Kidney

PATHOLOGY TESTS SPEAK FOR YOUR HEALTH

PART I KIDNEY FUNCTION TESTS

BY DR SHREERAM VAIDYA

DATE : 31ST MARCH 2010TIME: 3.30 PMPLACE :HELP LIB

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Pathology is the bridge between normal physiology and abnormal physiology (Boyd)

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What do the kidneys do?

The kidneys are bean-shaped organs, each about the size of a fist. They are located near the middle of the back, just below the rib cage, one on each side of the spine. The wastes and extra water become urine, which flows to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination.

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NEPHRON

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Glomerular Filtration Rate (GFR): Your GFR tells how much kidney function

you have. It may be estimated from your blood level of creatinine. If your GFR falls below 30 you will need to see a kidney disease specialist (called a nephrologist), Your kidney doctor will speak to you about treatments for kidney failure like dialysis or kidney transplant. A GFR below 15 indicates that you need to start one of these treatments

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Microalbuminuria TestNormal albuminuria <30 mg 24hr albumin

excreation Microalbuminuria 30-300mg /dayIncrease renal and cardiovascular risk

Macroalbuminuria >300mg/day

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SERUM CREATININE Creatinine is a break down product of muscle

metabolism in the body.Measuring serum creatinine is a useful and

inexpensive method of evaluating renal dysfunction.

Creatinine is freely filtered and therefore the serum creatinine level depends on the Glomerular Filtration Rate (GFR). Renal dysfunction diminishes the ability to filter creatinine and the serum creatinine rises. If the serum creatinine level doubles, the GFR is considered to have been halved. A threefold increase is considered to reflect a 75% loss of kidney function.

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Adult males: 0.8 - 1.4 mg/dl: values are slightly higher in males due to larger muscle mass

Adult females: 0.6 - 1.1 mg/dl: creatinine clearance is increased in pregnancy, resulting in lower serum levels

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Reference values for serum creatinine:

Increased serum creatinine

Impaired renal function Chronic nephritis Urinary tract obstruction Muscle diseases Congestive heart failure Shock

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Decreased creatininelevels may be seen in: the elderly, persons

with small stature, decreased muscle mass, or inadequate dietary protein.

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Normal Creatinine Levels in Urine

The normal urine creatinine level may vary with age and gender. Men tend to have slightly elevated urine creatinine levels, as compared to women. This is because of the presence of more skeletal muscle mass in men. The rate of muscle metabolism slows down with age, and so, elderly people can have low urine creatinine levels. In case of a 24-hour urine sample test, the normal creatinine level can be anywhere between 500 to 2000 mg/day.

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What are the symptoms of kidney failure?

Kidney failure tends to happen gradually. Even if just one kidney works, or both work partially, normal kidney function is still possible. So, it can be a very long time before any symptoms are noticed by the patient. When symptoms do occur they tend to be different from person-to-person, making it harder for doctors to diagnose kidney failure quickly. The following symptoms may be present: Fatigue (tiredness)

Frequent need to urinate, especially at night. Frequency grows with time

Itchy skin Nausea Shortness of breath Water retention (swollen feet, hands, ankles) Blood in urine Protein in urine

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People with chronic kidney disease are usually affected by anemia (90% of them).

When levels of EPO (erythropoietin), which is produced by the kidneys, are low, anemia can develop. EPO makes the body produce red blood cells.

When your red blood cell count is low you have anemia.

Chronic kidney failure patients who have anemia are usually given an ESA (erythropoiesis-stimulating agent) injection.

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What are the causes of kidney disease?

Diabetes - thought to cause about half of all cases

Hypertension (high blood pressure) - thought to cause about one quarter of all cases

Inflammation of the kidney (glomerulonephritis)

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Why Kidneys Count?

The kidneys are the waste management system of the body, removing excess fluid and toxins from the blood stream and filtering them into the urine. The role they play is vital; if kidney function is significantly reduced and a patient develops end-stage renal disease (ESRD); the situation is life-threatening and a kidney transplant or regular dialysis treatments are the only treatment options.

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DIALYSISDialysis is the artificial replacement for lost

kidney functions.Dialysis is unable to produce erythropoietin ,calcitriol

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Why is dialysis necessary?

Approximately 1,500 liters of blood are filtered by a healthy person's kidneys each day. We could not live if waste products were not removed from our kidneys. People whose kidneys either do not work properly or not at all experience a buildup of waste in their blood. Without dialysis the amount of waste products in the blood would increase and eventually reach levels that would cause coma and death.

Dialysis is also used to rapidly remove toxins or drugs from the blood.

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Early Detection Saves KidneysTraditionally, kidney disease has been

considered an irreversible and progressive condition that will eventually lead to renal failure (called end-stage renal disease). But recent research shows that early detection can actually save kidney function.

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Early Detection Saves KidneysA 2003 study in the New England Journal

of Medicine found that if the earliest sign of kidney disease—microalbuminuria (or minute amounts of protein in the urine)—is detected it could be reversed if treated properly.

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