Ques 1 What is Hydronephrosis?
Ans. Hydronephrosis is a condition, affecting about 1 in 100 babies, where urine overfills or backs up into the kidney, causing the kidney to swell. Infants with hydronephrosis may be diagnosed before (prenatal) or after (postnatal) birth.
Ques 2 What are the Symptoms of Hydronephrosis?
Ans Hydronephrosis symptoms aren’t usually obvious, so the condition is usually detected during investigations that are being done for other reasons. When hydronephrosis occurs in the womb, it is often detected during the routine anomaly scan that is performed at around 20 weeks. Hydronephrosis symptoms can also be detected in babies after the birth if doctors are performing scans to investigate the causes of urinary symptoms.
Most children do not present with any signs or symptoms for unilateral hydronephrosis. Historically the most common symptom for hydronephrosis is in fact a urinary tract infection. The symptoms of urinary tract infection in the older child can consist of high temperature, pyrexia and dysuria (pain when voiding). There could be cloudy urine, blood in the urine and pain in the child’s side or their back. Younger babies will not necessarily present with clear symptoms and when they develop a urinary tract infection they can have high temperature, irritability and failure to thrive.
Presently a vast majority of children are diagnosed with hydronephrosis on fetal scans. At present, the 20 weeks scan can be useful for detecting hydronephrosis and this frequently means there may be further ultrasound scans required in pregnancy. This can occur at approximately 1 – 2% of all pregnancies.
In the occasion of unilateral hydronephrosis, the baby will require an ultrasound scan after the child is born.
It is important for hydronephrosis symptoms to be investigated carefully in order to identify the cause of the problem. Untreated hydronephrosis could increase the risk of urinary tract infections and it might affect the functioning of the kidneys. The kidneys could be damaged if the problem is left untreated.
Ques 3 What are the Causes of Hydronephrosis?
Ans Hydronephrosis happens when urine collects inside the kidneys. The kidney will then swell up. The increase in size can be detected on an ultrasound scan. Urine can build up inside the kidney if it isn’t able to make its way to the bladder or if it returns back up the ureter.
Hydronephrosis can happen for a number of different reasons. In most cases, the problem will only affect one of the kidneys. This is known as unilateral hydronephrosis and it won’t usually cause serious issues as the unaffected kidney will still be able to function normally.
The most likely causes of hydronephrosis in babies are:
- Blockages in the urinary tract. The blockage could be between the kidney and ureter, between the bladder and the ureter or in the urethra that leads out of the bladder.
- Ureteric duplication, which happens when there are two ureters connecting one of the kidneys to the bladder. The lower end of one of these ureters is then likely to be blocked. This condition happens in about 1% of babies.
- Multicystic dysplastic kidney (MCDK), which occurs when one of the kidneys fails to form correctly. The non-functioning kidney contains large numbers of cysts.
- Vesico-ureteric reflux (VUR), which occurs when the valve where the ureter connects to the bladder doesn’t work properly. It isn’t able to stop urine from moving back up the ureter towards the kidney.
Ques 4 How the Surgery of Hydronephrosis diagnosed?
Ans Hydronephrosis can be diagnosed using ultrasound scans to check for kidney enlargement and MAG3 scans to get more detailed pictures of the kidneys.
Depending on the ultrasound scan and MAG3 findings and their symptoms, some children will require surgery to improve drainage of their kidney This is an operation to remove the small narrowed area between the pelvis of the kidney and the ureter which is called the pelvi ureteric junction (PUJ). Once this is removed, two tubes are joined back together and a small stent is left internally. This is removed a number of months later.