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Once the symptoms of uremia develop, it becomes necessary to institute definitive
treatment in the form of dialysis or kidney transplantation.
Anemia in patients with renal failure
The kidneys manufacture a hormone called erythropoietin which is involved in the
production of Red Blood Cells. In chronic renal failure, the Erythropoeitin production
by the kidneys decreases and the patient becomes anemic.
The Renin-angiotensin System
Whenever there is a sustained fall in blood pressure, the decreased blood supply to the kidneys stimulates the release of
renin. Renin is converted to angiotensin.
Angiotensin has the following effects:
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It constricts the blood vessels, mainly the veins.
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It stimulates the release of aldosterone which helps retain sodium and water.
Thus the blood pressure is restored to normal
Proteinurea
Increased urinary excretion of protein is called as protein urea. Normal excretion of
urine protein is less than 150 milligrams/24 hours for adults. Anything in excess of
this is called as proteinurea.
Causes and detection of proteinurea
The following are some of the causes of protein urea:
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Diseases affecting the glomerulus e.g.
glomerulunephritis, nephrotic syndrome. |
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Injury to kidney tubules from drugs, antibiotics, metals or from very low blood
pressure. |
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Filtration of abnormal proteins across the glomerulus e.g.
Myeloma. |
This urine protein is detected by a test which is called dipstick and it depends on
the ability of proteins specially albumin to alter the color reaction of a pH sensitive
dye (tetrabromophenolpthalein) on a plastic strip. The proteinurea is quantified as
follows:
|
1+ |
Approx 30mg/dl |
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2+ |
30-100mg/dl |
|
3+ |
100-500mg/dl |
|
4+ |
> 2000mg/dl |
It is important that the person should see a physician to work out the cause of the protein urea. Usually, the amount of protein excreted in 24 hours is recorded. Some
patients may even need a biopsy of the kidney.
Pyuria
The excretion of white cells in the urine in excess of normal is called
pyuria. The
WBCs are determined by an examination of the urinary sediment after centrifugation
of the sample of approximately 10ccs of urine.
Abnormal WBCs in the urine exists when there are more than 5 White Blood Cells per high power field under the microscope. The most common cause is urinary
tract infection, but they can be seen in kidney stones, inflammation of the kidneys such
as interstitial nephritis.
Hematuria
Hematuria signifies the presence of blood in the urine.
Some of the causes of appearance of blood in the urine and method of
detection.
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Urologic causes
May be secondary to stones, tumors or infections. |
|
Patients with bleeding problems (coagulopathies). |
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Glomerular causes
e.g. glomerulonephritis. |
|
Diseases affecting the kidney tubules
Injury from antibiotics, drugs metals etc. |
Hematuria is detected by the use of the dipstick which includes a strip which
is impregnated with orthotoluidine. The blood reacts with the reagent which changes
the color of the test strip.
Hematuria is usually quantified by the number of Red Blood Cells per high power field under the microscope:
Normal values:
0 to 1 in males and may be slightly higher in females
The persistence presence in males or females of even small numbers of blood cells in the urine should be investigated. It is important to remember that menstruating women may have some RBCs in the urine. The urine examination should be repeated after the menstruation.
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