Acute kidney injury (AKI), also known as acute renal failure, is a serious medical condition characterized by a sudden decrease in kidney function. It can be caused by a variety of factors, including dehydration, certain medications, and infections. Symptoms of AKI include decreased urine output, swelling in the legs and feet, fatigue, confusion, nausea and vomiting, and shortness of breath. If left untreated, AKI can lead to life-threatening complications such as kidney failure and even death.