Dr. MJ Bazos MD,
What's the role of proteins in the
Proteins are essential in our bodies. Normally,
proteins move around in our blood, carrying food, hormones and medicine to all
parts of the body. They also help keep water inside tiny blood vessels.
What is proteinuria?
Proteinuria is the name of a medical condition.
It means protein is in the urine. As blood moves through the kidneys, the
kidneys filter out waste products, excess fluid and salts. The clean blood
cycles back through the body. Most proteins are too big to go through the
kidneys, so usually no protein is found in urine. If your doctor finds protein
in your child's urine, that means your child's kidney may not be working as they
should--possibly because of inflammation (swelling). Sometimes infection or
toxic chemicals damage the kidneys, and this makes protein show up in the urine.
Dipping a special strip of paper into a sample
of urine tells your doctor if protein is in it. If only a little protein is in
the urine, your child probably has a benign (harmless) condition such as
orthostatic proteinuria (see below). Your doctor might do a few other tests to
Your doctor may ask you to collect a 24-hour
urine sample from your child. Directions for doing this are at the end of this
handout. A 24-hour urine collection lets your doctor measure the protein in the
urine. This test helps show how well your child's kidneys are working. Your
doctor may also do some blood tests.
If a lot of protein is found in your child's
urine, a more serious kidney disease might be the problem. Proteinuria doesn't
cause pain. But when a lot of protein is in the urine, the level of protein in
the blood may go down. This can cause swelling in your child's eyelids, ankles
and legs. High blood pressure is another sign of this problem.
What is orthostatic proteinuria?
Orthostatic proteinuria occurs in some older
children and teenagers. The word orthostatic means "upright." The condition is
called "orthostatic proteinuria" because protein goes into the urine only when
the child is in the upright position (standing up).
Children with this condition have no kidney
damage but, for some unknown reason, they lose protein into the urine during the
day when they are active. At night, while they sleep, their kidneys don't let
any protein into the urine. Your doctor diagnoses this harmless condition by
checking 2 urine samples. The first is collected in the morning, right after
your child gets up. The second sample is collected throughout the day. The 2
samples are kept in separate containers. If your child has orthostatic
proteinuria, the morning sample won't have protein in it, but the urine
collected during the day will have protein in it.
How is proteinuria treated?
If your child has orthostatic proteinuria or
only small amounts of protein in the urine, no treatment is needed. Sometimes
your doctor will check your child's urine again after a few months. Your doctor
wants to see if the amount of protein in the urine goes down. If the amount of
protein in the urine doesn't change or if there is more protein, your doctor may
send your child to a kidney specialist (called a nephrologist--say:
neff-rollo-gist). The nephrologist may perform a kidney biopsy. (A small piece
of kidney tissue is taken out using a needle, and looked at under a microscope.)
When your doctor finds out what causes the protein in your child's urine, he or
she can find the best way to treat the problem.
No matter what caused the kidney problem, a few
simple things can help your child. Eating less salt can reduce the swelling.
Medicine can control the inflammation (swelling) of the kidneys that may be
causing protein to get into the urine. The medicine is usually given in a high
dose at first, and in a lower dose later on. Some children take a low dose of
medicine for months, or even years. It's important to follow your doctor's
instructions about taking the medicine. It's also important to visit the doctor
for regular checkups.
Do I need to restrict my child's
No. Although protein in the urine can increase
during exercise, this won't hurt your child's kidneys. So you don't need to
restrict your child's activities.
How do I do a 24-hour urine
In children who are potty-trained, you should
start the collection on a day when your child doesn't go to school, usually on a
Sunday. As soon as your child gets out of bed in the morning, have him or her
urinate into the toilet. This urine is not saved; just flush it down the toilet.
Write down the exact time your child urinates. (Children who aren't
potty-trained usually go in the hospital for this test.)
After this, whenever your child needs to
urinate, have your child urinate in the special container the doctor or the
laboratory gives you. For girls, collect the urine first in a urine "hat," then
pour it into the special container. You don't need to mark the times when these
urine samples are collected. Be sure to wash your hands after handling the
It's important to collect all the urine your
child produces all day and in the night. The next morning, wake your child up at
about the same time as you did the day before. Have your child urinate into the
container one last time. This ends the 24-hour collection. Now write the date
and the time on the container label. Bring the container to the lab on this day.
Since bacteria can grow in urine at room temperature, it's important to keep the
urine container in a refrigerator during the collection and before you deliver
it to the lab.