Clinicopathological characteristics and outcomes of pediatric patients with systemic small blood vessel vasculitis.

Background: Systemic small blood vessel vasculitis (SSV) is uncommon among pediatric patients, and the predictive value of the new histopathological classification for SSV in terms of renal outcomes in these patients is unknown. Methods: The study cohort comprised 38 pediatric patients and 285 adult patients with SSV who were treated in a medical center between 1993 and 2012. Results: Children accounted for 11.8 % of all patients with SSV diagnosed during the study period. In contrast to the adult patients, the pediatric patients were predominantly female (73.7 vs. 51.9 %; P < 0.05). The prevalence of skin purpura was higher and pulmonary symptoms were less common among pediatric patients than among adult ones (36.8 vs. 13.7 %, P < 0.01 and 26.3 vs. 46.0 %, P < 0.05, respectively). Subtype was correlated with the baseline levels of serum creatinine and treatment response among patients with SSV and was found to have a tendency to predict end-stage renal disease (ESRD) among pediatric patients (hazard ratio 2.273, P < 0.01). The probability of progressing to ESRD was highest in pediatric patients with the sclerotic glomerulonephritis subtype, followed by the mixed, crescentic and focal glomerulonephritis subtypes (in descending order of probability) ( P < 0.01). Conclusions: Estimated histopathological classification has a prognostic value for renal outcome and response to therapy in children with SSV. [ABSTRACT FROM AUTHOR]