Last Updated : 1/14/2010
Kumud P Mehta


(HDN) is defined as dilatation of renal pelvis and calyceal system. Hydronephrosis can be unilateral or bilateral, obstructive or non-obstructive; congenital or acquired. Hydronephrosis in fetus/newborn is increasingly recognised due to widespread use of fetal ultrasound scanning, advanced USG equipment and greater expertise. It is estimated that urinary tract dilatation in utero is identified in 1% all pregnancies but in only 1/5th of these, the abnormality is significant. The best method of diagnosing HDN is by USG of kidneys ureters and urinary bladder, so that the cause of HDN can be detected.

Common causes of hydronephrosis
- Pelviureteric junction obstruction (PUJ obstruction)

Vesicoureteric reflux (VUR)

- Vesicoureteric junction obstruction

Multicystic kidney

- Posterior ureteric valves (PU valves) (can be bilateral)
- Obstructive or non obstructive megaureters
- Ureterocele

Neurogenic bladder

- Prune belly syndrome

Urethral atresia

Acquired hydronephrosis
Hydronephrosis can occur due to

acquired causes


Urolithiasis or stone disease


Stricture of ureter due to tuberculosis or following urologic surgery.

The underlying cause should be treated, obstruction removed by ESWL or surgery. Kidney can be permanently damaged because of pus formation in an obstructed hydronephrotic kidney due to pyonephrosis.

Contributor Information and Disclosures

Kumud P Mehta
Consultant Pediatrician & Pediatric Nephrologist, Jaslok Hospital & Research Centre, Bai Jerbai Wadia Hospital for children, Mumbai, India

First Created : 1/10/2001


Disclaimer: The information given by www.pediatriconcall.com is provided by medical and paramedical & Health providers voluntarily for display & is meant only for informational purpose. The site does not guarantee the accuracy or authenticity of the information. Use of any information is solely at the user's own risk. The appearance of advertisement or product information in the various section in the website does not constitute an endorsement or approval by Pediatric Oncall of the quality or value of the said product or of claims made by its manufacturer.