Section 2 Nephropathies in rheumatic diseases: therapeutic problems

Summary

Many of the connective tissue disorders are associated with renal pathology. Lupoid nephropathy is well documented, but 15 % of cases of rheumatoid disease also develop renal lesions, and of these patients 25 % die of renal failure. All this justifies an approach to the problem under the heading of ‘rheumatoid nephropathy’.

In such cases it is difficult to ascertain whether the renal lesions are due to the disease process or to previous medication. In the antirheumatic group of drugs gastro-intestinal upsets, skin rashes and cardiovascular problems are well recognised, but not the nephrotoxic potential of the drugs.

Groups of patients were chosen suffering from rheumatoid arthritis, rheumatic fever or systemic lupus erythematosus. The patients studied were being treated with either corticosteroids, gold salts, phenylbutazone or antimalarials. In a similar fashion, a group of 50 patients were treated for 6 weeks with ibuprofen, and two separate groups of 15 patients were treated with either antimalarials plus prednisolone, or antimalarials plus ibuprofen. Blood urea and creatinine clearance were measured and the urine examined for leucocytes, microscopic haematuria and proteinuria. The investigations were carried out before and after treatment and any correlation between therapy and renal abnormalities were noted.

It was found that most of the routinely used antirheumatic drugs tended to enhance renal problems but that following treatment with ibuprofen no adverse effects on renal function were noted that could be attributed to the drug. Proteinuria decreased in patients on corticosteroids and antimalarials, but the reduction was more marked with ibuprofen in cases with pre-existing nephrotic syndrome, pyelonephritis, and renal amyloidosis. Ibuprofen significantly decreased urinary leucocyte excretion whereas corticosteroids and phenylbutazone caused no obvious change. Microscopic haematuria persisted in those patients receiving corticosteroids, actually increased with phenylbutazone, but decreased with antimalarials and particularly so with ibuprofen.