unfractionated and then low-molecular-weight heparin as a bridge to warfarin, azithromycin, and a prednisone taper. In the outpatient setting, repeat CTA revealed resolution of M. pneumoniae infection and PE. Discussion: Although the mechanism and association are unclear, other case reports have proposed that M. pneumoniae infection promotes hypercoagulability or a prothrombotic state, predisposing patients to thromboembolism. In a patient with M. pneumoniae infection who develops sudden respiratory distress or failure despite appropriate treatment, clinicians should have a high suspicion for PE, and a CTA should be considered as part of further evaluation.