Sometimes kidney function can change quickly. For example, your kidneys may stop working properly because of a sudden loss of large amounts of blood (eg during surgery) or as a result of an accident, illness or infection. A sudden change in kidney function is called acute kidney injury. This is often temporary but can occasionally lead to lasting kidney damage.
More often kidney function worsens over a number of years – it is a chronic, or ongoing, condition. Chronic kidney disease is called a silent disease as there often no warning signs. Sometimes people lose up to 90% of their kidney functions before getting any symptoms.