A kidney contusion, or bruised kidney, usually heals on its own within a week, according to the Sportsinjuryclinic.net. A patient with a bruised kidney requires close monitoring for a few days.
Bruised kidneys generally occur as a result of a direct impact in the lower back, notes the Sportsinjuryclinic.net. Many times, the injury occurs during a motor vehicle accident, physical altercation or a fall. The symptoms of a bruised kidney include instant pain, usually centralized to one side of the lower back following an injury, vomiting, nausea and muscle spasms. Someone with a bruised kidney may also notice blood in the urine. A doctor confirms the presence of a kidney contusion via a physical exam or X-ray studies.