http://www.kidney.org/general/news/onekid.cfm
The kidneys perform many functions that are vital to good
health. It is not unusual, however, to have only one kidney to do the work that
two kidneys ordinarily do.
Why do people have a single kidney?
Many people are born with a single kidney. This occurs in about one out of 750 people. Being born with a single kidney is more common in males, and the left kidney is the one more often absent. The ureter (the tube that takes urine from the kidney to the bladder) on the affected side is usually abnormal or absent. An abnormality of the reproductive tract may also be seen on the same side. This occurs more often in females than in males.
In other cases, one kidney may need to be surgically
removed, leaving a single remaining kidney. A kidney may need to be removed
because of an anatomic abnormality such as obstruction, or because of a tumor,
or from a sever traumatic injury after an accident.
How is a single kidney different?
The single normal kidney will grow faster and get larger
than a normally paired kidney. For this reason, the single kidney is larger and
heavier than normal, and it is, therefore, more vulnerable to injury. It is
important to be aware of the increased risk for injury with certain heavy
contact sports, so that careful decisions may be made regarding participation in
various physical activities. The American Academy of Pediatrics, American
Academy of Family Physicians and the Medical Society of Sports Medicine have
suggested that people with one kidney avoid sports that involve higher risks of
heavy contact or collision. This includes boxing, field hockey, football, ice
hockey, Lacrosse, martial arts, rodeo, soccer and wrestling. Anyone with a
single kidney who decides to participate in these sports should be extra careful
and wear protective padding. He or she should understand that the consequences
of losing a single kidney are very serious.
Are there long-term problems for people with a single kidney?
In general, most people with a single normal kidney have
few or no problems, particularly in the first few years. However, some longer
term problems have been recognized. Most doctors believe that people with a
single kidney, particularly from birth or during early childhood should be
followed more closely than people with two normal kidneys. Children who have had
a kidney surgically removed may have a slightly increased chance of developing
abnormal amounts of protein in the urine and some abnormality in kidney function
by 25 years later. Similar abnormalities have been found in individuals born
with a single kidney. In addition, there is greater chance of developing high
blood pressure. The decrease in kidney function is usually mild, and life span
is normal.
Are dietary changes needed?
In general, special diets are not needed by individuals who have one healthy kidney.
Speak to your doctor or a registered dietitian if you have
questions about the basic ingredients of a healthy diet.
How often should someone with one kidney see a doctor?
A urinalysis (urine test) and blood pressure check should
be done yearly, and kidney function should be checked every few years, or more
often if an abnormal urinalysis or blood pressure is found.
What special precautions are recommended for transplant patients?
Because the transplanted kidney is usually placed into the pelvis, these kidneys are in a location providing less protection and, therefore, are more easily injured. Consequently, the same recommendations of avoiding heavy contact and collision sports apply to the people who have had a kidney transplant.
Careful testing has shown that the transplanted kidney can
increase its function as in other situations resulting in a single kidney,
reaching a level of function that is about 40 percent greater than a normal
level.
What if I have more questions?
If you have more questions, you should speak to your doctor. You may also be interested in other National Kidney Foundation publications including:
Your Kidneys: Master Chemists of the Body
Detecting Kidney and Urinary Tract Abnormalities Before Birth
Answering Your Questions About Living Donation