A marked dilation of the trachea and main bronchi, associated with a higher rate of recurrent lower respiratory tract infections, characterizes the Mounier-Kuhn syndrome (MKS).
The clinical presentation varies widely from minimal respiratory discomfort, repetitive respiratory infections, mucus accumulation and ineffective cough, to severe respiratory failure. This syndrome is considered to be congenital, although most of the times it presents in the third or later decades with recurrent respiratory tract infections. The aetiology is uncertain, anatomo-pathological findings have led to believe it due to the lack of smooth muscle and elastic connective tissue in the trachea and main bronchi, causing tracheobronchomegaly and “herniation” of diverticula between the cartilaginous rings.
Frequently the diagnosis can be sensed based on cases of abnormal chest X-ray, and an anaesthesiologist should be suspected it when there is an unexplainable loss of air during ventilation with tracheal tube, but it needs to be confirmed by a CT scan to allow for precise measurement of airways and evaluation of additional changes in pulmonary tissues, and possibly a bronchoscopy could be considered for additional evaluation.
The treatment does not include surgery and typically includes supportive measures and possible airway stenting in cases of significant tracheomalacia, but surgery has also been attempted. The only clinical trial which included 12 patients with Mounier-Kuhn syndrome showed significant improvements in pulmonary function and quality of life when compared to baseline. The objective of conservative treatment is sputum clearance, using positional physiotherapy and early and aggressive treatment of pulmonary infections. In some cases, chronic prophylactic administration of antibiotics may be required.