This can result in blood in the urine.
Asymptomatic microscopic hematuria has many causes, ranging from minor incidental findings that do not require treatment to highly significant lesions that are immediately life-threatening.
Note tiny right renal calculus short arrow.
It may be linked to trauma to the bladder, dehydration or the breakdown of red blood cells that occurs with sustained aerobic exercise.
Bleeding disorders or certain medications also may cause it.
Idiopathic hematuria can run in families, and is called familial idiopathic hematuria.