A 58-year-old man with progressive dyspnea suffering from Munier-Kuhn syndrome

Abstract

A 58-year-old man who was a former smoker and had a 20-pack-year smoking history presented to the hospital with worsening shortness of breath. Pulmonary function tests revealed mixed obstructive-restrictive physiology. Forced vital capacity (FVC) was predicted at 68%, forced expiratory volume in 1 second (FEV1) at 60% was predicted, FEV1/FVC at 67% was predicted, and Carbon monoxide (DLCO) diffusion capacity is expected to be 70%. Chest images show increased interstitial density around the hilum. There is massive tracheobronchiomegaly with a tortuous appearance in the airways. There is also a small degree of parenchymal scarring and fibrosis-like reticular perihilar interstitial opacity. CT images show traction bronchiectasis is a finding in the setting of fibrotic lung disease. When lung tissue becomes inelastic due to the formation of dense fibrosis, the airways appear blocked and dilated. Although this patient has dilated airways, the bronchiectasis is greater than the small amount of parenchymal fibrosis seen. Therefore, this process is not caused by parenchymal fibrosis, but rather by inherent pathology of the airway wall. The most frequently reported symptoms of Mounier-Kuhn syndrome are severe cough, difficulty breathing, and recurrent respiratory infections. Patients may complain of chest pain and hemoptysis, but systemic symptoms are rare and require immediate investigation for other diseases. Pulmonary function tests often reveal obstructive pulmonary disease, but in advanced stages there may be limited parenchymal changes, resulting in a mixed appearance, as in a patient's case. Because airway changes are considered irreversible, treatment is aimed at managing symptoms and reducing long-term complications. Recommended lifestyle modifications include quitting smoking and avoiding irritants/particulates. Concurrent COPD or asthma is addressed to limit further morbidity. The infection is treated aggressively, usually requiring broad-spectrum antibiotics to treat atypical infections. The use of expectorants and chest physiotherapy is considered helpful in preventing recurrent infections. Tracheal stenting may be considered if there are specific airways prone to collapse, but the spread of airway involvement limits its potential utility.