Healthy kidneys filter excess fluid, minerals and waste material from blood and convert it to urine. This, in turn, is stored in the bladder, from which is periodically evacuated. Kidneys also make hormones essential for strong bones and others necessary to adequate production of new red blood cells. While both kidneys need not be functioning perfectly--a person can survive with only one such organ--some minimum level of activity is essential to life. Given the current level of medical knowledge, chronic kidney failure is irreversible. It will eventually lead to total failure, commonly called end-stage renal disease (ESRD). Absent intervention to remove wastes and fluids (dialysis) or obtaining a suitable kidney for transplant, ESRD is always fatal. Thus, failing kidneys require some outside intervention for patients to continue life-sustaining functions. Treatment decisions cannot be made lightly. Just as the disease is life threatening, so the treatments are onerous. And they may involve life-style changes that some patients will find to much of a burden.
Like many other organ malfunctions, kidney failure contributes to other body function degradations, which, in turn, may aggravate the underlying kidney condition. One example is high blood pressure. Kidneys are stressed by--and may ultimately sustain permanent damage from--blood pushing through them at an excessive level of pressure over a long period of time. By the same token, kidneys that fail to remove excess fluid from the blood permit an increase in blood volume, which in turn may trigger an unwanted increase in blood pressure. Other possible causes of chronic kidney failure include cancer and duct obstructions such as kidney stones. (These and other contributing conditions may be treatable, however, and, as a consequence, their treatment may ameliorate the kidney condition as well.)