IS Case 347: Mounier-Kuhn syndrome
2009 URMC Imaging Sciences
Publication Date: 2009-11-09
Findings are consistent with Mounier-Kuhn disease.
Figures 1-4: Axial and coronal high resolution CT images of the upper chest shows enlarged tracheal diameter measuring 3 cm with apical emphysematous changes (Fig. 1), scalloping of the tracheal wall (arrow on Fig. 2), and extensive basilar bronchiectasis (arrows and arrowheads on Figs. 3 & 4).
Mounier-Kuhn or tracheobronchomegaly is an autosomal recessive abnormality that results in dilation of the tracheobronchial tree. It is more common in males and African Americans. The disease usually presents in the third or fourth decade of life. Symptoms include dyspnea, cough, hoarseness, purulent sputum production, and recurrent pneumonia.
Mounier-Kuhn is primarily diagnosed by CT. The main finding is tracheobronchomegaly, with tracheal, left mainstem, or right mainstem bronchi diameters measuring greater than 3.0, 2.0, or 1.8 cm respectively. Secondary findings usually result from the associated chronic infections and include bronchiectasis, bulla formation, and pulmonary fibrosis. Dynamic studies can show the trachea and major bronchi distend with inspiration and collapse during expiration. Complete occlusion can occur during coughing. Loss of elastic fibers, smooth muscle thinning with sacculation, and diverticular formation between cartilage rings are seen pathologically. Radiographically, this manifests as scalloping or diverticula formation involving the tracheal wall.
Differential diagnosis includes tracheobronchomegaly associated with Ehlers-Danlos and other connective tissue disorders, cystic fibrosis, diseases with chronic infections such as ataxia telangiectasia and Bruton’s agammaglobulinemia, and tracheomalacia from chronic obstructive pulmonary disease (COPD) or relapsing polychondritis.
The prognosis is variable as Mounier-Kuhn can range from minimal disease with good pulmonary function to severe disease resulting in respiratory failure and death. Treatment is supportive with antibiotics, secretion moderation, and smoking cessation. Stenting can be used with severe tracheal collapse.
- Lazzarini-de-Oliveira LC, Costa de Barros Franco CA, Gomes de Salles CL, de Oliveira AC Jr. A 38-year-old man with tracheomegaly, tracheal diverticulosis, and bronchiectasis. Chest. 2001 Sep;120(3):1018-20.PMID: 11555541
- Webb EM, Elicker BM, Webb WR. Using CT to diagnose nonneoplastic tracheal abnormalities: appearance of the tracheal wall. AJR Am J Roentgenol. 2000 May;174(5):1315-21. PMID: 10789785