Absent kidney

An absent kidney is a condition where a person has just one kidney. It can also be known as a solitary kidney, renal agenesis or renal dysplasia.

Why do some children only have one kidney?

There are several reason why a child may only have one kidney:

  • He or she may have been born with only one normal kidney. In many cases, this is discovered during a routine scan.
  • The child may have had one kidney removed due to disease or an accident.

How does the urinary system work?

The urinary system consists of the kidneys, the bladder and ureters. The kidneys filter the blood to remove waste products and form urine. Urine flows from the kidneys down through the ureters to the bladder. From here it passes through another tube (the urethra) to the outside, when urinating.

The ureters join the bladder at an angle, creating a flap (valve). This prevents urine flowing back from the bladder into the ureters and the kidneys (reflux). It also stops the high pressure created by urination from affecting the kidneys. This valve helps to get rid of the urine in the bladder in one go, as the urine cannot travel to anywhere else.

Why does a child with one kidney need regular check ups?

When a child is born with one normal kidney, he or she should have regular check ups with a specialist doctor, to make sure that the kidney is growing normally.

What are the risks of only having one kidney?

Life with one kidney should not be significantly different to life with two kidneys. Studies have found that people who have only one normal kidney are no more likely to develop kidney failure.

Will children with one kidney need to follow a special diet?

A child with one kidney will not have to restrict his or her diet unless the remaining kidney is not completely normal. In this case, the amount of salt and protein the child eats may need to be decreased. A doctor will tell the family if this is necessary. No other special diets are needed.

Can children with one kidney participate in sports?

Children need not restrict their activities. However, some doctors believe that children with one kidney should avoid sports, which involve a lot of body contact, like rugby or boxing.

Compiled by:
Compiled by the Renal Team in collaboration with the Patient Information Group.
Last review date:
May 2015