There are two types of vesicoureteral reflux, or VUR.

膀胱输尿管反流（VUR）有两种类型。

Vesicoureteral reflux is usually classified by severity - grade I through V, depending on how far urine refluxes back up into the urinary tract.

膀胱输尿管反流根据严重程度分为1-5级，严重程度依据尿液反流的程度进行衡量。

Vesicoureteral reflux can be diagnosed with an abdominal ultrasound, which can detect blockages in flow of urine and swelling in the ureters or kidneys.

膀胱输尿管反流可通过腹部超声检查确诊，可检测到尿液流动阻塞，以及输尿管和肾的肿胀。

Primary vesicoureteral reflux is usually due to a short ureter, while secondary vesicoureteral reflux is usually due to a blockage in the urinary tract.

原发性膀胱输尿管反流，多由于输尿管短小；而继发性膀胱输尿管反流，多由于尿路中存在阻塞。

Chronic vesicoureteral reflux can cause pyelonephritis, or inflammation of the kidney, and renal scarring, or fibrosis which damages the kidney tissue.

慢性膀胱输尿管反流可能导致肾盂肾炎，即肾脏出现炎症反应，以及瘢痕肾，即肾组织因纤维化而受损。

Risk factors include urinary tract infections, as well as vesicoureteral reflux and obstructive uropathies, both of which are also risk factors for urinary tract infections.

危险因素包括尿路感染，还有膀胱输尿管反流和尿路梗阻，这两者也是尿路感染的危险因素。

Secondary vesicoureteral reflux is most commonly caused by recurrent urinary tract infections, which can cause inflammation in the ureters making them swell up and close.

继发性膀胱输尿管反流，最常见于反复的尿路感染；炎症反应会引起输尿管肿胀和闭塞。

As a child grows, the ureter gets longer and the function of the valve improves, so primary vesicoureteral reflux sometimes improves or disappears over time.

随着婴幼儿的成长，输尿管变长，瓣膜的功能也有所改善，因此，原发性膀胱输尿管反流可能随时间改善，甚至消失。

Alright, as a quick recap, vesicoureteral reflux is a condition where pressure in the urinary outflow tract increases and urine gets pushed back up into the ureters or kidneys.

得！快速复习一下：膀胱输尿管反流是指一种由尿路压力增高导致尿液在压力作用下逆流至输尿管或肾的疾病。

In vesicoureteral reflux, there is some obstruction in that path which causes pressure to build up and a current of urine actually pushes backward from the bladder into the ureters and kidneys.

膀胱输尿管反流中，尿路存在阻碍，导致膀胱中压力升高，尿液受压从膀胱逆流至输尿管再到肾。

All right, as a quick recap: acute pyelonephritis is typically a bacterial infection of the upper urinary tract, which usually develops from a lower urinary tract infection, especially in individuals with vesicoureteral reflux.

得！快速回顾一下：急性肾盂肾炎是一种典型的上尿路细菌感染，通常由下尿路感染发展而来，尤其在膀胱输尿管反流患者中。