[Criteria for classification of spondylarthropathies in children]

The term spondylarthropathy is used for several different entities including undifferentiated forms. The latter are particularly frequent in children and often not recognized. Two sets of criteria, the Amor and the European Spondylarthropathy Study Group (ESSG) criteria, primarily devised for adults, were evaluated in a pediatric population.

Three hundred and ten consecutive patients referred to one pediatric rheumatology center over 6 months were prospectively assessed, whatever the rheumatic complaint. Twenty two items were analysed for each patient and compared with the criteria proposed by Amor (17 items) and the ESSG (12 items).

The Amor criteria performed better than the ESSG criteria. The sensitivity was 84 and 69.7%, and the specificity 96.1 and 92.2% for the Amor and the ESSG criteria, respectively. The sensitivity for pauci-arthritis was much higher in children, but the specificity was lower than in adults. The sensitivity of spinal involvement was very low in children. The undifferentiated type accounted for 81% of all definite spondylarthropathies. Definite and possible spondylarthropathies were 17% of the total referral over the 6 months, i.e. one patient in 6.

These two sets of criteria, particularly the Amor criteria, can help pediatricians to recognize the undifferentiated type of spondylarthropathy, in the absence of spinal or any other characteristic manifestation.