Urinary system birth defects

The urinary system consists of the kidneys, ureters, bladder and urethra. The human body typically has two kidneys (one on either side of the middle back) that filter wastes from the blood and produce urine. Each kidney has a tube called a ureter. Urine leaves the kidneys via the ureters and enters the bladder for temporary storage. The urethra is a tube that connects the bladder to the outside of the body, allowing urine to exit. Common congenital variations of the urinary system include hypospadias, obstruction of the renal pelvis and renal agenesis.

Hypospadias

Hypospadias is a genital variation of the penis that most times has the following associations:

• The urethral opening is located on the underside of the penis, instead of the tip, and may exit the penis anywhere along its shaft as proximal as the base of the scrotum.
• Hooded foreskin: the foreskin is not closed on the underside of the penis
• Ventral penile curvature, also known as “chordee”

Hypospadias is one of the most common genital variations in Victoria, occurring in around one in 150 births. Most often, hypospadias is noticed at birth; however, if the hypospadias is particularly mild, diagnosis may come later in life.

Causes of hypospadias

The causes of hypospadias are unknown. There seems to be a genetic association, since a baby boy with a family history of hypospadias is slightly more likely to be born with the condition.

Hypospadias care

Hypospadias does not require urgent surgical intervention. In severe cases or when a hypospadias is associated with an undescended testis, it is important to perform further diagnostic testing to determine if there are any other related issues. Psychosocial support to normalise genital variations is beneficial.
Hypospadias surgery is most commonly performed between 6 and 18 months of age.

The aims of surgery include repositioning the urethral opening at the tip of the penis, straightening the penis (if chordee is present). Repositioning the urethral opening is relatively straightforward and can be performed in a single stage in mild cases. In more severe cases, a 2 stage procedure is the best option. A skin graft using the foreskin may be needed. It is important not to have your son circumcised before the hypospadias surgery, in case the foreskin is needed.

In mild cases, the foreskin can either be reconstructed or the end result be of a circumcised penis. This is according to the parent’s preference

Obstructive anomalies of the renal pelvis

An obstruction of the renal pelvis means that urine can't drain properly from the kidneys into the bladder. One or both ureters may be affected. this can produce severe dilatation of the kidneys and, without treatment, can lead to urinary tract infections and kidney damage. This condition occurs in around one in 350 Victorian babies. Symptoms include recurrent urinary tract infections and may also include impaired growth. Other names for this condition include uteropelvic junction obstruction and pelvi-utereric junction obstruction.

Causes of renal pelvis obstruction

The exact causes of this anomaly is unknown, but genetic factors are thought to contribute. The structural abnormalities that block the passage of urine can include:

• Unusual twists or bends in the ureter
• A blood vessel compressing on the ureter
• Muscle anomalies in the ureteric wall.

Treatment for renal pelvis obstruction

Kidney dilatation is usually detected during pregnancy ultrasounds. A subsequent ultrasound of the baby is usually needed, once it is born, to confirm the diagnosis.

Treatment for renal agenesis

If both kidneys are missing, the baby will not survive. A baby can manage with one functioning kidney, since the organ enlarges to cope with the extra workload.

Where to get help

• Your GP (doctor)
• Paediatrician.