BACKGROUND: Many conditions and triggers have been identified and associated with spontaneous pneumomediastinum (SPM), including asthma, strenuous exercise, chronic obstructive pulmonary disease, diabetic ketoacidosis, inhalational drugs, and other activities associated with the Valsalva maneuver. Among rare findings reported in patients with SPM is tracheal diverticulum. We present a case of SPM that on further evaluation was noted to have a tracheal diverticulum, together with a possible diagnosis of asthma.

CASE REPORT: A 25-year-old male was admitted to the hospital for dyspnea and chest pain. Based on initial assessment, laboratory findings, and imaging, he was diagnosed with SPM. Recovery was successful, and the patient was discharged 3 days later. Follow-up at 2 weeks revealed an abnormality on imaging and abnormal pulmonary function tests. A computed tomography scan revealed a tracheal diverticulum located on the right posterolateral region of the trachea at T1 level. Pulmonary function tests abnormalities included: high fractional exhaled nitric oxide (FeNO), high lung clearance index (LCI), and elevated diffusing capacity of the lungs for carbon monoxide (DLCO).

CONCLUSIONS: Although the patient presented with a normal spirometry, the FeNO, LCI, and DLCO findings proved valuable and suggested a possible diagnosis of asthma. The anatomic weakness associated with the tracheal diverticulum could have been the breaking point of sustained increased pressure in the airways, due to a possible asthma exacerbation. In retrospective, we hypothesized this to be a series of events that ultimately ended as a pneumomediastinum.

Keywords: Asthma, Pneumomediastinum, Diagnostic, Respiratory Function Tests, Tracheal Diseases