Renal involvement in juvenile chronic arthritis: clinical and pathologic features.

Over an 18-year period, renal involvement was diagnosed in 13 patients, who represent 1% of the total juvenile chronic arthritis population referred to us. All had severe arthritis. This study illustrates the importance of renal biopsy and indicates that renal involvement in juvenile chronic arthritis is a heterogeneous group of diseases, with a variety of causes. In eight patients with nephrotic syndrome, renal biopsy revealed amyloidosis. One rapidly died of diffuse amyloidosis and infection. The other seven received chlorambucil. Disappearance of proteinuria was noted in three of them. Four patients have persistent proteinuria but normal serum creatinine. It is suggested that, despite the long-term oncogenic risk of the drug, chlorambucil may be beneficial in patients with amyloid deposits. In one patient, the nephrotic syndrome was attributed to systemic lupus erythematosus, and in another, the chance association of an arthritis and nephrotic syndrome with minimal glomerular changes was considered. Although drug responsibility is difficult to determine in these patients receiving several medications in association, the renal involvement presented by the remaining three patients was probably related to drug(s). Moreover, it is possible that the effect of the association of medications is deleterious to the kidney. Drug-induced nephropathy is usually reversible when drugs are stopped. Unfortunately, because of persistent joint pain, these patients will continue to require pain-relieving drugs over prolonged periods.