Hydronephrosis affects the urinary system and results in urine retention. This disease is painful but can be treated with a small surgical operation when it is due to a deformity.

Hydronephrosis is a disease that affects the urinary tract. It is the consequence of urine retention due to a narrowing or obstruction of the ureter (conduit that carries urine to the bladder). This results in an increase in volume of the pelvis, calyxes and the affected kidney. 

The possible causes of hydronephrosis are:

• The muscles inside the ureters are immature
• Reflux (urine going up to the kidneys)
• Blockage in the kidney, bladder or urethra
• A congenital malformation of the junction of the pelvis and urethra
• Urinary obstructive disease (tuberculosis, calculus, tumor of the ureter)
• A double ureter
• Cysts in the kidney
• Pregnancy causing the uterus to push against and block the tubes connecting the bladder and kidneys. Hydronephrosis during pregnancy is not unusual.
• An enlarged prostate gland surrounding the urethra between the bladder and the penis, which can occur as you age. This can compress and obstruct the urethra.
• Certain cancers affecting the urinary system. These include cancer of the kidney, prostate, bladder, cervix, or ovary. If a tumor puts pressure on part of the urinary system, it can obstruct the flow of urine from the kidneys.

An ultrasound of the kidney and an intravenous urography make it possible to visualize the dilation of the urethra as well as the location and nature of the obstacle, if there is any.

Hydronephrosis is very common. About 1 in 100 babies are born with hydronephrosis. For about half of these babies, the problem goes away before the child is 2 years old.

The main symptoms of hydronephrosis are:

• Renal colic: great back pain
• Kidney pain
• urinate less often or not as heavily
• blood in urine
• any symptoms of a UTI, such as painful urination, cloudy urine, and a strong urge to urinate
• fever
• nausea and vomiting

If hydronephrosis is not treated, complications may appear:

• Risk of renal failure.
• Polyuria: secretion of urine in copious amounts, which is an increase in urine volume above 500 ml per day.
• Nocturia: urination during the night.

Treatment will depend on the cause of the hydronephrosis.

If the urethra is blocked, the patient will need to undergo a small surgery to unblock the passage of urine. In the case of chronic hydronephrosis, an operation may be scheduled to remove the part of the urethra containing the malformation. Endoscopic surgery also makes it possible to remove a congenital stenosis by simple incision or dilation. After treatment for a birth defect, a ureteral calibration catheter is left in place for a few weeks.

If the patient has reflux, they may take antibiotics to prevent infection until the syndrome improves or is corrected.

Hydronephrosis caused by pregnancy usually goes away without treatment after pregnancy ends.

Hydronephrosis is mainly caused by a birth defect. It is then impossible to prevent the symptoms. 

Drinking in sufficient quantity helps the kidneys to function properly and reduces the risk of hydronephrosis.