Like the eyes and the lungs, most of us have two kidneys. However, as many as 1 in 1,000 infants are born with only one functioning kidney. In the past, most individuals did not know they had one kidney, and did not have any health issues. Today most women have an ultrasound
during their pregnancy and most infants with a single kidney are discovered before they are born. An even larger group of infants have only one functioning kidney due either to severe malformation or obstruction of the other kidney.
Why Does This Happen?
For most infants with a single kidney, we do not know why this happens. Occasionally, it is part of a larger problem with other organs affected, called a syndrome. For the vast majority of infants, no identifiable cause can be found, although it occasionally can be associated with maternal diabetes and certain medications taken during pregnancy. This is one of the reasons for getting early prenatal care.
Is it Genetic?
For the majority of families of a child with a single kidney, the risk of a second child with a similar problem is very low, but this should be discussed with your pediatrician
or obstetrician who may refer you to a genetics
What are the Long Term Problems for a Person with a Single Kidney?
Most people with a single kidney lead full and normal lives, provided that kidney is normal. This is why a person with two kidneys can donate one kidney to a person with kidney failure. A healthy single kidney typically grows faster than a normal kidney and will be bigger than a normal kidney. This extra growth is good and helps the single kidney to do the work of two kidneys. However, the single kidney is not always formed properly.
Your child’s pediatrician will perform tests to detect any problems with that kidney. These may include:
- Blood tests to check the function of that kidney.
- Imaging studies such an ultrasound to make sure the kidney tissue looks normal and there is no stretching where the urine collects in the kidney.
- Voiding cystourethrogram (VCUG) to make sure the urine doesn’t go back up into the kidney when the infant voids or that there is any blockage to the flow out of the bladder.
- Nuclear medicine study to check the function of the kidney and make sure the urine is getting out of the kidney and into the bladder normally.
Blood Pressure & Urine Checks
A few individuals with a single kidney may develop kidney problems later in life such as high blood pressure
or protein in the urine
. The American Academy of Pediatrics (AAP) recommends infants and children with a single kidney should have their blood pressure checked each year and their urine tested for protein as part of their routine well-child care
. Adults with a single kidney should also have periodic checks of their blood pressure and urine.
What About Playing Sports?
Fortunately, the kidneys are located deep in the body and are less likely to be injured compared to the head, spleen, or liver.
The AAP recommends that children and adolescents with a single kidney be allowed to play most sports. This decision, however, should be based on several factors, such as the:
- Advice of your pediatrician
- Current heath of your child
- Sport in which he is participating
- Position he would play
- Level of competition
- Maturity of your child
- Relative size of the other participants in contact/collision sports
- Availability of protective equipment
- Whether the sport can be modified to allow safer participation
- Ability of your child’s coach to understand and accept the risks involved in participation
Padding designed specifically to protect the kidney should also be considered when making this decision, although little is known on its effectiveness.
What Should Parents of a Child with a Single Kidney Do?
Children with a single kidney should be treated no differently than other children. They do not need special diets. They, like children with two kidneys, need regular well-child care
as recommended by the AAP.