[Characterization of proteinuria in patients with ulcerative colitis and therapy with aminosalicylates]

Patients with ulcerative colitis have a higher rate of tubular nephropathies. Data concerning the cause of these lesions is rare and inconsistent, the occurrence may be part of the disease itself or a side effect of 5-aminosalicylates (5-ASA). This study investigated proteinuria and eosinophiluria in patients with moderate ulcerative colitis under treatment with 5-ASA.

Urine specimens (microelectrophoresis and eosinophiluria) of 34 patients with acute onset of moderate ulcerative colitis who were treated only with 5-ASA as active drug were analyzed.

Data of 27 patients could be evaluated. Twelve patients had tubular proteinuria previous to treatment. By the end of the study, urine specimens normalized in six, in further six the proteinuria remained unaltered, two patients developed proteinuria under treatment. In 14 patients, proteinuria was not detectable at any time. Eosinophiluria was found in none of the specimens.

Under treatment with 5-ASA no toxic or allergic nephropathy developed. One initially pathologic urine specimen normalized under treatment coming along with remission of the intestinal symptoms and histological findings. This indicates an association between the activity of the ulcerative colitis and might be caused by renal excretion of pro-inflammatory cytokines.