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Why is There Protein In
Your Urine When You Do A Full Body Checkup?
Proteinuria is an abnormally high amount of
protein in the urine. Proteins in the blood,
like albumin and immunoglobulin, help coagulation
(clotting), balance bodily fluids, and fight
infection. The kidneys remove wastes from protein-rich
blood through millions of tiny filtering screens
called glomeruli.
Most proteins are too large to pass through the
glomeruli into the urine. The glomeruli are negatively
charged, so they repel the negatively charged
proteins. Thus, a size and charge barrier keeps
protein molecules from entering the urine. But when
the glomeruli are damaged, proteins of various sizes
pass through them and are excreted in the urine.
Types
The following five types of proteinuria are
distinguished by milligrams (mg) of protein measured
during a 24-hour urine collection:
1. Microalbuminuria 30 - 150 mg
2. Mild150 ? 500 mg
3. Moderate500 ? 1000 mg
4. Heavy1000 ? 3000 mg
5. Nephrotic rangemore than 3500 mg
As kidney disease progresses, more protein enters the
urine. People with nephrotic-range proteinuria
typically have extensive glomeruli damage and usually
develop nephrotic syndrome.
Causes and Risk Factors
Hypertension and diabetes are the two biggest risk
factors for proteinuria. Old age and weight gain also
increase the risk. The following conditions cause
proteinuria:
Acute glomerulonephritis
Amyloidosis (protein deposits associated with chronic
disease)
Focal glomerulonephritis
Hypertension
IgA nephropathy
Mesangial proliferation
Minimal change disease Signs and Symptoms
Foamy urine and swelling (edema) are two signs of
proteinuria that become more evident as the disease
progresses. Excess protein can cause the urine to foam
in water. This occurs because protein changes the
surface tension between urine and water. Edema usually
only occurs in nephrotic range proteinuria.
Albumin is particularly useful in absorbing bodily
fluid into the blood. Because the albumin molecule is
relatively small, it is often among the first proteins
to enter the urine after glomeruli are damaged.
Therefore, even minor kidney dysfunction is detectable
with proper diagnosis of micoralbuminuria. Reduced
albumin level in the blood causes fluid retention and
swelling that is first noticeable in the hands, lower
legs, and feet. In more serious cases, the abdomen and
face may swell.
Orthostatic proteinuria is a disorder seen
occasionally in children and young adults who leak
significant amounts of urine when they are upright (orthostatic).
Presumably, standing increases the pressure on the
glomeruli and causes more protein to enter the urine,
while lying down relieves pressure and causes less
protein leakage. This is a benign disorder that most
young people outgrow.
Complications
Hypertensive people who develop proteinuria stand a
significant chance for kidney failure. African
Americans are 20 times more likely than Caucasians to
develop hypertensive-related kidney failure.
Proteinuria in people with diabetes may be a sign that
kidney disease is worsening. Microalbuminuria is often
cited as a risk for coronary artery disease (CAD) and
is often diagnostic of it and related cardiovascular
conditions.
By nephrologychannel.com
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