Tracheobronchomalacia in Hunter's syndrome

Hunter's syndrome is one of a group of heritable metabolic disorders caused by decreased activity of one or more of the lysosomal enzymes responsible for mucopolysaccharide catabolism, resulting in excessive deposition of mucopolysaccharides in skeletal and soft tissues. Pulmonary conditions, such as airway obstruction, sleep apnea syndrome, atalectasis, recurrent pneumonia and difficult endotracheal intubation are known to be associated with these rare disorders and have been reported. We report the findings at laryngotracheobronchoscopy of a patient with Hunter's syndrome with airway symptoms and, supported by analysis of previously reported cases of airway problems associated with the syndrome, suggest that tracheobronchomalacia with classifiable major airway collapse (MAC) may be the pathological correlate for this clinical picture. The endoscopic technique and characteristic findings of tracheobronchomalacia/MAC are discussed, as well as the natural history and pathophysiology of this condition, which is characterized by weakness of the tracheal wall due to softening of the supporting cartilage and hypotonia of the myoelastic elements with reduction in the tracheal lumen.