Proteinuria produced by urographic contrast media.

All angiographic and urographic procedures expose the kidney to high contrast medium concentrations. The introduction of the triiodinated ionic contrast media has lowered the risk of contrast medium-induced renal damage. An increase in dose and use of "bolus urography" have, however, led to an increase in frequency of reports on renal damage following intravenous pyelography and angiography. The low general toxicity of the new nonionic contrast media should also include a lower toxicity towards the kidneys. The media are, however, concentrated in the kidney to twice the concentration of the ionic media, and this might blur the expected reduction in kidney toxicity. The authors examined this problem by studying enzymuria in rabbits and albuminuria in rats after injection of different ionic and nonionic contrast media. In the rabbit, the model should imitate a urography and in the rat, a nephroangiography. All contrast media resulted in enzymuria and albuminuria, but to different degrees. The time for maximum enzymuria differed from the time of maximum albuminuria. The proteinuria does not appear to be related to the osmotic pressure of the injected contrast medium. The clinical significance of these findings is discussed.