General and segmental reduced pain thresholds in juvenile chronic arthritis.

The objective of this work was to investigate the pattern of pain threshold (PT) alterations in paraspinal soft tissues as related to inflamed joints in patients with juvenile chronic arthritis (JCA). A pressure algometer was used in JCA patients with inflamed knee(s) (n = 16), with inflamed ankle(s) (n = 17), and in healthy controls (n = 69), all aged 6-17 years. Local pressure was applied to the joint capsules of the knees and ankles and the soft paraspinal tissues, and PTs were recorded. JCA patients showed not only a significantly lower PT at the inflamed knee and ankle joints, but also in the non-inflamed paraspinal areas. All paraspinal PTs showed a significant negative correlation with the inflamed knee or ankle joint. The correlation rank order showed that the paraspinal L1 area had the highest negative correlation with the inflamed knee joint and the paraspinal L3 area with the inflamed ankle joint. JCA coincides with generally diminished pain thresholds in the paraspinal region. Nociception from inflamed joints may have established changes in the peripheral as well as central nociceptive processing system in JCA.