Proteinuria
Also known as: Protein in the
urine
What is it?
Normally, there is a small amount of protein
present in the urine. When the amount of protein
present in the urine rises to higher than normal
amounts, it is called proteinuria.
Who gets it?
Normal adults may urinate up to 150 mg of
protein per day and interestingly enough, in
adolescents this may be as high as 250 mg/day.
Higher amounts of protein may appear in our urine
after strenuous exercise or while we are ill with
a variety of common illnesses. This type of
proteinuria will quickly disappear and is of no
consequence. In one large study of healthy school
children between six and 12 years of age, about 3%
had mild proteinuria at some time or another and
about five children per thousand had abnormal
amounts of protein in a urine in each of three
separate occasions. Nephrotic syndrome, a group of
conditions in which urine protein is particularly
high, occurs in about 1-2 per 100,000 children
below the age of 16.
What causes it?
About 25% of all the blood the heart pumps
every day flows through the kidneys. There, the
blood is filtered through small vessels called
glomeruli. Normally, the" filtering slits" in
these glomeruli are big enough to let water and
waste products through, but small enough to keep
the red blood cells and almost all of the protein
in the bloodstream. Proteinuria can be caused by
changes in the size of these filtering slits or by
illness that damaged the kidney and its glomeruli.
Other causes of proteinuria include medications
that may damage the kidney, or being born within
abnormally shaped or functioning set of kidneys.
One common cause of proteinuria in adults is
long-standing diabetes mellitus.
What are the symptoms?
People who have moderate amounts of protein in
their urine may have no symptoms whatsoever. Those
with large amounts of protein in their urine may
develop swelling around their eyes, their abdomen,
or their feet. This is due to water retention and
will cause them to gain weight and perhaps feel
more tired than usual. The large amounts of
protein in their urine may cause abnormal amounts
of bubbles to be present in the toilet after they
urinate. Occasionally, these people may retain
enough fluid so that it goes to their lungs and
causes difficulty breathing.
How is it diagnosed?
Proteinuria is diagnosed by examining the
urine. The first test your doctor may do it is
simple urinalysis. Normal urine has very small
amounts of protein present. Larger amounts are
usually reported as 1+ to 4+. To confirm this
test, your doctor may send a sample of your urine
to laboratory to measure the actual amount of
protein present. Occasionally your doctor will ask
you to collect a timed sample, often 24-hours, to
learn how much protein you excrete each day.
What is the treatment?
The treatment of proteinuria depends upon the
amount of protein excreted and upon its cause.
There are many reasons for having proteinuria and
treatments vary, depending upon the specific
cause. Your doctor will need to perform other
tests, generally blood tests as well as X-ray or
ultrasound tests, to determine the cause of
proteinuria. Small amounts of protein the urine
may not need any therapy at all. Patients with
large amounts of protein in their urine will
probably need medication both to improve or
stabilize the kidney function as well as to help
them deal with their weight gain and swelling.
Self-care tips
High levels of proteinuria almost always
indicate a renal problem. Proteinuria may be the
first sign of renal disease and control of
proteinuria has been shown to help maintain kidney
function. Individuals who develop the symptoms of
proteinuria or who are told that they have
abnormal amounts of protein in their urine on
screening tests should have their kidney function
evaluated by their physician.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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