Thus, their function is both excretory and secretory. Kidney disease occurs when kidneys can no longer perform their functions at full capacity. Permanently decreased kidney function is referred to as chronic renal failure. Chronic renal failure can be the result of a gradual decrease in the efficiency of the kidneys over a long period or might be the consequence of a sudden kidney failure (i.e. acute renal failure). In the case of chronic kidney failure, the kidneys are irreversibly damaged. Many conditions can lead to chronic renal failure; the most prominent include diabetes, chronic kidney inflammation (glomerulonephritis) or hypertension and vascular damage.
When the kidneys fail, the production of urine is reduced and the urine components, i.e. water and waste products, accumulate in the body and thereby result in a syndrome referred to as uremia. Common symptoms of uremia are fatigue, anorexia, nausea and itching skin.