SESSION TITLE: Genetic and Developmental Disorders Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM
PURPOSE: Mucopolysaccharidosis type 2 (MPS2) is a rare X-linked lysosomal storage disease characterized by accumulation of glycosaminoglycans (GAGs) in various organs and tissues.1 Deposition of CAGs in tissue of the throat and trachea is thought to be responsible for progressive airway dysfunction and laryngeal and tracheal obstruction in this disease. Dyspnea is a frequent symptom in MPS2 with partially unknown etiology. The occurrence of tracheal narrowing and changes of shape of the trachea have previously been described in children with MPS. 2,3 We studied the severity and prevalence of tracheobronchomalacia in adult MPS2 patients.
METHODS: All five adult MPS2 patients (mean age 40 years) treated at the Erasmus Medical Center were included. Repeated routine pulmonary function tests were obtained during several years of follow-up. Analysing respiratory symptoms, we performed in- and expiratory chest CT scans in all patients. The cross-sectional area of trachea and main bronchi were measured at end-inspiration and -expiration and the percentage collapse was calculated.
RESULTS: There was a diffuse narrowing of the entire intra-thoracic trachea and the main bronchi and a severe expiratory collapse of the trachea in all patients. At 1 cm above the aortic arch the median % collapse of the trachea was 68% (range 60 to 77%), at the level of the aortic arch 64% (21-93%) and at 2 cm above the carina 49% (0-83%). The collapse of the main bronchi, measured at 1 cm below carina was 58% (26-66%) on the left side and 44% (9-76%) on the right side. Pulmonary function tests showed obstructive airway disease in all but one patient (FEV1 ranged from 18-62%). The fifth patient had restrictive airway disease with a very small total lung volume (TLCHe 49%).
CONCLUSIONS: In adult MPS 2 patients central airway calibre is strikingly reduced and upon expiration there is a severe collapse of the trachea and main bronchi. This is the first study to show dramatic narrowing of the trachea and main bronchi in adult MPS2 patients during expiration.
CLINICAL IMPLICATIONS: Severe respiratory symptoms in MPS2 patients can be explained by the observed tracheal and bronchial collapse and abnormal lung function results. Because of the very specific nature of the airway pathology it requires tailored therapy, with for example modified non-invasive ventilation. We recommend to include dynamic airway imaging in the assessment of pulmonary symptoms in MPS2 patients.
DISCLOSURE: The following authors have nothing to disclose: Marijke Rutten, Pierluigi Ciet, Ries van den Biggelaar, Esmee Oussoren, Janneke Langendonk, Ans van der Ploeg, Mirjam Langeveld
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