Hydronephrosis is when there is “stretching” or dilation in the kidney where urine collects. It may occur in one or both kidneys. This dilation may be caused by a blockage (obstruction), vesicoureteral reflux (VUR) or for no obvious reason. This blockage occurs somewhere along the urinary system. This causes the urine to become trapped and the kidney to dilate. Vesicoureteral reflux is when the urine travels backwards into the kidney causing the dilation. Many times, children who have hydronephrosis are born with it. Sometimes it is unknown why babies develop hydronephrosis.
Hydronephrosis is graded on a four point system and is classified by the amount of dilation within the kidney. The grade of hydronephrosis depends on the amount of dilation, number of calyces (small collecting cups within the kidney) seen and the presence and severity of kidney tissue thinning. This is seen by ultrasound imaging.
Grading of Hydronephrosis:
Grade 1: mild “stretching” or dilation of the renal pelvis (where urine collects and drains to the bladder) only
Grade 2: moderate “stretching” or dilatation of renal pelvis including a few calyces
Grade 3: “stretching” or dilatation of the renal pelvis, seeing all the calyces, which are uniformly “stretched” or dilated, and normal kidney tissue
Grade 4: “stretching” or dilatation of the renal pelvis, seeing all of the calyces, and thinning of the kidney tissue
Diagnosis
Hydronephrosis is diagnosed by ultrasound. It may also be found with other image testing during an evaluation for other symptoms. Often children may have no symptoms. Some patients with severe hydronephrosis and have a blockage may have kidney pain, vomiting and urinary tract infections.
Treatment
Hydronephrosis is carefully monitored with periodic ultrasound imaging of your child’s kidneys. How often your child has ultrasounds will depend on several factors and will be determined by your provider. Your provider may order further tests. This may include a voiding cystourethrogram (VCUG) or kidney scans. If your child’s hydronephrosis is caused by a blockage, your child may need surgery. This will be discussed with you by your provider.
hydronephrosis grading
