Hydronephrosis (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
- Posterior ureteric valves (PU valves) (can be bilateral)
- Obstructive or non obstructive megaureters
- Prune belly syndrome
Acquired hydronephrosisHydronephrosis can occur due to
acquired causes like
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.