Thoracic Computed Tomography Scan and Bronchoscopy Appearance of Mounier-Kuhn Syndrome: A Case Report.

Mounier-Kuhn syndrome (MKS) is a rare congenital disease with an autosomal recessive inheritance pattern, characterized by an enlargement of the trachea and bronchi. MKS is secondary to a thinning of the muscular mucosa and atrophy of the longitudinal muscle and elastic fibers of the tracheobronchial tree. As a consequence, tracheal diverticulosis and dilatations in the posterior membranous wall appear, along with bronchiectasis that tend to be cystic in appearance. Overall, there is an impairment of mucocilliary clearance, with an ineffective cough, which predisposes the patient to recurrent lower respiratory tract infections. Clinical manifestations vary from asymptomatic to respiratory failure and death, most patients being diagnosed between the third and fourth decades of life. It is an often undiagnosed disease, with a diagnostic algorithm that includes the use of radiological techniques, alone or in combination with bronchoscopy. Specific diagnostic criteria have been developed, based on patients' tracheal and main bronchi diameter on chest X-ray and thoracic computed tomography scan. We present the case of a 45-year-old African American man who presented with a history of multiples episodes of pneumonia that required management in the intensive care unit, on whom MKS was diagnosed.