The kidney is most likely to be injured by direct impact, directly beneath the ribs (e.g. with cleats), or by squeezing (e.g. during a traffic accident). This may cause kidney contusion, or tearing of his outer membrane and ureter.
Sometimes a large blood clot forms beneath the membrane, forming a bump (over the kidney) that you can feel through the skin if it is located on the lower part of the kidney. There is also a possibility (and a danger) of blood or urine flow into the abdominal cavity, which will cause peritonitis. If the internal part of the kidney is damaged, the blood will pass into the urine.
Mild kidney or ureteral injuries can cause pain or sensitivity in the lower part of the backs. A slight fever is also possible. Occasionally, traces of blood may appear in the urine, but usually a day or two after the injury. If you had an accident, and if you feel strong back pain or notice blood in the urine, it is possible that you may have seriously injured one or both kidneys, and possibly ureter. In any case, contact your doctor.
Blood in the urine is a symptom of a possible serious condition and should never be neglected. You will probably need to take X-rays of kidneys, i.e. take the intravenous pyelogram (IVP), so that the physician can assess the damage and determine the required therapy.
Kidneys and ureter have a remarkable healing abilities, and even large scarring and injuries rarely require treatment after 7 to 10 days of rest. However, if the IVP shows that the injury is serious, the injured person is usually advised to rest at the hospital where he will receive pain medications with frequent pulse and blood pressure control. After about 3 months, another scan (IVP) is recommended to exclude the possibility of permanent kidney or ureter damage.
If the problems are still present after a week of resting (which is unlikely), it may be necessary to surgically remove the kidney or restore the damaged ureter. Kidney removal is usually not a complicated operation, and the patients can continue to lead a healthy and normal life with only one kidney.