Unlike acute renal failure with its sudden reversible failure of kidney function, chronic renal insufficiency is slowly progressive. It most often results from any disease that causes gradual loss of kidney function. It can range from mild dysfunction to severe kidney failure. Progression may continue to end-stage renal disease (ESRD). Chronic renal insufficiency usually occurs over a number of years as the internal structures of the kidney are slowly damaged. In the early stages, there may be no symptoms. In fact, progression may be so gradual that symptoms do not occur until kidney function is less than one-tenth of normal. Causes of chronic renal insufficiency include:
--Glomerulonephritis of any type (one of the most common causes)  
--Polycystic kidney disease  
--Alport syndrome  
--Reflux nephropathy  
--Obstructive uropathy  
--Kidney stones and infection  
--Analgesic nephropathy