What it means
Kidney stones form when minerals in urine, most often calcium, clump into crystals and grow. They range from grains of sand to a few centimeters. A stone can sit quietly in the kidney or move into the ureter, the thin tube that drains urine to the bladder. CT without contrast shows almost all stones. Reports give the size and location, and say whether urine flow is blocked.
When it matters
Small stones in the kidney often cause no symptoms and are found by chance. A stone moving down the ureter can cause sudden, severe pain in the side or back (renal colic) and blood in the urine. Stones under about 5 mm usually pass on their own, while larger ones are less likely to. A blocked kidney with fever needs urgent care. Your doctor may suggest waiting, medicine to help a stone pass, or a procedure.
Questions to ask your doctor
- How big is the stone, and is it likely to pass on its own?
- Is the stone blocking urine flow from the kidney?
- Should my urine or blood be tested to help prevent new stones?
Read more: Kidney Stones on CT and Ultrasound: Causes, Symptoms, and Treatment
