MOUNIER-KUHN SYNDROME: A RARE CAUSE OF A COMMON DISEASE

Abstract

SESSION TITLE: Imaging SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 pm - 02:15 pm INTRODUCTION: Mounier-Kuhn syndrome is a rare disorder manifesting radiologically by marked dilatation of the trachea and main bronchi and symptomatically early in life with recurrent bronchopulmonary infection and bronchiectasis. We report a patient with late onset bronchiectasis caused by Mounier-Kuhn disease. CASE PRESENTATION: A 68-year-old male was hospitalized repeatedly for treatment of recurrent bronchopulmonary infection characterized by excessive sputum production, fever and worsening dyspnea. He was an ex-smoker with 36 pack-year smoking history. Chronic comorbidities include bilateral upper lobe smoke-induced centriacinar emphysema and idiopathic bilateral lower lobe bronchiectasis. Physical examination revealed a thin man with bilateral wheezing, clubbing, SpO2 of 90% on room air and temperature of 100.9 F. Labs were unremarkable except for leukocytosis. Chest x-ray demonstrated emphysema and persistent bibasilar opacities. He was treated with antibiotic, bronchodilator and nutritional support. CT chest without contrast showed predominantly lower lobe bronchiectasis with superimposed pneumonia. The trachea was dilated with a cross-sectional diameter of 40 mm; left and right main bronchi were 28 mm each. Pulmonary function testing revealed obstructive ventilatory defect with reduced FEV1/FVC ratio of 67% and FEV1 of 1.5 liters. Fiberoptic bronchoscopy revealed a very dilated trachea with an elliptical shape, with dynamic airway during suctioning and coughing. Copious amounts of mucopurulent secretions were aspirated from both lungs. Bronchoalveolar lavage was negative for bacteria. The bronchoscopy findings coupled with the findings on CT chest confirmed a diagnosis of Mounier-Kuhn syndrome. The patient was prescribed chest percussive device to promote mobilization of respiratory secretions to reduce recurrent bronchopulmonary infections. DISCUSSION: Mounier-Kuhn syndrome, also known as tracheobronchomegaly, is a rare condition that occurs due to congenital weakness/atrophy of the muscular and elastic tissue of the tracheal and bronchial walls. Clinical manifestations range from asymptomatic disease to recurrent lower respiratory infections progressing to severe respiratory failure and death. Diagnosis is made by CT: diagnostic criteria are tracheal diameter >30mm, right bronchial diameter >24mm and left bronchial diameter >23mm. Symptomatic patients are treated with chest physiotherapy and antibiotics during bouts of infection. Tracheal stenting and tracheobronchoplasty may be needed in severe cases. This patient had a history of recurrent lower respiratory infections, met CT criteria and demonstrated characteristic findings of Mounier-Kuhn syndrome. CONCLUSIONS: Mounier-Kuhn syndrome is characterized by dilation of the trachea, impaired clearance of airways secretions and recurrent lower respiratory infections that can lead to bronchiectasis; diagnosis is made radiologically by CT. Reference #1: Celik B, Bilgin S, Yuksel C. Mounier-Kuhn Syndrome: A Rare Cause of Bronchial Dilation. TEXAS HEART INSTITUTE JOURNAL. 2011;38:194-196. Reference #2: Simkins A, Maiti A, Cherian SV, Trujillo DO, Estrada-Y-Martin RM. Mounier-Kuhn syndrome. Postgraduate Medical Journal. 2017;93:642-642. Reference #3: Simon M, Vremaroiu P, Andrei F. Mounier-Kuhn syndrome. Journal of bronchology& interventional pulmonology. 2014;21:145. DISCLOSURES: No relevant relationships by Mona Alipour, source=Web Response No relevant relationships by Farhad Arjomand, source=Web Response No relevant relationships by Jennifer Chiu, source=Web Response No relevant relationships by Louis Gerolemou, source=Web Response No relevant relationships by Nabil Mesiha, source=Web Response No relevant relationships by Ankur Mogla, source=Web Response No relevant relationships by Viswanath Vasudevan, source=Web Response