When the kidneys faill, the blood must be purified via dialysis. This is because the accumulation of waste products in the blood can be life threatening. There are two methods for artificial blood purification: Hemodialysis and peritoneal dialysis.
In hemodialysis, the blood is continuously removed from the body and purified outside the body in an external machine using a dialysis fluid to help remove the toxins. The ‘purified’ blood is then returned and so the cycle continues. Each session lasts for about 4-5 hours and it usually takes place three times a week in a dialysis centre (or in some circumstances, it can be done at home.
Peritoneal dialysis can be performed independently at home. In this process, the blood is not filtered through a machine, but through the patient’s peritoneum; the membrane inside the stomach. About two litres of dialysis fluid are introduced into the patient’s abdominal cavity via an abdominal catheter, drained after several hours and replaced with new dialysis fluid.
However, dialysis cannot replace all renal functions, such as the production of the hormone erythropoietin, which is important for blood synthesis, or vitamin D, which is essential for bone synthesis. Many dialysis patients suffer from anaemia, bone metabolism disorders, high blood pressure, and reduced physical fitness.
If appropriate, kidney transplantation is the optimal form of kidney replacement therapy. However, if there is no living kidney donor then the waiting times for a deceased donor kidney may be long. Additionally, following kidney transplantation patients have to take medication to suppress the immune system for the rest of their lives. Without immunosuppression, their bodies would reject the donor kidney.
In end stage kidney disease, dialysis and kidney transplantation are the two major treatment options.