The kidneys are two organs that are located in the lower back, one on each side of the spine. They are about the size of a clenched fist. The Nephron is the functional unit of the kidney and contains a specialized structure called the glomerulus within which filtration of blood occurs.There are about a million nephrons in a kidney.The kidneys have numerous functions that are vital to your well being. Their main functions and a description of each are listed below.
FUNCTIONS OF THE KIDNEY
- Remove extra water:-The kidneys filter extra water, which the body does not need, in the form of urine. This water comes from the liquids you drink and the foods you eat. The kidneys have the ability to concentrate or dilute your urine, as your body needs. As they form urine, it is sent to the bladder through tubes called ureters. The urethra is the tube that drains the urine from the bladder to the outside of the body.
- Remove waste products:- Urea and creatinine are examples of waste products that are found in everyone. Urea and creatinine form as the body breaks down food into energy and performs its routine bodily functions. Waste products are harmful if not removed by the kidneys.
- Restore needed chemicals:- The kidneys work to keep the body’s chemicals (electrolytes and minerals) in balance. Two examples of electrolytes are sodium and potassium. An example of a mineral would be calcium. The kidneys keep a proper balance by saving the chemicals the body needs and passing the excess chemicals into the urine.
- Regulate blood pressure:-The kidneys help the body keep a normal blood pressure by passing extra sodium and water. The kidneys also produce a special hormone called renin that helps to control blood pressure.
Help in the production of red blood cells:- The healthy kidney produces a hormone called erythropoietin.This hormone helps the bone marrow produce red blood cells.
Help with calcium and vitamin balance:-The kidneys balance calcium, phosphate and Vitamin D. These three chemicals play a key role in bone formation.
KIDNEY FAILURE As kidney failure begins, the kidneys are not able to clean the blood of waste products. Waste products and excess water collect in the body. A build up of waste products in the blood is called uremia. Symptoms of kidney failure that a patient may have felt include:
- Extreme tiredness
- Nausea and vomiting
- Itchy skin
- Difficulty sleeping
- Puffiness & swelling of the feet, legs hands& face
- Shortness of breath
- Poor appetite
- Bad breath
- High blood pressure
It must be stressed that early on, in patients with kidney disease, there may be no symptoms at all. A common misconception exists with respect to the volume of urine passed. This unfortunately is not a good measure of kidney function; a patient with advanced kidney failure may still be able to pass more than a litre of urine.
Chronic renal failure means that the loss of kidney function is permanent. Kidney function may stop quickly, or slowly fail over a number of years. End Stage Renal Disease or ESRD occurs when the kidneys have reached the point where they can no longer work well enough to maintain the balances needed for life. This is usually when dialysis must be started.
COMMON CAUSES OF KIDNEY FAILURE
There are many causes of kidney failure and a few of the most common reasons are listed here:
Diabetes Mellitus This is the most common cause of chronic renal failure in India and all over the world. Diabetes causes blood vessel changes in the kidneys (and the whole body) over many years. A thickening and hardening of renal arteries, glomeruli and tubules cause the kidney’s to fail.
Glomerulonephritis In this disease, there is inflammation and destruction of the glomerulus. The glomerulus is the part of the kidney that filters the blood of waste products. When enough glomeruli are damaged, they cannot filter enough water and wastes and dialysis must be started.
Hypertension This is high blood pressure. The vessels become thick and narrow from constant high pressure to the blood vessels of the kidneys. Eventually, the kidneys fail because the flow of blood to the kidney is decreased.
Pyelonephritis This is an infection of the kidneys. Repeated infections of the kidneys may damage the nephrons causing kidney failure. The nephron is the part of the kidney that contains the glomerulus and the tubules. These are vital to the filtering of the blood.
Lupus Erythematosus Lupus is a chronic, inflammatory disease of the body’s connective tissue, especially capillaries and small blood vessels. Due to this chronic inflammation the blood vessels become scarred. This scarring leads to kidney failure.
Obstruction This usually occurs with kidney stones. It means that urine is not able to drain easily into the bladder and backs up into the kidneys. This will cause infections that will damage the kidneys.
Polycystic Kidney Disease In this condition, the kidneys are full of cysts. A cyst is a fluid filled sack. As these cysts slowly enlarge, they press against the working part of the kidney causing permanent damage. This is an inherited condition.
Structural Disorders This is from a defect in the urinary tract and is usually present at birth. If the urine is not able to drain well and backs up into the kidneys, infections will damage the kidneys.
Advice to patients at risk for kidney disease
All patients with Diabetes Mellitus and Hypertension (High Blood Pressure) are at risk for developing kidney disease. Patients with glomerulonephritis are also at risk to develop kidney failure. Such patients are advised to undergo regular follow-up with a nephrologist. Regular checks on urine-protein levels (Proteinuria) and kidney function (urea & creatinine levels) are mandatory. Therefore, a simple Blood test (serum creatinine) and Urine test (for protein) will determine whether your kidneys are functioning normally. The tests are cheap and together would cost about Rs 200.
Aggressive Blood Pressure control (aim for BP <120/80 mmHg) and the use of newer medicines (ACEI & ARB) holds the key to the management of such patients with a view to prevent progression of kidney disease.