Kidney stone and ureter (tube which joins kidney and bladder for urine flow) stones are the commonest cause for your kind of symptoms. The stone erode the internal lining of the ureter or kidney and thus the blood in urine. An x-ray and ultrasound are diagnostic of the stone. Usually a small stone less than 6 mm will pass spontaneously. Bigger stone will need some sort of surgical treatment or ESWL, in which ultrasound waves break stones from outside. The other causes for blood in urine are;
1) Some growth, cyst in urinary tract
2) Urinary tract infection
3) Bleeding disorders
Please read this resource on blood in urine;
Please feel free for your follow up questions.
As I mentioned, the assessment of the size is important by x-ray and an ultrasound, for the management decision. These investigations, gives an idea of not only the size but also the position in the urinary tract (in the kidney calyx, kidney pelvis, upper ureter, middle ureter etc). A bigger the stone size and upper the position; more the time would be needed for the passing out of the stone. Drinking more water, drinking Cranberry juice, avoiding alcohol and caffeine drinks are some of the conservative measures, which will help in early passage. If the urine examination shows some bacteria in urine an antibiotic is started (usually infection occurs in the presence of the stone). The antibiotic helps in the symptoms, especially the pain.
If the stone size is more than 6 mm, some sort of intervention is planned as above measures are not likely to benefit.
The urine color changes because the bleeding is intermittent by a stone (not continuous).
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