Extent of subclinical pulmonary involvement in childhood onset systemic lupus erythematosus in the sultanate of oman.

OBJECTIVES

The aim of this study was to investigate the frequency of pulmonary function abnormalities in clinically asymptomatic children with Systemic Lupus Erythematosus and to determine the relationship of these abnormalities to clinical, laboratory, and immunological parameters as well as to disease activity.

METHODS

Forty-two children with childhood onset Systemic Lupus Erythematosus were included in this study. Demographic, clinical, laboratory and immunological parameters, as well as disease activity were assessed. Pulmonary function tests (PFT) were performed routinely to screen for subclinical lung disease.

RESULTS

Out of the 42 children, 19% (n=8) had clinical evidence of pulmonary involvement. The patients with no clinical evidence of pulmonary involvement (n=34) represent the study cohort. From our cohort of patients with no clinical evidence of pulmonary involvement 79% (n=27) had PFT abnormality; including 62% (n=21) had reduced FVC, 71% (n=24) had reduced FEV1, and 67% (n=12) had reduced DLCO. Similarly, 56% (n=15) had a restrictive PFT pattern, and 2.6% (n=2) had an obstructive PFT pattern, while 33% (n=7) had an isolated impairment of diffusion capacity. Due to small sample size; it was not possible to find a statistically significant difference between the cohort of asymptomatic SLE patients with abnormal PFT findings (n=27) and those with normal PFT findings (n=7) in terms of clinical, laboratory, immunological or disease activity index score.

CONCLUSION

Subclinical lung disease, as demonstrated by abnormal PFT in patients with normal radiographs, may be common but should be interpreted with caution as an early sign of lung disease. Although PFT studies do not correlate well with pulmonary symptoms in patients with childhood onset SLE, they nevertheless provide objective quantification of the type and severity of the functional lesions.