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Vur causes and Diagnosis or causes and Diagnosis of Vur

Urinary reflux or Vesico Ureteric Reflux (VUR) is a condition in which there is a back flow of urine in the bladder through the junction between the ureter and the bladder wall, towards the kidneys. The reflux usually occurs when the bladder wall contracts at the time of passing of urine or at times of filling the bladder.

Persistent VUR can lead to permanent renal damage and related complications which at its late stage would be irreversible. In most instances, the condition is diagnosed in the childhood and timely intervention can prevent further complications associated with the condition.

There are several causes identified as contributing to the occurrence of a VUR. Some of these causes can be present from birth and is known as primary cause and some are secondary to certain disease processes.

Out of the primary causes, following are very significant.

1. Shortened ureter

The distal end of the ureter enters the bladder wall and traverses several layers obliquely before draining into the bladder lumen. The muscle layers will act as a ‘flap valve’ and while promoting the passage of urine towards the bladder lumen it prevents the backflow of the urine back up the ureter. When the intra-mural portion of the ureter is absent or is short, the bladder wall will be ineffective in its valve mechanism. Thus, it will allow VUR to take place.

2. Abnormal placement of the vesico-ureteric junction

Usually, the ureter enters the bladder at the region of the trigone of the bladder and any other positioning can result in abnormal flap valve mechanism and thus retrograde flow of the urine.

3. Abnormal ureteric orifice

Certain abnormalities detected at the opening into the bladder will also lead to abnormal valve mechanism.

4. Poor muscle support

The contraction and the thinning out of the bladder muscles controls the flow in the intra-mural part of the ureter and any abnormal functioning or support by the bladder muscles will allow the urine to flow backwards and towards the kidney.

When considering the secondary causes for the VUR, following are identified as important,

1. Urinary Tract Infections

2. Cystitis

Both these infections are able to precipitate VUR and the infection itself might be the result of an existing VUR. Thus, it seems to act as a vicious cycle and unless stopped at one point, it can lead to more disruptive consequences.

3. Urethral obstruction

Outflow obstruction is a common cause of VUR. Posterior urethral valve in a male infants as well as prostate enlargement can result in a VUR unless treated at the right time.

4. Bladder muscle instability

The instability will lead to poor control of the valve mechanism and thus retrograde urine flow through the ureter.

Apart from the above mentioned causes, there are many other instances where the VUR is a being identified.

The presentation of VUR could be either as a urinary infection, high blood pressure, poor urine flow, facial and body swelling or related symptoms. Thus, such symptoms would warrant following investigations to correctly identify a VUR.

1. Ultrasound Scan of the kidney, ureter and bladder

This will be the first instance a VUR could be identified and in certain instances it can miss a mild reflux. Abnormalities in the kidneys can also be detected through this test and with correlation of the history and other investigations can suggest the presence of a VUR.

2. DMSA Scan

The scan will be done in order to identify renal scarring following a febrile urinary tract infection and the presence of such scarring will lead to a possibility and further assessment for the presence of a VUR.


Voiding Cysto Urethrogram is a radiological test in which a contrasting dye instilled into the bladder will flow back into the ureter and towards the kidneys at times of voiding in the presence of a VUR.

Following these tests, an exact diagnosis of a VUR would be possible and it can influence the management decision taken by the clinicians.