Hypoxemic pneumonia revealing Mounier-Kuhn syndrome: A case report

Mounier-Kuhn syndrome, or tracheobronchomegaly (TBM), is named after P. Mounier-Kuhn, who first described the condition in 1937 [1]. It is a rare disease with an origin that is still debated, whether congenital or acquired. The condition is characterized by a marked dilation of the trachea and proximal bronchi, resulting from thinning of the smooth muscle layer and atrophy or absence of elastic fibers. TBM is significantly more common in men [2]. The average age at diagnosis ranges from 30 to 60 years [3]. Although the exact cause of TBM remains to be determined, smoking and environmental pollutants are considered exacerbating factors that lead to airway inflammation [3]. Chronic cough with sputum production, accompanied by recurrent lower respiratory tract infections, characterizes the clinical presentation [4]. The clinical signs are not very specific. The radiological diagnosis is often straightforward on chest X-ray and CT scan. It is based on the measurement of the diameter or surface area of the trachea and main bronchi. Imaging is also essential for assessing the impact on the lung parenchyma. There is no curative treatment available [5]. We present the case of a 48-year-old man who was admitted to our pulmonology department for the management of acute pneumonia. During clinical evaluation and supplementary tests, tracheal and main bronchial dilation were noted, leading to the fortuitous discovery of Mounier-Kuhn syndrome.