Kidney stones are crystal deposits from urine that build up to form a solid stone. They usually form silently in the kidneys and often do not cause symptoms until they start to pass from the kidneys to the bladder. As they pass, they may cause abdominal, loin or back pain, nausea, urinary frequency, and blood in the urine.
The diagnosis of kidney stones is usually made on a CT scan. Most of the time, kidney stones pass through spontaneously with adequate pain relief, but if they are large, the pain is persistent and severe, or if they cause a significant blockage with infection, then treatment may be necessary.