1. The Kidney
  2. The Function
  3. The Causes
  4. The Disease
  5. The Detection
  6. The Treatment
  7. The Prevention

     In humans, the kidneys are located in the abdominal cavity, in a space called the retroperitoneum. There are two, one on each side of the spine. They are approximately at the vertebral level T12 to L3. The right kidney sits just below the diaphragm and posterior to the liver, the left below the diaphragm and posterior to the spleen. Resting on top of each kidney is an adrenal gland.

     The asymmetry within the abdominal cavity caused by the liver typically results in the right kidney being slightly lower than the left, and left kidney being located slightly more medial then the right. The upper (cranial) parts of the kidneys are partially protected by the eleventh and twelfth ribs, and each whole kidney and adrenal gland are surrounded by two layers of fat (the perirenal and pararenal fat) and the renal fascia.

     Each adult kidney weighs between 125 and 170 grams in males and between 115 and 155 grams in females. The left kidney is typically slightly larger than the right.

     The kidney has a been-shaped structure, each kidney has concave and convex surfaces. The concave surface, the renal hilum, is the point at which the renal artery enters the organ, and the renal vein and ureter leave. The kidney is surrounded by tough fibrous tissue, the renal capsule, which is itself surrounded by perinephric fat, renal fascia ( of Gerota) and paranephric fat. The anterior (front) border of these tissues is the peritoneum, while the posterior (rear) border is the transversalis fascia.

     The superior border of the right kidney is adjacent to the liver; and the spleen, for the left border. therefore, both move down on inhalation. The kidney is approximately 11-14 cm in length, 6 cm wide and 3 cm thick.

The kidneys have four (04) main roles in the body:

(a) Excretion of wastes

The kidneys excrete a variety of waste products produced by metabolism. These include the nitrogenous wastes urea, from protein catabolism, and uric acid, from nucleic acid metabolism.

 
(b) Acid-base homeostasis
 
Two organ systems, the kidneys and lungs maintain acid-base homeostasis, which is the maintenance of pH around a relatively stable value. The kidneys contribute to acid-base homeostasis by regulating bicarbonate (HCO3-) concentration.
 
 
(c)  Blood pressure regulation
 
Long-term regulation of blood pressure predominantly depends upon the kidney. This primarily occurs through maintenance of the extracellular fluid compartment, the size of which depends on the plasma sodium concentration. Although the kidney cannot directly sense blood pressure, changes in the delivery of sodium and chloride to the distal part of the nephron alter the kidney's secretion of the enzyme renin.
 
(d)  Hormone secretion
 
The kidneys secrete a variety of hormones, including erythropoietin, calcitriol, and renin. Erythropoietin is released in response to hypoxia (low levels of oxygen at tissue level) in the renal circulation. It stimulates erythropoiesis (production of red blood cells) in the bone marrow. Calcitriol, the activated form of vitamin D, promotes intestinal absorption of calcium and the renal reabsorption of phosphate. Part of the renin- angiotensin-aldosterone system, renin is an enzyme involved in the regulation of aldosterone levels.

 

Kidney failure can occur from an acute situation or from chronic problems.

In acute renal failure, kidney function is lost rapidly and can occur from a variety of insults to the body. The list of causes is often categorized based on where the injury has occurred.
 
Prerenal (pre=before + renal=kidney) causes are due to decreased blood supply to the kidney.
 
Examples of prerenal causes of kidney failure are: 
  • Hypovolemia (low blood volume) due to blood loss
  • Dehydration from loss of body fluid (For Example: vomiting, diarrhea, sweating, fever)
  • Poor intake of fluids
  • Medication, For Example : diuretics ("water pills") may cause excessive water loss 
  • Abnormal blood flow to and from the kidney due to obstruction of the renal artery or vein
 
Renal causes of kidney failure (damage directly to the kidney itself) include:
  • Sepsis: The body's immune system is overwhelmed from infection and causes inflammation and shutdown of the kidneys. This usually does not occur with urinary tract infections.
  • Medications : Some medications are toxic to the kidney, including non-steroidal anti-inflammatory drugs like ibuprofen and naproxen. Others potentially toxic medications include antibiotics like aminoglycosides.
  • Rhabdomyolsis: This is a situation in which there is significant muscle breakdown in the body, and the damaged muscle fibers clog the filtering system of the kidneys. This can occur because of trauma, crush injuries, and burns. Some medications used to treat high cholesterol can cause rhabdomyolysis.
 

Symptoms of kidney disease can vary from person to person. Some people with kidney disease may not even feel sick, or they may not notice their symptoms.

If the kidney function fails, the waste products accumulate in the blood and the body, termed azotemia. Very mild levels of azotaemia may produce little or no symptoms. but if the kidney failure continues then symptoms will become noticeable (if the failure is of sufficient degree to cause symptoms). Renal failure accompanied with noticeable symptoms is termed uraemia.

Symptoms of kidney failure include:

** High levels of urea in the blood, which can result in :

       -   Vomiting and/or diarrhea, which may lead to dehydration 

       -  Nausea

       -  Weight loss

       -  Nocturnal urination

       -  Foamy or bubbly urine

       -  More frequent urination, or in greater amounts than usual, with pale urine

       -  Less frequent urination, or in smaller amounts than usual, with dark coloured urine

       -  Blood in the urine

       -  Pressure, or difficulty urinating

Many of the causes of kidney failure strike at random, and cannot be predicted or prevented. Others, such as diabetes, are present for many years before they develpo into kidney failure. When this is so, there is an opportunity for early diagnosis and prevention of progression of kidney failure to end stage. Recent advances in  our understanding of the nature of kidney failure have identified some classes of drugs that seem to particularly protect the kidneys, and to slow or in some cases prevent the gradual deterioration of the kidneys.

This new research has created a great deal of interest in the possibility of picking up kidney failure early and offering preventative treatment before the kidneys are completely destroyed. These early detection and prevention programme are particularly targeted at high-risk groups such as those who have diabetes, high blood pressure, a family history of kidney disease or other predisposing factors. 

If you or a member of your family fall into these groups, you should talk to your local doctor about being tested for kidney failure. These are several tests that can detect kidney disease. The initial basic testing procedures can be performed by your GP. If a problem with the kidneys is detected, further testing is necessary. 

The tests that can confirm the presence of kidney disease include:

Blood Tests :  These measure blood levels of creatinine and urea. Both of these products are normally excreted in the urine, but if the kidneys are not functioning properly, increased amounts can be detected in the blood.

Urine Test :  The presence of protein in the urine, simply diagnosed with a dipstick test, can often be marker for silent kidney disease.

Renal Imaging :  Involves taking a picture of the kidney using a variety of methods, such as ultrasound, CAT scan or magnetic resonance imaging. These tests help determine if there are any unusual growths or blockages to the flow of urine.

Renal biopsy :  A hospital procedure in which a needle is inserted through the skin into the kidney. A small sample of kidney tissue is removed for microscopic examination.   

Your kidneys filter wastes from your bood and regulate other functions of your body. When your kidneys fail, you need treatment to replace the work your kidneys normally perform.

Developing kidney failure means you have some ddecisions to make about your treatment. You may choose to forgo treatment. If you choose to receive treatment, your choices include:

  • Hemodialysis  - which requires a machine used to filter your blood outside your body.
  • Peritoneal Dialysis - which uses the lining of your belly to filter your blood inside the body.
  • Kidney Transplantation  - in which a new kidney is placed in your body.

Each treatment has advantages and disadvantages. Your choice of treatment will have a big impact on your day-to-day lifestyle, such as being able to keep a job if you are working. You are the only one who can decide what means most to you.

Reading this information is a good way to learn about your options so you can make an informed choice. And, if you find that your choice is not a good fit for your life, you can change treatments. With the help of your health care team, family, and friends, you can lead a full, active life.

Lifestyle changes can keep your kidneys healthy

Making healthy lifestyle choices can help to keep your kidneys functioning well:

** Eat lots of fruit and vegetables including legumes (peas or beans) and grain-based food like bread, pasta,
    noodles and rice.

** Eat some lean meat like chicken and fish each week.

** Eat only small amounts of salty or fatty food.

** Drink plenty of water instead of other drinks.

** Maintain a healthy weight.

** Stay fit. Do at least 30 minutes of physical activity that increases your heart rate on five or more days of the
    week including walking, lawn mowing, bike riding, swimming or gentle aerobics.

** Don't smoke.

** Limit your alcohol to two small drinks per day if you are male or one small drink per day if you are female.

** Have your blood pressure checked regularly.

** Do things that help you relax and reduce your stress levels.