Kidneys are just not two 'kidney' shaped organs situated at the back of your tummy filtering urine and getting rid of waste products, but does much more, and safeguarding these organs are essential for wellbeing and survival.

Electrolyte balance
Common electrolytes in your body are Calcium, Chloride, Magnesium, Phosphorus, Potassium and sodium. These electrolytes carry an electric charge in your body. They affect the amount of water in your body controlled by the kidneys.

Kidneys have the ability to monitor the amount of body fluid the body should contain and filter waste-products of metabolism, like urea, creatinine and potassium among others. The kidneys also filter excess blood urea from protein metabolism and uric acid from DNA breakdown.

The acidity of your blood (pH), your muscle functions,is affected by your electrolytes and isproperly regulated by the kidneys. Kidneys and electrolytes control the blood pressure and stimulate the production of red blood cells.

Sensors in the kidneys
When blood runs through the kidneys, the sensors regulate the water balance and how much should be excreted along with the electrolytes mentioned above. It is a finely tuned mechanism and any disorder or malfunction in the kidneys shall lead to an electrolyte imbalance causing even water logging, coma and death. If a person drinks many glasses of water (some say 8 glasses) the kidneys will flush the excess out as dilute urine. Over-hydration due to drinking large volumes of water may cause brain oedema (swelling), lead to coma and death, as was presented one case on Current Affairs on Australian Television on 9th October 2014, supposed to have taken to detoxify the body.

On the contrary, if a person is dehydrated from exercise, or living in the tropics, or from excessive water loss as in diarrhoea, the kidneys will hold the water excretion and in such situations the scanty amounts of urine passed will be highly concentrated.

This system is controlled by a hormone called renin, which also can cause high blood pressure through narrowing (vaso-constriction) of blood vessels. This system is also referred to as "the renin-angiotensin-aldosterone system (RAAS) is a hormone system that regulates blood pressure and water (fluid)…

The blood through the kidneys passes through several times a day. Each kidney contains around a million units called nephrons, each of which is a microscopic filter for blood. It's possible to lose as much as 90% of kidney function without experiencing any symptoms or problems. An early symptom could be swelling (pitting oedema) around your ankles. See your doctor immediately. You could also get fatigue, skin rashes, a metallic taste in the mouth, nausea and vomiting, shortness of breath, dizzy spells, as early signs of kidney failure.

Erythropoietin
Kidneys also secrete a hormone called erythropoietin that stimulates the bone marrow to manufacture red blood cells. There are special cells in the kidneys that monitor the oxygen concentration in the blood. If the oxygen level drops kidney produces more erythropoietin to manufacture more red cells in the bone marrow.

How do the kidney functions fail?
This could happen within a short period (acute failure), or from chronic problems like diabetes (diabetic kidneys)

There are pre-renal causes that affect the kidneys indirectly, such as low blood volume due to loss through injury. In such a situation the kidneys can go into 'acute shock' as do in severe motor car accidents (crush injury)

Dehydration from vomiting, diarrhoea and high fevers can cause acute kidney failure. If you suffer from severe gastro-enteritis you should hydrate yourself by drinking plenty of water. Coconut water is a good substitute. Soda drinks with sugar are contraindicated as water tends to be drawn into such fluids (osmosis) and worsen the dehydration, especially among kids.

Some people habitually do not drink enough water- two litres a day. When taking certain drugs like metformin given for diabetes, should drink more water to prevent dysfunction of the kidneys. The radiologists will warn you to stop metformin 48 hours before giving dyes intravenously to take contrast X ray films. After such studies you need to flush your kidneys with plenty of water to prevent kidney damage from the iodine dyes.
One should not take diuretics without been prescribed by your family physician, which can cause excessive water and electrolyte loss, when taken daily.

Causes within the kidneys (damage directly)
Severe infection (Sepsis): The immune system in the body can breakdown in a severe infection, such as urinary tract infection (UTI).

Those travelling overseas requiring vaccines are cautioned that the kidneys could be affected if you suffer from a pre-existent kidney failure

Certain medications damage the functioning kidney tissue, such as non-steroidal anti-inflammatory drugs like ibuprofen, voltaren and naproxen. These drugs are prescribed for chronic arthritic conditions and long term use can inevitable damage your kidneys.

There are certain medications that damage your kidneys, such as aminoglycosides (Genta and Garramycin), lithium given for psychiatric situations, and iodine containing medications injected for radiological studies.

Rhabdomyolysis: A common drug that causes breakdown of muscles is statins. One fine day, your legs may give way due to significant breakdown of muscles in the body, especially the calf muscles. This could occur in traumatic crush fractures in accidents or burns. Fortunately, stopping statins gives relief overnight. In such situations better avoid statins and control your cholesterol blood levels through diet alone, or taking other medications. Your doctor will order a test (Creatine phosphokinase CPK test) to check such muscle breakdown. Such breakdown of muscles produces a protein called myoglobin, harmful to the kidneys and produce kidney failure.

Multiple myeloma is another bone disease that can cause kidney failure.

Post-renal causes: This happens when there is obstruction to the outflow of urine from the kidneys. Obstruction to the outflow occurs in obstructions in the bladder outlet, as in enlarged prostate gland or prostatic cancer.

Certain tumours within the abdominal cavity can cause pressure on the ureters that can cause kidney failure. Occasionally, the ureters are damaged following womb operations (hysterectomy) which are less frequent today.

Ureteric stones can cause obstruction in one ureter that can cause renal failure unless the stone is crushed or removed.

Chronic renal failure
This is a condition that is produced gradually for many years, and quite undetected unless blood tests are done to check on the kidney functions, including urinalysis.

This is a serious progressive condition among the uncontrolled diabetics. Diabetics should have yearly tests for blood creatinine, blood urea, and a test called eGR, plus urineanalysis for those excretory products.
Check urine for micro-albumin: Your urine needs to be checked for any leakage of albumin (protein) into the urine. Under normal conditions a trace may be present in the urine. Presence of micro albumin in the urine is an early sign of diabetic kidney disease.You should have your urine checked for micro albumin every year, if you suffer from diabetic kidneys.

Strict control of diabetes is essential to prevent chronic kidney failure leading to end-stage failure.

Poorly controlled high blood pressure is also another common situation where kidneys can chronically fail. Keep your BP less than 130/70 for males and 120/70 for females, at all ages.

General wellbeing
You cannot keep your kidneys in prime functional healthy state unless the total body overall health is kept in peak condition. A balanced diet, exercise, consuming a moderate volume of water, minding your salt intake, keeping your body weight within the normal range, leading a non-stressful life are all ingredients to maintain healthy kidneys.