Clinical History
A 52-year-old woman presented with cough and bloody sputum.
Imaging Findings
A 52-year-old woman presented to our emergency department with cough and bloody sputum. She denied of having fever, chest pain, dyspnea or weight loss. Her expectoration was declining gradually. The
patient had a 150 pack-year history of tobacco use several years ago and also had multiple prior episodes of pneumonia, sometimes with bloody sputum. A physical examination done revealed a
well-nourished patient. The results of blood analysis were within normal limits. A chest radiograph (Fig. 1) and a helical CT scan (Fig. 2) were performed, which showed tracheomegaly with a
transversal diameter of 30 mm. Many diverticular outpouchings were present from membranous parts of the trachea. Dilatation of central airways and cystic bronchiectasis involving both lower lobes
were additional findings.
Discussion
Mounier-Kuhn syndrome is a rare disorder characterized by a marked dilatation of the trachea and main bronchi, sometimes with diverticulosis (1/3 patients), bronchiectasis, and recurrent lower
respiratory tract infections (1). The airways distal to the fourth-order and fifth-order division are usually normal in diameter. The etiology of this syndrome remains unknown. Autopsy studies
suggest a congenital defect or atrophy of the internal elastic membrane and smooth muscle tissue of the trachea and main bronchi, which results in dilatation of the cartilaginous skeleton and
external protrusion of the intercartilaginous parts of the tracheal wall, inducing diverticula (2). Flaccidity of the trachea and main bronchi results in a marked dilatation on inspiration, with
narrowing or collapse on expiration. Although the majority of cases appear to be sporadic, a familial form has been described. Secondary tracheobronchomegaly was also described in association with
Ehlers-Danlos syndrome, Marfan syndrome, cutis laxa in children, Kenney-Caffe syndrome, and connective tissues diseases (3). The symptoms of this entity are non-specific, with sputum production
secondary to bronchiectasis and lower respiratory tract infection. Almost 50% of the patients show no symptoms until the third decade of life (4). The dilatation of the trachea and the main bronchi
is visible on the chest radiograph. A tracheal diameter superior to 25 mm in men and 21 mm in women on a posteroanterior view is required for the diagnosis (5). Tracheal diverticulosis may result in
an irregular corrugated or scalloped appearance of the trachea and, occasionally, the main bronchi, which is best seen in the lateral view. Tracheal changes are well appreciated on a CT scan. The
treatment is limited to physiotherapy to assist in clearing secretions and adequate antibiotics during infectious episodes.
Differential Diagnosis List
