What is Hydronephrosis?

Hydros means water and nephros refers to the kidney. Hydronephrosis implies that the kidney is full of water (urine). Te more accurate description would be an enlargement of the collecting system of the kidney. The collecting system is that part of the kidney through which the urine that has formed is transported into the ureters.

Hydronephrosis can be due to obstruction to the flow of urine, or urine refluxing from the bladder back into the kidney, or neither.

Can Hydronephrosis cause a problem?

Yes it can. The kidney is more prone to infection. There can be other symptoms like pain. Also, a very tense Hydronephrosis can exert pressure on that part of the kidney that is responsible for urine formation. This may affect the function of the kidney.

Fortunately, today most children with Hydronephrosis are detected before birth by Ultrasound scans. This allows assessment and treatment to begin as soon as possible, before problems occur.

What needs to be done?

All children with Hydronephrosis need tests to find out how severe the problem is. The usual tests are testing the blood and urine, and visualizing the swelling by ultrasound scans. Finally a radionuclear scan is performed. This gives important information about how much the function of the kidney has been affected. Based on all these, a doctor can decide whether Hydronephrosis needs surgical correction or not.

If a Hydronephrosis does not warrant surgery immediately, some tests may be recommended every three to six months, or every year, to make sure that the kidneys are not swelling more, and that they continue to function well.

An Xray showing a blocked kidney with Hydronephrosis on one side (red arrow), and a normal kidney on the other side (blue arrow). Here the ureter is clearly seen (green arrow), going down to the urinary bladder (yellow dot)