The Kidney in Lead Poisoning

Kidney damage due to lead is still an interesting problem of industrial toxicology. In spite of abundant literature data, much still remains to be explained. There are controversial opinions, not only on the type of renal lesions due to lead, but also on whether lead affects the kidney at all.

In this paper our clinical observations on the effect of lead upon the kidney in 53 patients suffering from lead poisoning are presented. In 44 patients (40 men and four women) lead poisoning was due to occupation, and in nine (five men and four women) to the use of lead-glazed pottery. The length of exposure varied from two months to 35 years. In all cases the diagnosis of lead poisoning was made clinically and confirmed by laboratory tests.

Permanent changes in the form of chronic nephropathy were observed in only two patients. These were the two cases in which exposure to lead was the longest and most intense. Twenty-three patients showed functional renal lesions tending to normalize. In addition to the cases of organic nephropathy, blood pressure was persistently raised in one further patient; in two patients a raised blood pressure was observed only in the acute stage of poisoning.

On the basis of these findings we consider that lead intoxication can cause renal lesions. These lesions are for the most part functional and temporary. In cases of long and severe exposure and repeated lead intoxication, organic renal lesions seem possible. The disturbances of renal function observed in this study may be ascribed to disordered intrarenal circulation, due to the spastic effect of lead on intrarenal blood vessels, and to a direct toxic or indirect hypoxic effect of lead on the tubules.

When investigating renal function, we have observed that the timing of individual tests is of paramount importance. Some lesions are subject to changes in the natural course of lead poisoning, and unless this is borne in mind, apparently contradictory results may be obtained.