Henoch-Schonlein nephritis in children and adults - Morphological featuresand clinicopathological correlations

Rheumatoid purpura or Henoch-Schonlein syndrome is an IgA vasculitis affect ing small vessels, The acute disease progresses by successive flare-ups of limited duration. Long-term prognosis depends mainly on the degree of initi al renal damage, A review of the literature shows that renal involvement occurs in about 33% of children and 63% of adults with rheumatoid purpura. The most typical ma nifestation is segmentary focal glomerulonephritis, always associated with granulous IgA deposits in the mesangium. When renal signs are severe enough to warrant renal biopsy (generally at urine protein > 1 g/d and/or organic renal failure) the risk of developing chronic renal failure is 18% in chil dren and 28% in adults. The best prognostic features are histological. The percentage of crescents, the presence of interstitial fibrosis and the pres ence of dense sub-epithelial deposits are correlated with risk of chronic r enal failure, This risk is high (47%) in children with crescents in more th an half the glomeruli. In adults, the percentage of crescents associated wi th unfavorable course appears to be lower than 50%. Predictions are only va lid if no further renal flare-up occurs. In addition, histology cannot prec isely predict the course of persistent renal sequelae, The severity of sequ elae determines the risk and the rapidity of developing chronic renal failu re. It is thus recommended to follow patients with Henoch-Schonlein nephrit is for long periods.