Assessment of respiratory involvement in children with mucoplysaccharidosis using pulmonary function tests

ABSTRACT

Mucopolysaccharidosis [MPS] are classified into seven clinical types based on eleven known lysosomal enzyme deficiencies of glycosaminoglycan [GAG] metabolism. Respiratory involvement seen in most MPS types includes recurrent respiratory infections, upper and lower airway obstruction, tracheomalacia, restrictive lung disease, and sleep disturbances. To delineate the pattern of respiratory compromise and pulmonary function abnormalities in MPS patients. This is a cross section observational study conducted on 30 patients recruited from the Neurometabolic Clinic, Children's Hospital, Cairo University over a period of 18 months. All patients were screened first by the quantitative determination of GAGs in urine, and diagnosis was confirmed by unidimensional electrophoresis for GAGs in urine and/or specific enzymatic assay in blood leucocytes. Infant pulmonary functions [IPFT] were done in twenty-two patients [< 3 years of age], while 8 cases performed impulse oscillometry [IOS] test [3-6 years of age]. Ages at diagnosis ranged from 1 to 9 years with a median of 2.3 years. Male to female ratio was 41. Consanguinity was observed in 53.3% whereas similar family condition was present in 40% of cases. Lumbar kyphosis was detected in 60% of cases, while scoliosis was detected in 46.7%. Results of pulmonary functions were mainly obstructive in 20 [66.6%] cases; however, combined obstructive and restrictive were detected in only 6 [20%] of cases. Data showed no association between the presence of scoliosis or the presence of organomegaly and the pattern of pulmonary function abnormalities. Evaluation and follow up of patients with MPS using pulmonary function tests are essential to detect early involvement of respiratory system and hence start treatment for respiratory complications early in the course of the disease