Some injuries can bruise your kidney. These include automobile accidents, falls, assaults, and injuries from contact sports. A kidney bruise may cause blood to appear in your urine. The blood may be in small amounts that you can't see. Or it might color your urine pink or light red. Any blood often clears in 1 to 2 days and the kidney function returns to normal. Call your healthcare provider if the blood does not clear from your urine after 2 days.
These are signs and symptoms of a bruised kidney:
Blood in the urine
Pain in the area between your hip and ribs (flank pain)
Bruising, swelling, or seatbelt marks in the area of your kidney or low back
If you've had a bruise to your kidney, follow these tips:
Drink lots of fluid. This means at least 8 to 10 glasses of water a day.
Rest. Don't lift heavy objects or do strenuous activity for the next few days.
You may use over-the-counter medicine to control pain, unless your healthcare provider prescribed something else. Talk with your provider before using acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) such as naproxen or ibuprofen if you have chronic liver or kidney disease. Also talk with your provider if you've ever had a stomach ulcer or gastrointestinal bleeding. Aspirin should never be used in anyone under 18 years of age who is ill with a fever. This may cause a life-threatening condition called Reye syndrome.
Follow up with your healthcare provider if you're still having blood in your urine after 2 days (48 hours).
Fainting, lightheadedness, dizziness, weakness, or loss of consciousness
Rapid heart rate
Severe belly (abdominal) pain or swelling
Severe back pain
Loss of feeling or weakness in your legs
Can't hold your urine (incontinence)
Call your healthcare provider right away if any of these occur:
Back or belly pain that gets worse
Increasing amount of blood color in the urine
Passage of blood clots in the urine
Unable to pass urine
Fever of 100.4°F (38ºC) or higher, or as advised by your provider