Renal failure is a serious medical condition that occurs when the kidneys lose their ability to function properly. Synonyms for the term renal failure include kidney failure, renal insufficiency, and end-stage renal disease. The condition can be caused by various factors, including diabetes, high blood pressure, and certain medications. Some of the signs and symptoms of renal failure include fatigue, decreased urine output, nausea, and swelling in the legs and ankles. Treatment options for renal failure include dialysis and kidney transplant. It is important to seek medical attention immediately if you suspect you have any symptoms related to kidney function.