Kidneys normally remove extra water and wastes from you blood. If they fail, blood levels of urea increase. Urea is toxic to the body and can affect all the major organs including the brain. Symptoms usually only appear when kidney function falls to less than 10 percent of normal. It precedes uremic coma and causes disorders of memory, thinking, speech, perception, emotions and other neurological manifestations.
Written by Dr K. Coetzee, reviewed by Dr R. Moosa, head of the Renal Unit, Tygerberg Academic Hospital.