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What do our kidneys do?
Kidneys are essential to our lives. Each kidney acts as a filter.
- It eliminates waste (urea and creatinine) delivered by blood and drains them away into urine.
- It maintains a constant volume of water and mineral salts inside the body (sodium and potassium) by adjusting their elimination through urine.
It also produces hormones and vitamins which are essential to ensure important functions such as:
- the production of red blood cells by the bone marrow through erythropoietin (EPO)
- the regulation of blood pressure thanks to a proper balance in hormone production (renin and angiotensin)
- the preservation of bones through the active form of vitamin D
Kidney insufficiency results from the progression of diseases that destroy kidneys. Little by little, the body gets poisoned by the waste that the kidney does not eliminate anymore.
Kidney insufficiency is considered as chronic when the loss of this function is gradual and the damage to the kidneys irreversible. In many cases, the process is gradual and takes several years.
Renal function is measured by the level of blood creatinine but this level varies according to the muscle mass and gender of the individual. That is why the level of kidney insufficiency is defined by the glomerular filtration rate, itself measured more precisely by creatinine clearance.
According to the French classification, kidney insufficiency comprises four stages:
- Stage 1: chronic renal disease without kidney insufficiency: clearance ≥ 60ml/min/1.73 sqm
- Stage 2: Moderate kidney insufficiency : clearance between 30 and 59 ml/min/1.73 sqm
- Stage 3: Severe kidney insufficiency: clearance between 15 and 29 ml/min/1.73 sqm
- Stage 4: Terminal kidney insufficiency: clearance < 15 ml/min/1.73 sqm
Terminal kidney insufficiency is the ultimate stage of chronic kidney insufficiency: the loss of renal function is such that the person is in danger in the short term. Indeed the kidney is no longer able to get rid of toxins and potassium. Hyperkalemia (too much potassium in the blood) may result in a heart attack. The daily urinary elimination (diuresis) is not appropriate and leads to an excess of body water and salt. This overload of water and sodium may also cause arterial hypertension. Furthermore, a deficit in the production of erythropoietin by the ill kidney will result in anemia.
At the ultimate stage of chronic kidney insufficiency, a substitute treatment is necessary.
Additional treatments allow the replacement of kidney functions. These are called substitute treatments. There are two types of such treatments: dialysis and kidney transplant
- Dialysis: hemodialysis or peritoneal dialysis
- Kidney transplant
Some patients receive a kidney transplant right away without having recourse to dialysis while others receive a transplant after several years of dialysis. In cases of transplant rejection, and pending a new transplant, the patient is returned to dialysis. Finally, some patients are on dialysis all life long.
Thanks to these treatments, kidney insufficiency is no longer a killing disease.
An individual suffering from chronic kidney insufficiency should be able to choose freely among the various treatment modalities by means of clear and complete information from the nephrologist and his staff. It is always possible to be assisted by a trustworthy person of one’s choice.
What is the purpose of dialysis?
Dialysis is a substitute treatment which only partially replaces the renal function. It clears the blood from the waste and water (or toxins) excessively accumulated in the body.
- the purification of blood from non- eliminated waste by sick kidneys (urea, creatinine…),
- the rebalancing of water and other dissolved substances within the body.
It also helps recovering one’s appetite and physical shape so as to improve the quality of life and facilitate social and professional reintegration.
Undergoing dialysis therapy means a number of constraints, among which attending regular sessions and following a special diet with limited intake of water, salt, potassium and phosphorus.
There are two main dialysis techniques:
- Hemodialysis: the blood is being filtered through an artificial membrane. This technique requires an easy access to the blood, the so-called vascular access. The intervention can either be performed at the patient’s home or in a dialysis center. As for the management of medical costs reimbursements, it can either be public, private, or left to a community.
- Peritoneal dialysis, which usually takes place at the patient’s home.
Under certain conditions, it is possible to switch from one technique to the other.
When should the dialysis begin?
- As soon as the everyday life becomes too difficult, due to symptoms such as tiredness, loss of appetite, headaches resulting from arterial hypertension, ankle edema, and breathlessness due to an excess of water and salt, and finally anemia.
- Dialysis is also necessary when the glomerular filtration rate is inferior to
- 15 ml/min/1.73 sqm, i.e. when urea and creatinine levels are too high.