Chronic kidney disease, also known as chronic kidney failure, is a long-lasting and irreversible condition that is caused by damage to the kidneys.
Chronic kidney disease is a serious condition because our kidneys carry out several important functions within the body, such as filtering waste products from the blood and regulating blood flow.
The most common cause of chronic kidney disease is damage caused by other chronic (long-lasting) conditions, such as diabetes and high blood pressure.
Who is affected?
Estimates of the number of people with chronic kidney disease vary, but the condition is thought to affect between one and four people in every 1,000. The risk of developing chronic kidney disease increases with age. The average age of somebody with the condition is 77.
Chronic kidney disease is most common among South Asian, African and Afro-Caribbean communities.
Important functions that are performed by the kidneys are listed below.
Blood filtering
The kidneys contain millions of tiny filters known as nephrons. As blood passes through the kidneys, nephrons filter out excess fluid and waste products from the blood. These are then released from the body when we urinate.
However, if the nephrons become damaged, the kidneys can lose their filtering abilities, and dangerous levels of fluid and waste products can build up.
Damage to the kidneys may also result in anaemia (a condition where not enough oxygen is carried around the body due to a lack of red blood cells). This can cause muscle weakness, softening of the bones (osteomalacia) or rickets (a disorder that affects the development of the bones).
Regulatory function
The kidneys help regulate several important functions in the body, such as blood pressure and the levels of sodium and potassium in our bodies.
If this function is damaged, complications can include high blood pressure and hyperkalemia (a condition where the potassium levels in the body are too high). This can lead to the heart becoming damaged.
The kidneys also regulate the interactions between vitamin D and calcium. The vitamin D that we take from our diet is 'inactive' and needs to be slightly altered, or activated, by the kidneys before it can start to work. Vitamin D is essential for the absorption of calcium (needed to strengthen bones) and muscle function.
Hormonal function
The kidneys produce several important hormones (messenger chemicals that transmit information from one group of cells to another via the blood), including erythropoeitin. Erythropoeitin is involved in the production of red blood cells, which carry oxygen around our body.
Established renal failure
Sometimes kidney disease cannot be stopped and the kidneys lose almost all functioning capability. This is known as established renal failure (ERF) or end-stage kidney disease. People with ERF require either dialysis (a procedure where the blood is artificially filtered by a machine) or a kidney transplant in order to remain alive.
