Diagnosis of the case presented in the previous edition

RADIOLOGICAL DIAGNOSIS

Diagnosis of the case presented in the previous edition

Mounier-Kuhn Syndrome

56 year-old male

Chronic cough and repeat infections

Mounier-Kuhn syndrome, also known as tracheobronchomegaly, is a rare disease, characterized by dilatation of the trachea and main bronchi. The disease may be accompanied by tracheal diverticulosis, bronchiectasis and recurrent infections of the upper respiratory tract.

Its etiology remains unknown. Analysis of biopsy and autopsy samples has shown that elastic and muscle fibers are atrophied, few or absent in the trachea and main bronchi. As a result, the tracheal mucosa may become herniated through the cartilaginous rings, creating abnormal outpouchings. In addition, enlargement and flaccidity of the tracheobronchial walls generate an inefficient cough mechanism, impeding proper mucociliary clearance. This, together with the accumulation of secretion in the tracheal outpouchings, favors the establishment of recurrent pneumonia, emphysema and bronchiectasis. Some cases of Mounier-Kuhn syndrome have been attributed to diffuse pulmonary fibrosis, mechanical ventilation (in neonates) and repeat infections of the lower airways. However, the majority of cases are idiopathic in origin. The syndrome is slightly more common among black men in their 30s or 40s.

It is difficult to differentiate chronic bronchitis or bronchiectasis from Mounier-Kuhn syndrome because its symptoms are nonspecific: productive cough (with or without hemoptysis) and progressive dyspnea that can lead to respiratory insufficiency. Complications, such as pneumonia, spontaneous pneumothorax or massive hemoptysis, may occur.

Diagnosis is made through imaging techniques. In radiological images, a tracheal diameter greater than 30 mm and main bronchi diameters greater than 24 mm and 23 mm on the right and left, respectively, are diagnostic of the syndrome. In computed tomography (CT) images, these same diagnostic values are 30 mm, 20 mm and 18 mm, respectively. Findings such as protrusion of musculomembranous tissue from between the cartilaginous rings, tracheal diverticulosis (outpouchings) can aid in making the diagnosis since they are present in one-third of all cases. In general, the bronchi become dilated up to the fourth segment, assuming the normal caliber thereafter. Such measurements are best taken with high-resolution CT scans. In dynamic CT imaging, tracheal dilatation can be seen in the inspiratory phase, and reduced diameter or collapse is seen upon expiration. Magnetic resonance imaging has the advantage of not emitting ionizing radiation but has low sensitivity for detecting and characterizing existing parenchymal alterations.

REFERENCES:

1. Woodring JH, Howard RS, Rehm SR. Congenital tracheobronchomegaly (Mounier-Kuhn syndrome): a report of 10 cases and review of the literature. J Thorac Imaging 1991; 6(2):1-10.

2. Jain P, Dave M, Singh DP, Kumawat DC, Babel CS. Mounier-Kuhn syndrome. Indian J Chest Dis Allied Sci 2002; 44:195-8.

3. Genta PR, Costa MVO, Stelmach R, Cukier A. A 26-yr-old male with recurrent respiratory infections. Eur Respir J 2003; 22:564-7.

4. Lazzarini-de-Oliveira LC, Franco CACB, Salles CLG, Oliveira AC. A 38-Year-Old Man With Tracheomegaly, Tracheal Diverticulosis, and Bronchiectasis. Chest 2001; 120:1018-20.

5. Nobrega B, Barcelos F, Sizenildo S, Cavalcante LP. Traqueobroncomegalia (syndrome de Mounier-Kuhn): relato de caso e revisão da literatura. Radiol Bras; 2002; 35(3):187-9.

Correct diagnoses of the case presented in the Jan/Feb 2005 Issue were submitted by:

Arismar Léon Pereira - Prever-Centro radiológico, Brasilia, DF

Arnaldo Jose Noronha Filho - Universidade Estadual do Rio de Janeiro, Rio de Janeiro, RJ

Carlos A. C. Pereira - Universidade Federal de São Paulo, São Paulo, SP

Celso Murilo Nálio Matias de Faria - Hospital de Base de São José do Rio Preto, SP

Cristian Cremonez Vogas - Universidade Federal Fluminense, Niterói, RJ

Cristiano Feijo Andrade - Irmandade Santa Casa de Misericordia de Porto Alegre, RS

Gislleny Nunes Calanzani Rocha - Prefeitura Municipal de São José dos Campos, SP

Jorge Luiz Pereira-Silva - Universidade Federal da Bahia, Salvador, BA

Karen Cristina de Paula Batista - Hospital Universitário Sul Fluminense, Vassouras, RJ

Leandro Baptista Pinto - Santa Casa de Misericórdia, Cachoeiro de Itapemirim, ES

Lílian Pinto de Azevedo Oliveira - SAMER Hospital, Resende, RJ

Marcio Abreu Neis - Hosp Heliópolis/Fac.Medicina ABC, Santo André, SP

Maria do Socorro de Lucena Cardoso - Universidade Federal do Amazonas, Manaus, AM

Marina da Rocha Lordelo - Universidade Federal da Bahia, Salvador, BA

Mario Ghefter - Hospital do Servidor Publico Estadual, São Paulo, SP

Pablo Gerardo Sanchez, Porto Alegre, RS

Pollyana Pereira Camargo - Hospital do Servidor Publico Estadual de São Paulo, São Paulo, SP

Ricardo Domingos Delduque - Hospital Emilio Carlos, Catanduva, SP

Rodrigo Tamer Sertorio - Hospital Regina, Novo Hamburgo, RS

Rogerio Antonio Silva - Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ

Rosane Rodrigues Martins - Hospital Universitario de Brasilia, DF

Rubens Gabriel Feijo Andrade - Universidade Federal de Santa Maria, Santa Maria, RS

Simone Fortaleza - Hospital de Messejana, Fortaleza, CE

Virgilio Alexandre Nunes de Aguiar - Faculdade de Medicina UNIMES, Santos, SP

Vivianne Calheiros Chaves Gomes - Hospital Infantil Albert Sabin, Fortaleza, CE

Wagner Malheiros - Diagnóstico e Imagem, Juina, MT

Publication Dates

• Publication in this collection
  14 July 2005
• Date of issue
  Apr 2005