In unilateral renal dysplasia, part or all of one kidney does not fully develop while a baby is growing in the womb. (‘Unilateral’ means one side.) It may be smaller than a normal kidney and may have cysts, which are like sacs filled with liquid.
The other kidney usually looks and works normally. Most people have no long-term problems with unilateral renal dysplasia, and some do not know that they have one kidney that is smaller than usual.
Before birth
Unilateral renal dysplasia may be suspected on the 20 week antenatal ultrasound scan, which looks at your baby growing in the womb. It may be suspected if one or both of the kidneys look smaller than usual or otherwise look abnormal
The scan also measures the amount of amniotic fluid (or liquor), the fluid that your baby floats in. The baby’s kidneys start making urine and pass this out into the amniotic fluid. This fluid protects your baby from getting hurt from the outside and helps his or her lungs mature so he or she is ready to breathe after birth.
If there is not enough amniotic fluid (oligohydramnios), this may be a sign that the kidneys are not working well, and that there may be problems breathing after birth.
You may need more ultrasound scans during the pregnancy to find out how the dysplasia is affecting your baby. It does not usually have an impact on how your baby is delivered.
Tests after birth
After your baby is born, he or she may need some imaging tests (scans) to confirm the condition and look for any complications. These use special equipment to get images of the inside of the body.
- Ultrasound scan – looks at look at the shape and size of your baby’s kidneys and other parts of the urinary system. A small handheld device is moved around your child’s skin and uses sound waves to create an image on a screen.
- DMSA scan – checks for any damage on the kidneys. A chemical that gives out a small amount of radiation is injected into one of your child’s blood vessels. This chemical is taken up by healthy parts of the kidney and a special camera takes pictures.
- MAG3 scan – for babies who also have antenatal hydronephrosis, this shows how much blood is going into and out of their kidneys, and whether they are passing urine normally. As in the DMSA test, a chemical that gives out a small amount of radiation is injected into a blood vessel, and a special camera takes pictures.
- Cystourethrogram or MCUG (sometimes called a VCUG) – usually for babies and children who are suspected of having antenatal hydronephrosis caused by vesicoureteral reflux (VUR). In this condition, some urine refluxes (goes back up) the wrong way up the ureters, towards, and sometimes into, the kidney. This test can check how your baby is passing urine. A special X-ray machine takes a series of images of the bladder while your baby is passing urine.
Unilateral renal dysplasia: complications and treatment
In most cases, babies do not need treatment. A small number of children have symptoms or complications, which may not happen until later in life. These may need follow up or treatment, such as medicines.
High blood pressure
Some children develop hypertension, blood pressure that is too high.
If your child has hypertension, he or she will need to reduce his or blood pressure so it is in the healthy range. Your child will probably need to eat a no-added salt diet, and may need to take medicines, to control his or her blood pressure. It is also recommended that all children, especially those with hypertension, keep to a healthy body weight and exercise regularly.
Occasionally, children who have a dysplastic kidney that is not working well and have blood pressure that cannot be controlled, will need the kidney removed in an operation called a nephrectomy. You may be referred to a paediatric nephrologist, a surgeon who treats children with problems in their urinary system, to discuss the operation.
Urinary tract infections
Some children get urinary tract infections (UTIs), when germs get into the urine and travel up the urinary tract (or system) and cause an infection, usually in the bladder. Babies and children with UTIs may become irritable, have a fever, have pain when they wee, feel sick or be sick.
UTIs that keep coming back are more likely in children who also have vesicoureteral reflux (VUR), when some urine refluxes (goes back up) towards, and sometimes into, the kidneys.
If your child has a UTI, he or she will need to take antibiotics, medicines that kill the germs.
If you think your child has a UTI, seek medical advice.
Chronic kidney disease
In most people with unilateral renal dysplasia, the other kidney works normally. The normal kidney can work harder to compensate and do the work of two kidneys.
Sometimes children with unilateral renal dysplasia have an abnormality in the other kidney. If the other kidney does not work normally, your child may have reduced kidney function. He or she may be at greater risk of progressing to later stages of chronic kidney disease (CKD), and will need more monitoring.
About the future
Many children will have no long-term problems. The other kidney usually grows larger to do the work of two kidneys.
Your child should be able to do all the things that other children their age do. He or she can go to nursery and school, play with other children and stay active.
Follow up
In the first few years of his or her life, your child may need to go back to the hospital for some tests. Later, he or she need to see your family doctor about once a year. It is important to go to these appointments even if your child seems well. You will also have the opportunity to ask any questions. At these appointments your child may have:
- his or her blood pressure measured, to check for hypertension
- urine tests – to check for protein in his or her urine (proteinuria), which may be a sign of problems in the kidney. You or a nurse collect some of your child’s urine in a small, clean container. A dipstick will be dipped into the urine – this is a strip with chemical pads that change colour if there is protein in the urine.
Living healthily
Your child can help protect his or her kidneys, and reduce the risk of hypertension later in life, by leading a healthy lifestyle through their child and adult years. This includes:
- eating a healthy diet – with at least five servings of fruit and vegetables a day, taking care not to eat too much salt, sugar and fats (especially saturated fats)
- getting plenty of exercise
- not smoking.
Further support
This can be a difficult and stressful experience for you and your family.
If you have any concerns or need additional support, speak with your doctor or nurse.