EARLY CHANGES IN SERUM CREATININE AFTER UNILATERAL NEPHRECTOMY

Abstract

We studied early changes in serum creatinine of 134 nephrectomized cases (81 males, 53 females, mean age 52.1 y. o.) in 8 years. Underlying diseases resulting in nephrectomy were renal tumor (45.5%), renal pelvic or ureteral tumor (23.1%), renal dysplasia or hypoplasia (9.0%). There was one case of solitary kidney with renal tumor, which was excluded from this study. Of the other 133 cases, 16 cases (12%) showed increased serum creatinine concentration (Scr) over 2.0mg/dl and 8 cases over 3.0mg/dl after unilateral nephrectomy. Hemodialysis was necessary in 3 cases (2.2%).
In the 16 cases of decreased renal function, 14 cases were male and renal tumor was the most frequent cause of nephrectomy. In considering the risk factors, cases of decreased renal function showed older ages at operation and higher rates of concomitant hypertension, heart disease or diabetics than unchanged cases. The mean Scr before operation was 1.40mg/kg in the impaired group, which was slightly higher than the value in the unchanged group (1.16mg/dl), but not significantly different. At operation, operation time, bleeding and episode of hypotension were higher in the impaired group than in the unchanged group.
In the impaired group, there were 4 patterns of changes in Scr after unilateral nephrectomy. A) Scr rose in straight line immediately after nephrectomy and resulted in hemodialysis in one cases. B) In 6 cases, Scr increased gradually until about 4 days after operation and decreased thereafter. c) in 7 cases, Scr rose only on the next post-operative day and improved soon. D) There was delayed appearance of high Scr after about one week in 2 cases.
Because daily changes of Scr are calculable according to the following formula, Scr=(SynCr-Ccr×Scr)/(B. W.×0.6+Ccr), causes of decreased renal function may be predictable. The increases of Scr in a straight line immediately after unilateral nephrectomy means anephric state, which reflects severe renal functional impairment of the residual kidney. Kidneys with organic changes preoperatively with or without trouble at operation showed gradual increase in Scr for several days and gradual improvement thereafter. On the contrary, healthy residual kidney showed only transient rise of Scr after circulatory disturbance at operation. The increase in Scr after several days of normal values might be related to other causes such as heart failure or drug intoxication.
The result of our study indicates that, damaged kidney may not show compensatory changes or hypertrophy immediately after unilateral nephrectomy, usually observed in healthy residues. Special care must be taken for such cases.