Intrarenal hemodynamics and impaired tubular functions in patients with systemic lupus erythematosus

Abstract

Objective. To identify intrarenal hemodynamic disorders in patients with systemic lupus erythematosus (SLE), to assess their prognostic role, and to reveal an association between tubular dysfunction and intraglomerular hemodynamics.
Subjects and methods. Twenty-nine SLE patients, 86.2% of them were diagnosed as having a renal lesion, were examined. The levels of ethanolamine, uric acid, calcium, and phosphorus were determined in their daily urine and serum; the renal functional reserve (RFR) was estimated to detect intrarenal hemodynamic disorders.
Results. In the patients with SLE, RFR was considerably smaller: by an average of 6.0% (-25.9; 49.5%) than that in the control group: by an average of 30.9% (16.6; 46.8%); p <0.01. There was a direct correlation between the blood levels of ethanolamine and phosphorus, daily phosphorus excretion, and phosphate clearance and a correlation between the blood content of calcium and its clearance in relation to the RFR (p < 0.05).
Conclusion. The smaller and no RFR in patients without signs of nephropathy may suggest occult intrarenal hemodynamic disorders detected during the dopamine stress test. Tubular impairments in SLE were largely characteristic of patients with intrarenal hemodynamic disorders.