Hydronephrosis

Clinical picture

In this case, there is an obstruction to the outflow of urine at the transition from the renal pelvis to the ureter. This can be caused by a congenital narrowing in the ureter or by external compression (e.g. atypical vessel). Most ureteral outlet stenoses already have a conspicuous ultrasound before birth. If the dilation is pronounced, the constant build-up of urine can lead to long-term damage to the kidney tissue.

Symptoms

Infants and small children usually have no symptoms. Older children sometimes have flank pain or suffer from urinary tract infections.

Diagnosis

The diagnosis is made using ultrasound and is confirmed at our centre using MAG3 scintigraphy. This uses a specific substance (mercaptoacetyltriglycine), which is administered via the vein and only excreted in the body via the kidney, to measure the rate of urine flow from the kidney into the ureter. This helps to determine whether or not there is a relevant anatomical obstruction to the outflow of urine.

Therapy

If there is a relevant outflow obstruction, an operation is recommended. This involves removing the obstruction and reconnecting the ureter to the renal pelvis. This is performed at the UKBB as standard using laparoscopic surgical techniques (minimally invasive, camera method).

Clinical picture

Vesicoureteral reflux is the second most common cause of renal pelvic caliceal dilatation in infants. This means that urine from the bladder flows back into the kidney via the ureter. Normally, a kind of valve mechanism prevents the urine from flowing back.

Symptoms

In the congenital form, primary VUR, there is an imbalance in the area of the ureteral orifice in the bladder wall after birth, which causes the reflux. With increasing maturity and growth, VUR very often heals spontaneously. Secondary VUR is an acquired form and occurs as a result of other malformations/diseases (urethral stricture, neurological bladder diseases, bladder dysfunction). There are various degrees of severity of VUR, which are categorised into five levels.

Diagnosis

If urinary tract infections occur more frequently, further diagnostics should be carried out using ultrasound and MCUG (micturition cystoureterography). This is carried out by the radiology department at UKBB. We discuss the procedure and the examination steps with the parents during our consultation hours.

Therapy

Treatment depends on the severity of the VUR, the ultrasound findings, the course of the disease and the patient's age. Antibiotic prophylaxis is recommended for more severe VUR in order to prevent urinary tract infections and thus potential kidney damage. This "bridges" the time until spontaneous healing. According to the latest findings, regular defecation and regular urination are of great importance for successful treatment. Occasionally, surgical treatment is required to eliminate the VUR. In this case, we offer minimally invasive injections in the bladder at the ureteral orifice. In complex cases, a new ureteral implantation is sometimes necessary.

Clinical picture

In addition to dilation of the renal pelvis, the ureter can also be dilated to varying degrees. In addition to VUR (see above), the cause may be a narrowing at the transition to the bladder (obstructive megaureter) or simply a urinary transport disorder. If there is a constriction at the entrance to the bladder, the urine backs up into the kidney.

Symptoms

In most cases, the children have no symptoms, but occasionally urinary tract infections occur. Here too, spontaneous healing can often be seen in the first year of life.

Therapy

If a relevant constriction persists or the dilation continues to increase, surgery is necessary to prevent long-term kidney damage.

Clinical picture

With urethral valves, there is a constriction in the urethra shortly after the bladder outlet due to a type of tissue sail. This causes high pressure to build up when urinating, which can be channelled into the kidneys. This can have serious consequences for the urinary system (kidneys, ureters, bladder), which is why early diagnosis is important.

Symptoms

Despite early treatment, kidney damage occurs in 25-50 % children. Bladder emptying disorders are also common.

Diagnosis

Ultrasound typically reveals a thickened bladder wall and dilation of the renal pelvic caliceal system and ureters of varying degrees of severity. These are often already visible during pregnancy. However, in some children the urethral valves only become apparent in the course of later childhood or puberty due to problems urinating or becoming dry. An MCUG (micturating cystoureterography) is necessary for a more precise diagnosis.

Therapy

The treatment consists of urethral and bladder endoscopy with slitting or removal of the valves. For this operation, we plan a hospitalisation of two to three days, as a catheter is temporarily inserted into the bladder to splint the urethra.

• Neonatal hydronephrosis: recommendations for care in French-speaking Switzerland, Paediatrica, Vol 21. 2010H. Chehade, P. Parvex, F. Cachat, J-B Meyrat, J. Birraux, P. et al.
• PaediatricUrologyGuidelines 2022; European Association of Urology, C. Radmayr et al.