There are many different kinds of kidney diseases. A disease of the kidney may be a short-term problem, and in this case might not cause permanent kidney damage. Examples include some kidney infections and kidney stones.
Dehydration, trauma, and some medications can also cause temporary changes in kidney function. Acute kidney injury (AKI) is a sudden or rapid decline of kidney function. Acute kidney injury may be reversed, or it may sometimes lead to permanent loss of kidney function.
More often, diseases that affect the kidney are chronic problems. Chronic kidney disease (CKD) is a loss of kidney function that occurs gradually. It is often "silent," going undetected for months or years.
In this case, once CKD is detected, kidney function may be monitored by periodic blood or urine tests from year to year. Close observation of your kidney function will allow your doctor to adjust the dose of medicines that are cleared out of your body through the kidneys. Monitoring of your kidneys will also allow your doctor to help predict whether you need special tests or treatments relating to your kidney disease.
Examples of chronic diseases that cause kidney damage over many years are high blood pressure, diabetes and polycystic kidney disease.
When the kidneys permanently lose 90 percent or more of their function, a person is diagnosed with “end-stage renal disease.” People with end-stage renal disease must undergo dialysis or receive a donated kidney by transplantation in order to stay alive.