Hirohisa Kitada

Regression of acquired cystic disease of the kidney after successful renal transplantation

The effect of renal transplantation on acquired cystic disease of the kidney in patients who have been on hemodialysis for more than 5 years was examined in 7 cases by computer-assisted tomography (CT scan). Almost all acquired cysts disappeared, and the size of the original kidneys decreased remarkably in 2 cases 8--10 months after transplantation. 3 other patients, in whom CT scans were performed only after transplantation, showed contracted scarred kidneys with few or no cysts. The involution of acquired cysts was incomplete in 1 case, in whom the cysts persisted for 3 years and 2 months, despite normal renal function. The last case, who was off hemodialysis only for 4 months, exhibited enlargement of the original kidneys and an increase in the number of cysts. These results suggest that a significant number of acquired renal cysts in dialyzed patients with end-stage kidney disease regress rapidly after successful renal transplantation, but this is not always so.

Ten-Year Prospective Study on the Development of Renal Cell Carcinoma in Dialysis Patients

A prospective study was undertaken to investigate the development of renal cell carcinoma in dialysis patients. Three renal cell carcinomas were detected among 96 hemodialysis patients in 1979, and screening by computed tomographic (CT) scan was continued yearly until 1989. During this 10-year period, one renal cell carcinoma was found in the second year and another in the ninth year. Autopsy performed on seven of 19 patients who died showed one case of small clear cell carcinoma accompanying acquired cystic disease. In 33 males, kidneys were found to have enlarged 2.7 +/- 1.7 times over the 10-year follow-up due to acquired cysts, while no change in kidney volume was noted in 24 females. Native kidneys in nine of 12 patients who maintained functioning grafts were reduced in size. The patient with the largest kidney enlargement (11.5 times) died from retroperitoneal bleeding in 1989. These prospective study results suggest that both the incidence and prevalence of renal cell carcinoma in dialysis patients is high. Furthermore, major complications of acquired renal cystic disease seem to occur predominantly in males.

Sex differences in acquired cystic disease of the kidney on long-term dialysis.

Acquired cystic disease of the kidney in chronic glomerulonephritic patients who had been on hemodialysis more than 3 years (4.5 +/- 1.2 years at the base line examination), were followed for 3.6 +/- 0.5 years (at the follow-up examination) by computed tomography (CT scan). The renal volume in the 25 male patients was significantly greater at the follow-up examination than at the base line examination. On the other hand, the renal volume in the 12 female patients was similar on both examinations. The enlargement of kidney volume more than twofold during the follow-up was seen in 9 of 25 male and none of 12 female patients. The grade of cystic transformation was increased in male patients during the follow-up period. These results indicate that sex-related endogenous substances might play a role in the pathogenesis of acquired cystic disease.

Renal cortex visualization and analysis of dynamic CT curves of the kidney.

Renal cortex visualization and dynamic renal computed tomography (CT) were carried out by bolus injection of contrast medium. In vivo renal cortex visualization showed that renal cortex volume and cortex thickness are both inversely correlated with age. The percentage volumes of cortex and columns of Bertin are correlated inversely in non renal-failure subjects. Percentage volumes of cortex tend toward low values in renal failure and status after renal transplantation. In analyzing dynamic renal CT curves, the corticomedullary junction time is a good index of mild impairment of renal function.

ACQUIRED CYSTIC DISEASE OF THE KIDNEY AND RENAL CELL CARCINOMA ON LONG TERM HEMODIALYSIS

Four surgical cases of acquired cystic disease of the kidney in the third decade are reported, which include renal cell carcinoma in three patients and multiple adenomas and cystadenomas in all patients. The intervening parenchyma of these kidneys was disorganized as end stage kidney and numerous cysts were found in both kidneys. Some of the cysts were lined by hyperplastic epithelium consisting of clear and granular cells arranged in piled up and papillary fashion. These cysts were diagnosed as cystadenoma. Multiple solid adenomas of a 28‐year‐old male on hemodialysis for 6 years were of various size as if arranged in developing stage of the growth. Summing up all cases included in the literature, the mean duration of hemodialysis of the cases with renal tumor was 5.2 years, while 2.9 years without tumor. With increase of duration of hemodialysis, acquired cystic disease of the kidney is exposed to a high risk of developing malignancy.

Severity of Acquired Renal Cysts in Native Kidneys and Renal Allograft With Long-Standing Poor Function

To identify factors related to the development of uremic acquired cystic disease of the kidney, native and grafted kidneys were examined in four men and three women after kidney transplantation. The incidence and severity of cystic transformation of native kidneys and grafts were compared by plain computed tomographic scans. In a uremic environment (serum creatinine level of greater than or equal to 265 mumol/L [3 mg/dL] for an average of 5.0 years; range, 2.8 to 8.2 years), acquired renal cysts were formed in both the native kidneys and the graft in three of the male and one of the female patients. Cysts were extensive in the native kidneys but relatively infrequent in the grafts in three of the men. One male subject was found to have acquired cysts only in the native kidney. Acquired renal cysts developed even in grafts undergoing chronic rejection, and increased numbers were found in native kidneys that were in uremic conditions for long periods, both before and after renal transplantation. These results suggest that the duration of uremia is the most important factor in the development of acquired renal cysts.

Dynamic computed tomography in acute renal failure: analysis of time-density curve.

An analysis of dynamic CT curves in 12 patients with acute renal failure was performed. An oliguric patient who demonstrates corticomedullary differentiation on CT images will develop diuresis within 4 days. A corti-coaortic junction time of more than 180 s associated with no differentiation between cortex and medulla is associated with prolonged oligoanuria. Impending diuresis is heralded by a corticoaortic junction time of less than 180 s. These preliminary results suggest that an analysis of dynamic CT curves in acute renal failure can predict the time of appearance of the diuretic stage.

Regression of Adult Type Polycystic Kidneys during Chronic Intermittent Hemodialysis. Is It a Universal Phenomenon

Isao Ishikawa, MD, Division of Nephrology, Department of Internal Medicine, Kanazawa Medical University, Uchinada, Kahoku, Ishikawa 920-02 (Japan) Dear Sir, We followed the size of 9 polycystic kidneys in 5 patients using CT scan [1] from 23 to 52 months (36.8 ± 4.9 months; mean ± SEM). Chronic hemodialysis was performed for 5–6 h 3 times a week. 1 case was nephrecto-mized before the induction of hemodialysis because of traumatic rupture of the cysts. As shown in figure 1, 2 kidneys increased in size, 5 remained unchanged (within 10% change of size), and 2 decreased in size. These results do not agree with the observation by Thaysen and Thomsen [2] that polycystic kidneys underwent involution during replacement therapy and that the degree of involution did not appear to depend on the replacement therapy method (i.e. hemodialysis or renal transplantation). 1 of their 12 patients was maintained with hemodialysis only. 5 others had a longer duration of dialysis than transplantation. However, 3 of the 5 were alive on graft at the time of their study.

Asymmetric hypertrophy of renal graft after transplantation.

Isao Ishikawa, MD, Division of Nephrology, Department of Internal Medicine, Kanazawa Medical University, Uchinada, Kahoku, Ishikawa 920-02 (Japan) Since the cortical thickness of the graft is thinner at contact with the psoas muscle [1], it is suggested that the local mechanical effect of the recipient affects the graft hypertrophy, i.e. the upper part of the graft facing the upper abdomen hypertrophies more than the lower part facing the minor pelvis where there is no space to move. In order to prove this hypothesis, renal volume was measured using CT scan in its upper, hilar and lower parts. Six recipients (25.3 ± 7.9 years of age, mean ± SD) received grafts from their parents (53.2 ± 5.6 years of age). CT scans were performed from the upper pole to lower pole of the kidney sequentially with a constant slice width (8 mm), 77 ± 43 days before transplantation and 75 ± 28 days after transplantation for grafts and 42 ± 36 days after transplantation for donor’s remaining kidneys. The donor’s left kidney was transplanted in the right iliac fossa of the recipient inside out. The serum creatinine levels in 6 recipients were 1.0–1.5 mg/dl at the time of CT examination after transplantation. The upper or lower parts of the kidney were defined as kidney part above the uppermost scan level or below the lowest scan level where the hilus is included. The hilar part was defined as the renal part with scan slices including the renal hilus. The volumes of the upper, hilar and lower parts were measured in 35 recipients who received the donor’s left kidney in their right iliac fossa besides 6 donor and recipient pairs. The angle of the axis of the graft to the median line in 6 recipients (1.2 ± 5.7°) is significantly more upright than the axis of the left kidney in the donor (-12.4 ± 7.6°) (p < 0.05). Therefore, the volume of the upper part of the graft is underestimated and the volume of the lower part is overestimated because the axis of the graft is more upright.

Blood pressure changes and renal transplantation

腎移植前の血液透析療法時の血圧と術後の血圧の関連, およびこれに関与する因子について検討した. 1975年3月以降生体腎移植を受け, 2ヵ月以上生着して3年間経過を観察し得た72例を対象とした. 術前の週3回の人院透析中は30例 (42%) に高血圧が, 8例 (11%) に低血圧をみられた. 腎移植後は48例 (67%) に高血圧が出現したが, 術前高血圧があった例は術後もひき続き高血圧を示すことが多かった. 急性拒絶反応のepisodeが0-1回と2回以上では2回以上に有意に高血圧が多く, また慢性拒絶反応がみられたものは3例を除き18例が高血圧を呈した.腎移植前の血漿レニン活性 (PRA) と移植後の血圧の間には関連がなかったが, 移植後高血圧のある群はないものよりPRAが高値を示した. 少数例での分腎レニン活性測定ではすべて原病腎からのPRAは移植腎のそれを上回り, 原病腎からのレニン分泌増加を示唆した.移植後腎動脈狭窄で治療を要したものは1例のみであった. 移植後の高血圧は難治例が少なく, 約2/3の症例が2剤以内の降圧薬でよくコントロールされた.移植前に低血圧を示した例が8例あり, うち4例は両側腎摘除を受けていた. 5例に術後, 乏尿性急性腎不全が起きたが, 8例とも手術の翌日には血圧が正常化していた.以上より, 高血圧は腎移植後の頻度の高い合併症であり, その原因としては術前の高血圧の持続と慢性拒絶反応が重要である. 術前より高血圧が持続する例ではレニン分泌過剰が主要機序と考えられる. 術前の低血圧はとくに無腎例に多くみられ, 腎移植により速やかに正常化し, その過程よりみて健常腎組織に関連する体液性因子の関与が考えられる.