[Urinary myelin bodies and the nephrotoxicity of aminoglycosides]

In a significant number of cases, the administration of aminoglycosides induces renal failure. Electron microscopy has now shown that the renal lesion is mainly characterised by the appearance of myelin figures (myeloid bodies) in lysosomes of proximal convoluted tubules. These figures are then eliminated by urinary excretion. The search for and quantification of the myelin figures in urinary sediment seems to us to link the renal failure to the administration of aminoglycosides. Our study is based on 75 patients: 54 received aminoglycosides and 21 were controls. In each case myelin figures in the urinary sediment were grouped into one of 6 classes (O to V) according to their quantity. Comparison of the results with clinical factors showed 3 different correlations: 1) between the presence of myelin figures in the urine and the administration of aminoglycosides; 2) between the quantity of myelin figures and the accumulated dose of aminoglycosides; 3) between the quantity of myelin figures and obvious renal failure. The absence of myelin figures in control patients attests to their diagnostic value. Urine analysis to detect myelin figure appears to be a reliable technique in confirming the aminoglycoside's origin of an acute renal failure. It would also aid in determining and evaluating aminoglycoside nephrotoxicity in animal experimentation and human pathology. Since this method is non invasive, repeated studies are possible in man as well as animals.