Overuse injuries are very common in children and teenagers, especially among kids who play sports throughout the year.

Although rare, primary systemic vasculitis in children is associated with significant mortality and morbidity when not properly treated. Optimal management of the group of multiorgan inflammatory conditions is hampered by the lack of evidence-based therapies. This shortage of data has been attributed, in part, to the absence of a standardized outcome measure for use in clinical trials, according to Dr. Pavla Dolezalova.

"Until recently, no standardized vasculitis activity assessment tool has been available for children, so some pediatric studies apply adult measures, such as the Birmingham Vasculitis Activity Score [BVAS]," she said. Further, although nonspecific inflammatory markers such as erythrocyte sedimentation rate or C-reactive protein can reflect systemic vasculitis disease activity, they do not distinguish it from infectious complications. Use of the global assessment of disease activity by the treating physician using the visual analog scale is of limited utility in clinical trials, she noted.

In an effort to facilitate more informative clinical trials of primary systemic vasculitis in children, Dr. Dolezalova of Charles University and General University Hospital in Prague, Czech Republic, and her colleagues have developed a quantitative clinical index of manifestations of active disease, called the Pediatric Vasculitis Activity Score (PVAS), which has been preliminarily validated as a useful clinical measure with good interobserver reliability (Pediatr. Rheumatol. Online J. 2011 [doi:10.1186/1546-0096-9-S1-P92]).

In this column, Dr. Dolezalova describes the need for the assessment tool as well as some of the development challenges.

Question: Why are outcome assessment tools used for adults with systemic vasculitis not ideal for measuring disease activity in children?

Dr. Dolezalova: Tools used in adults are not fully applicable in children for multiple reasons. Disease presentations and outcome of primary systemic vasculitides appear to be different in children. Among the most obvious differences between adult and pediatric variants of the disease are the developmental and growth aspects; differences in functional, educational, and social impacts of longstanding disease; different drug pharmacokinetics and toxicity profiles; and the absence of comorbidities in children.

Question: What specific features have been incorporated into the PVAS?

Dr. Dolezalova: The development of the pediatric-specific tool has been a result of an international collaborative effort of pediatric rheumatologists from the vasculitis working groups of PReS (Pediatric Rheumatology European Society) and CARRA (North American Childhood Arthritis & Rheumatology Research Alliance), with the help of the European Vasculitis Study Group (EUVAS). We adapted the Birmingham Vasculitis Activity Score (BVAS 2003), the most commonly used tool in adult vasculitis patients, into PVAS. It is a systematic clinical scoring system that identifies selected features of active vasculitis in nine organ systems. Based on the analysis of the most common systemic vasculitis presentations in children reported to the PReS/PRINTO (Pediatric Rheumatology International Trials Organization) vasculitis registry, eight pediatric-relevant items and their definitions were added to the original BVAS 2003 in the cutaneous, cardiovascular, and abdominal systems. Additionally, by consensus, the maximum score for each organ system was to remain unchanged to facilitate longitudinal congruity with the BVAS. Among the 56 BVAS 2003 items, we redefined 22 for pediatric use.