Pulmonary function in children affected by juvenile spondyloarthropathy

Pleuropulmonary involvement in adult spondyloarthropathy (SpA) has been thoroughly investigated. SpA is usually detected by conventional radiology as fibrosis of the upper lobes in about 30% of asymptomatic patients. Pulmonary function tests (PFT) reveal decreased vital capacity and total lung capacity, as well as increased residual volume. Juvenile SpA (JSpA) is a rare clinical condition, and no extensive investigations have been carried out on pulmonary involvement in JSpA. We studied prevalence and features of PFT alterations in patients with JSpA over a 2 year followup and analyzed the relationship between PFT and disease duration, disease activity, and chest and spine mobility.

Eighteen patients with JSpA, with no clinical signs of lung disease and normal chest radiographs, underwent PFT--static and dynamic volumes, diffusing capacity for carbon monoxide (DLCO), at enrollment (T0), at 12 months (T1), and at 24 months later (T2). Disease activity was defined at each investigation by clinical and hematological data.

Significant functional lung impairment was detected in 33% of patients (reduced forced vital capacity in 22% and DLCO in 11%). No significant change in the prevalence and features of PFT alterations was detected at T1 and T2; no relationship was found between PFT and duration, activity, and clinical scores of the disease.

Thirty-three percent of JSpA patients without clinical symptoms and no radiological findings of lung involvement show PFT alterations, mainly characterized by a restrictive pattern. No progression or modification in PFT developed over 2 years. No correlation was found between PFT and disease duration, activity, and clinical scores.