A Rare Presentation of a Rare Case: Acute Respiratory Failure in Swyer-James-Macleod Syndrome.

Swyer-James-Macleod syndrome (SJMS) is a rare clinical entity acquired during childhood due to a respiratory infection leading to bronchiolitis obliterans. This inciting event is hypothesized to cause structural and functional changes of the developing alveoli, terminal bronchioles, and the corresponding pulmonary vasculature, resulting in emphysematous changes and a matched ventilation-perfusion defect. We present a 67-year-old male patient with hypercapnic respiratory failure requiring invasive mechanical ventilation, who had typical features of SJMS undiagnosed before this admission. He was extubated successfully, discharged home, and continues to be stable at a 90-day follow-up period. This marks one of the rare accounts where a patient with SJMS was given ventilatory support emergently, and one of the oldest patients reported. SJMS is under-reported due to its indolent clinical course and misdiagnosed as some other pulmonary abnormality. The clinical course progression and prognosis are unclear and variable in many affected patients due to this condition's rarity.