单侧肾盂输尿管连接部梗阻患儿分肾功能"超正常"现象及其临床意义

"Supra-normal" phenomenon of differential renal function in children with unilateral ureteropelvic junction obstruction and its clinical significance

目的分析单侧肾盂输尿管连接部梗阻(ureteropelvic junction obstruction,UPJO)致肾积水患儿中分肾功能(differential renal function, DRF)出现"超正常"现象(DRF>55%)者的特征及其临床意义。方法回顾性分析上海交通大学医学院附属上海儿童医学中心2014年1月至2017年5月间收治的单侧UPJO致肾积水患儿中患肾出现DRF"超正常"13例的临床资料。其中,男11例,女2例;平均手术年龄15.4个月;左侧12例,右侧1例。患儿术前常规行血尿常规、肝肾功能及泌尿系超声及同位素利尿肾图检查,归纳总结其存在的临床症状及影像学异常等检查结果。结果13例DRF"超正常"患儿术中均证实为UPJO。其中有7例患儿为孕期体检发现的肾积水;超声检查提示术前平均肾盂前后径为35.5 mm,肾皮质平均厚度为3.7 mm。同位素利尿肾图检查提示平均DRF为57%,所有患儿T1/2均大于20 min。所有患儿均在术后6个月复查同位素利尿肾图,10例(76.9%)患儿DRF较术前下降>5%;2例患儿DRF无明显变化;1例患儿术后肾积水复发。结论DRF"超正常"现象不一定是真正的肾功能升高,可能是梗阻性肾高滤过状态的表现。诊治过程中尽量通过结合一系列的症状、体征、超声及MRI等影像检查作出UPJO的明确诊断,进而制定个体化的治疗方案,能够获得满意的治疗效果。DRF"超正常"现象发生的确切机制需要进一步的实验研究来明确。

Objective Ureteropelvic junction obstruction (UPJO) is a common cause of hydronephrosis in children. A reduction of renal function is an important feature of kidney. Occasionally hydronephrotic kidney has higher than "normal" differential renal function (DRF). Whenever DRF exceeds 55%, it is regarded as a "supra-normal" phenomenon. The clinical, imaging and prognostic characteristics of children (received pyeloplasty) with "supra-normal" differential renal function (SNDRF) were analyzed. Methods We searched for 13 SNDRF children (unilateral UPJO) undergoing pyeloplasty from January 2014 to May 2017. There were 11 boys and 2 girls with an average operative age of 15.4 months. The involved side was left (n=12) and right (n=1). All patients underwent routine liver and renal function tests, urine culture and urinary tract ultrasound. Their clinical data were collected and clinical symptoms and imaging abnormalities summarized. Results All of them were confirmed intraoperatively as UPJO. Among them, 7 cases of hydronephrosis were detected by physical examination during pregnancy. Ultrasound showed that the average preoperative pelvic diameter was 35.5 mm and the average thickness of renal cortex was 3.7 mm. Diuresis renogram (DR) showed that the average DRF was 57%. T1/2 was >20 min in all children. Re-examination of DR was made at 6 months post-operation. DRF had no significant change in 2 cases. There was one case of postoperative recurrence of hydronephrosis. Ten cases experienced >5% loss in function. Conclusions SNDRF may not reflect true elevated renal function, but rather hyperfiltration during obstruction. A definite diagnosis of UPJO is made by combining a series of symptoms, signs, ultrasound and magnetic resonance imaging (MRI) examination. And individualized treatment protocols may yield satisfactory therapeutic outcomes. The exact mechanism of SNDRF requires further experiments.