The photograph on the left is of a different kidney, but I would like you to see here a paleness, maybe some discoloration, and I would like you to imagine that the cut edge is very moist and this kidney here is probably a subacute or chronic version of the previous one and, hence, the cortex is a bit thin in this photo. That is because there has been considerable loss of renal tubular epithelium, maybe a bit of fibrosis. Can you see the surface on this photo is a bit dimpled or roughened and maybe has some grey streaks in it? Those are manifestations of scarring and shrinkage.
The right photograph is a close-up of a cut edge of another kidney that shows striation which is relatively parallel. It, I think, shows the moistness and certainly a pale cortex and the paleness extends clear to the surface. That is significant finding. Now all these slides represent instances of nephrosis, so-called acute tubular necrosis, a noninflammatory degenerative lesion of the renal tubular epithelium (chiefly the cortical epithelium) and that lesion is the lesion of many toxic and some metabolic diseases.
The first two slides came from a cow with oak poisoning. They could as well have been poisoning due to a number of other chemicals or toxic constituents. I would like you to think what they might be. The specks on the first one might be hemorrhages or casts of pigment, possibly hemoglobin, possibly tannic acid. It makes little difference whether we were looking at the kidney of a cow or a sheep or a dog or a hog or a horse or whatever. The chief issue in these three slides is a process. A process resulting in acute tubular necrosis and the realization that that lesion occurs with a number of poisonings in certain shock states and situations with severe burns, incompatible blood transfusions and a number of other states. Why don't you check up on that?
Key observations are: paleness, swelling ±, moistness, accentuation of cortical striation, AND evidence of renal failure (carcass odor, stomach odor, dilute urine, upper alimentary erosion).
Causes -- oak, amaranthus, mercury, amino glycosides, oxalate, etc., etc.
