Letter to the Editor Mounier-Kuhn syndrome: a rare and often overlooked cause of bronchial dilation and recurrent respiratory tract infections Síndrome de Mounier-Kuhn: uma causa rara e muitas vezes negligenciada de dilatação brônquica e de infecções recorrentes do trato respiratório Shailendra Kapoor To the Editor: I read with great interest the recent article criteria include a right main bronchus diameter by García et al.(1) It should be noted that one greater than 24 mm or a left main bronchus rare, often overlooked and underrecognized, diameter greater than 23 mm. The widening cause of respiratory tract infections and bronchial is accompanied by marked bronchiectasis.(3,6) dilation is Mounier-Kuhn syndrome (MKS). A few patients develop pneumothorax. Some The primary feature of MKS, also known as patients initially present with a pneumothorax “tracheobronchopathia malacia”, is congenital that reveals the underlying MKS. For instance, tracheal dilation accompanied by dilation of the in a recent report of the case of a 54-year-old main bronchi.(2) The dilation occurs secondary to patient presenting with left-sided pneumothorax, muscular layer degeneration of the trachea and further evaluation revealed the underlying cause bronchi. Tracheal dilations as large as 36 mm to be MKS.(9) Significantly dilated airways are have been reported in MKS. The syndrome most typically seen on bronchoscopic evaluation. often affects adults between 30 and 40 years of The results of pulmonary function tests can be age, predominantly males.(3) It is rarely diagnosed normal or abnormal. in pediatric patients and usually accompanies The management of MKS primarily involves disorders such as cutis laxa. There are numerous the institution of supportive measures. Antibiotics presentations of MKS. For instance, Randak et al. need to be started immediately in patients with recently reported the case of a patient with MKS respiratory tract infections.(5) Chest physiotherapy who developed concurrent tracheal diverticula.(4) is advised in most patients. Laser therapy is Patients with MKS typically develop recurrent another emerging alternative. Dutau et al. recently lower respiratory tract infections. Such patients reported the successful management of a patient can also develop rare forms of bacterial infections. with MKS by the use of yttrium-aluminum-garnet For instance, Arroyo-Cózar et al. recently described laser endoscopically.(10) Collapse of the tracheal airway might necessitate endobronchial stenting. the case of a 75-year-old male with MKS who Odell et al. recently reported considerable success developed a respiratory infection with Alcaligenes with such stenting.(11) Another surgical procedure xylosoxidans.(5) Recurrent bronchiectasis and that can be considered in patients with severe pneumonia are frequently seen. Patients might forms of MKS is tracheobronchoplasty. also present with intermittent dyspnea. Cough- It is obvious that MKS is a rare yet significant induced syncope is often seen. Hemoptysis is cause of respiratory tract infections. It should rare but has been reported. Pulmonary fibrosis be included in the differential diagnosis of can further complicate the course of the disease, patients with lower respiratory tract infections as can emphysema. Rapid progression of the and concurrent tracheal dilation on imaging. disease can result in respiratory failure. Although recently reported by Dincer et al.,(6) vocal cord Shailendra Kapoor paralysis is rarely seen in MKS patients. Physician, Private Practice, Imaging with CT goes a long way toward confirming the diagnosis of MKS.(7) Such imaging, Chicago, IL, USA especially HRCT scans, typically reveal widening References of the trachea and main bronchi. When the tracheal diameter exceeds 30 mm, a formal 1. González-García M, Maldonado Gomez D, Torres-Duque diagnosis of MKS can be made.(8) Other diagnostic CA, Barrero M, Jaramillo Villegas C, Pérez JM, et al. J Bras Pneumol. 2014;40(1):96-97 Mounier-Kuhn syndrome: a rare and often overlooked cause of 97 bronchial dilation and recurrent respiratory tract infections Tomographic and functional findings in severe COPD: el artículo de las diferencias tomográficas y comparison between the wood smoke-related and smoking- funcionales entre la EPOC severa relacionada related disease. J Bras Pneumol. 2013;39(2):147-54. con humo de leña y con cigarrillo, es importante http://dx.doi.org/10.1590/S1806-37132013000200005 PMid:23670499 aclarar que hay diferencias significativas en el 2. Dalar L, Eryüksel E, Kosar F, Karasulu AL, Urer N, Sökücü compromiso de la vía aérea entre los pacientes SN, et al. Central airway obstruction due to malignant con este síndrome y la EPOC por humo de fibrous histiocytoma metastasis in a case with Mounier- Kuhn syndrome. Tuberk Toraks. 2012;60(2):167-71. leña. Aunque las dilataciones y engrosamiento http://dx.doi.org/10.5578/tt.2458 PMid:22779939 bronquial son frecuentes en la EPOC por 3. Marchiori E, Sousa AS Jr, Zanetti G, Hochhegger B. exposición a humo de leña, no encontramos Mounier-Kuhn syndrome: The role of bronchiectasis in en las imágenes tomográficas dilatación de la clinical presentation. Ann Thorac Med. 2012;7(1):51. http:// dx.doi.org/10.4103/1817-1737.91549 PMid:22347353 tráquea y los bronquios principales,(1) que es la PMCid:PMC3277044 principal característica del síndrome de Mounier- 4. Randak CO, Weinberger M. A child with progressive Kuhn. Los hallazgos en nuestras pacientes de multiple tracheal diverticulae: a variation of the Mounier- Kuhn syndrome. Pediatr Pulmonol. 2013;48(8):841-3. compromiso bronquial y atelectasias, sin daño http://dx.doi.org/10.1002/ppul.22663 PMid:22949127 aparente de tráquea o bronquios fuente, están 5. Arroyo-Cózar M, Ruiz-García M, Merlos EM, Vielba de acuerdo a la descripción realizada por Moreira D, Macías E. Case report: respiratory infection due to et al.(2) en otro artículo del mismo número de la Alcaligenes xylosoxidans in a patient with Mounier-Kuhn syndrome [Article in Spanish]. Rev Chilena Infectol. revista. Adicionalmente, los pacientes con EPOC 2012;29(5):570-1. http://dx.doi.org/10.4067/S0716- relacionada con el humo de la leña comparten 10182012000600019 PMid:23282506 algunas características clínicas con la EPOC por 6. Dincer HE, Holweger JD. Mounier-Kuhn syndrome and bilateral vocal cord paralysis. J Bronchology Interv tabaquismo e infrecuentemente se presentan Pulmonol. 2012;19(3):255-7. http://dx.doi.org/10.1097/ infecciones bacterianas por gérmenes inusuales. LBR.0b013e318261009e PMid:23207474 Por la presentación de bronquiectasias tanto 7. Jaiswal AK, Munjal S, Singla R, Jain V, Behera D. A en la EPOC por leña como en el síndrome de 46-year-old man with tracheomegaly, tracheal diverticulosis, and bronchiectasis: Mounier-Kuhn syndrome. Lung India. Mounier-Kuhn, las dos entidades deben tenerse 2012;29(2):176-8. http://dx.doi.org/10.4103/0970- en cuenta en el diagnóstico diferencial del adulto 2113.95337 PMid:22628937 PMCid:PMC3354496 con enfermedad bronquial crónica. 8. Kent BD, Sulaiman I, Akasheh NB, Nadarajan P, Moloney E, Lane SJ. An unusual cause of spontaneous pneumothorax: the Mounier-Kuhn syndrome. Ir Med J. 2011;104(5):152-3. Mauricio González-García PMid:21736094 Médico, Fundación Neumológica 9. Celik B, Bilgin S, Yuksel C. Mounier-Kuhn syndrome: a rare cause of bronchial dilation. Tex Heart Inst J. Colombiana, Bogotá, Colombia 2011;38(2):194-6. PMid:21494536 PMCid:PMC3066798 10. Dutau H, Maldonado F, Breen DP, Colchen A. Endoscopic Referencias successful management of tracheobronchomalacia with laser: apropos of a Mounier-Kuhn syndrome. Eur J 1. González-García M, Maldonado Gomez D, Torres-Duque Cardiothorac Surg. 2011;39(6):e186-8. http://dx.doi. CA, Barrero M, Jaramillo Villegas C, Pérez JM, et al. org/10.1016/j.ejcts.2011.01.074 PMid:21382725 Tomographic and functional findings in severe COPD: 11. Odell DD, Shah A, Gangadharan SP, Majid A, Michaud G, comparison between the wood smoke-related and smoking- Herth F, et al. Airway stenting and tracheobronchoplasty related disease. J Bras Pneumol. 2013;39(2):147-54. improve respiratory symptoms in Mounier-Kuhn syndrome. http://dx.doi.org/10.1590/S1806-37132013000200005 Chest. 2011;140(4):867-73. http://dx.doi.org/10.1378/ PMid:23670499 chest.10-2010 PMid:21493699 2. Moreira MA, Barbosa MA, Queiroz MC, Teixeira KI, Torres PP, de Santana Júnior PJ, et al. Pulmonary changes on Respuesta de los autores: HRCT scans in nonsmoking females with COPD due to wood smoke exposure. J Bras Pneumol. 2013;39(2):155-63. Luego de leer la interesante descripción del http://dx.doi.org/10.1590/S1806-37132013000200006 síndrome de Mounier-Kuhn, en la cual cita PMid:23670500 Submitted: 24 September 2013. Accepted, after review: 7 October 2013. J Bras Pneumol. 2014;40(1):96-97