Correlation of Urinary Findings and Renal Pathology in Experimental Streptococcal Nephritis.

Abstract

The relation of the urinary to the kidney changes in experimental nephritis is of particular interest since in man, with few exceptions, we have been unable to do more than conjecture the cause of the different stages of nephritis, and to assume that in certain infections the concomitant acute nephritis lays the foundation for chronic diffuse renal disease months and years afterwards. Likewise, in human nephritis it is very difficult to compare any particular derangement of kidney function with the structural renal changes incident thereto.

This paper reports upon the sequence of the structural renal changes in correlation with the abnormal urinary findings in dogs in whom nephritis has been induced with the toxic product of Streptococcus scarlatinae. The results are especially noteworthy inasmuch as the kidney changes were produced with a nephritic agent that commonly causes nephritis in man, and a closer analogy could be drawn with the human disease than is possible where improbable excitants of human nephritis, like uranium nitrate, have been employed. The experiment has also afforded the opportunity to study the relation and sequence of the renal changes, and to trace the progress of their anatomical development.

Since nephritis frequently occurs spontaneously in the dog, we have used only young animals whose urine over a period of 10 days to 2 weeks was free from albumen, casts and other abnormalities; and whose kidney function, as determined by the phenolsulphenolphthalein test, was within the normal limits. During the period of observation the animals were kept in metabolism cages to facilitate the collection of urine. Catheterized specimens were not employed, so the figures for urine volumes are averages only, obtained by dividing the total urine volume of 7 days by the number of days in the period. Daily examinations of urine were made for abnormalities over a period of from one to 3 weeks after the administration of the nephrotoxic substance (killed culture and “Lysate” which had been prepared in vivo from the Streptococcus scarlatinae by the method of Duval and Hibbard 1 ).