Shock Kidney

A comparison of morphometric studies on autopsy kidneys and biopsies of kidneys from patients with acute renal failure (ARF) showed the following: Kidneys from patients who developed ARF a few days or weeks before death, are larger at post-mortem examination than kidneys from patients with normal renal function at death, because of an increased fluid content. In most cases the lumina of the proximal tubules are widened, with the relative epithelial area of the proximal tubules being statistically significantly smaller. Kidneys with normal function at death show a narrowing of the proximal tubular lumen at autopsy.The epithelial area of the proximal tubules is statistically significantly larger than that of biopsy kidneys with normal function. We conclude that in kidneys with normal function at death and in those that developed ARF before death, different structural changes appear which must be taken into account when correlating structure and function: In kidneys with normal function at death, the epithelial cells of the proximal tubules, in particular, swell because of fluid uptake from the tubular lumen.The fluid cannot recirculate in the intertubular capillaries because of stagnation of the circulation.In kidneys of patients with ARF, the tubular epithelial cells are markedly swollen during life.Fluid uptake does not occur after death, however; fluid escapes into the tubular lumen and into the renal interstitium, resulting in a widening of the lumina of the proximal tubules.Occasionally an interstitial edema is also seen at autopsy. Necrosis of the tubular epithelial cells and rupture of the basement membranes are very rarely observed in ARF.In addition to swelling of the epithelial cells, one may also see interstitial edema in ARF in biopsy.A statistically significant positive correlation exists between the degree of this interstitial edema and the most recent available serum creatinine concentration (during about 19.7 weeks).Thus, the broader the interstitium at the time of biopsy, the worse the prognosis concerning functional recovery because of development of a varying degree of interstitial fibrosis.