The clinical use of contrast media continue to increase at an enormous rate with new -development in diagnostic modalities.
Although reports of the contrast media used in roentgenography producing acute renal umpairment have increased, the pathogenesis is unclear. Predisposing factors include advanced age, previous renal insufficiency, diabetes mellitus, dehydration, multiple myeloma, ,cardiac disease and hyperuricemia.
The author emphasize recent information concerning the pathophysiology of nephrotoxic .acute renal impairment produced by radiocontrast media available nowadays and aminogly--coside antibiotics-Gentamycin, which administered subcutaneously twice daily for 10 days. 350 rats (Weight 180-2009m) classified into 3 groups, dehydrate group, hydrate group and ,Gentamycin induced renal impaired group. The author injected small dose, proper dose and massive dose respectively and then took IVY and enforced nephrectomy for histologic -examination whether tubular damages or not.
The results were summarized as follows:
1. Incidence of contrast induced nephrotoxicity.
1) Dehydrate group
Histologic changes developed in 29 rats among 125 rats with. overall incidence of 23.2% Ideal dose without nephrotoxicity ranges from 0.5ml to 1.5ml/kg.
2) Hydrate group
Histologic changes developed in 26 rats with overall incidence of 20.8%, lower than dehydrate group.
Ideal dose without nephrotoxicity ranges from 0.5ml to 1.5m1/kg.
3) Gentamycin treated group
Histologic changes developed in 37 rats among 80 rats with overall incidence of 46.3%.
13 rats died with dosage of 5.Oml/kg, motality rate of 52%. Proper dose range from 1.5ml
and under 2.5ml/kg.
2. Intravenous pyelography
1) Dehydrate group
All rats showed good nephrogram and pyelogram during 5 minutes to 30 minutes. No evidence of visualization of large intestine even after 12 hours or 24 hours.
2) Hydrate group
Good nephrogram and pyelograms were taken at 5 minutes to 30 minutes with dosage of 0.5m1 to 1.5ml/kg.
3) Gentamycin treated group
Poorly visualized nephrogram taken at 30 minutes to 60 minutes. 12hours delayed film showed contrast filled large intestine, possibly due to extrarenal excretion because of renal impairment.
3. Histologic findings.
There were variable findings including interstitial hemorrhage between renal cortex and medulla, eosinophilic proteinous round material in the distal convoluted tubules, hydropic degenera~on of proximal convoluted tubules and toxic necrosis of proximal convoluted tubules with focal degeneration.
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