CT and endoscopic evaluation of larynx and trachea in mucopolysaccharidoses

Mucopolysaccharidoses (MPSs) are lysosomal storage disorders caused by lysosomal enzyme deficiencies that result in systemic accumulation of glycosaminoglycans (GAGs). Accumulation of GAGs in the upper airway can lead to respiratory failure. The aim of this study was to investigate changes of the airway by flexible endoscopy and CT.

Thirty-five patients aging from 2 to 16 years (mean: 9.2±4.4 years) participated in this study. The majority had MPS I (n=5) or MPS II (n=25). The shape of the trachea and the cross-sectional trachea surface area (TSA) was determined at the Th1 and Th2 levels. Airway obstruction was evaluated from endoscopic findings and classified into 3 grades (Grades 0, 1, and 2). Forty-five patients in the control group who underwent tracheal CT for other conditions were retrospectively selected from the database.

Tracheal morphology was abnormal in 50-60%, which showed a transversely collapsing narrow trachea. Tracheal deformity was severe in MPS II and MPS IV. The mean TSA of the MPS patients was 55.5±29.0 mm(2) at Th1 and 61.4±29.0 mm(2) at Th2, while that of the control group was 90.1±41.9 mm(2) and 87.9±39.3 mm(2), respectively. Respiratory distress was noted in 15 of the 35 patients, among whom 7 patients showed tracheal deformity and 7 patients had laryngeal redundancy. Three patients had no abnormalities of the larynx or trachea, so other factors such as pharyngeal stenosis or lower airway stenosis might have contributed to their respiratory distress.

CT and flexible endoscopy allow quantitative and morphological evaluation of airway narrowing, which is beneficial for airway management in MPS children.