The leading cause of kidney stones is a lack of water in the body. Kidney stones form when your urine contains more crystal-forming substances — such as calcium, oxalate and uric acid — than the fluid in your urine can dilute. At the same time, your urine may lack substances that prevent crystals from sticking together, creating an ideal environment for kidney stones to form.

They take an average of 31 days to pass. Stones that are 4–6 mm are more likely to require some sort of treatment, but around 60 percent pass naturally. This takes an average of 45 days. Stones larger than 6 mm usually need medical treatment to be removed.

Diagnosis of kidney stones is best accomplished using an ultrasound, intravenous pyelography (IVP), or a CT scan. Most kidney stones will pass through the ureter to the bladder on their own with time. Treatment includes pain-control medications and, in some cases, medications to facilitate the passage of urine.

• Treating kidney stones is primarily focused on symptom management. Passing a stone can be very painful.
• If a person has a history of kidney stones, home treatment may be suitable. Individuals who have never passed a kidney stone should speak with a doctor.
• If hospital treatment is needed, an individual may be rehydrated via an intravenous (IV) tube, and anti-inflammatory medication may also be administered.
• Narcotics are often used in an effort to make the pain of passing the stone tolerable. Antiemetic medication can be used in people experiencing nausea and vomiting.
• In some cases, a urologist can perform a shock wave therapy called lithotripsy. This is a treatment that breaks the kidney stone into smaller pieces and allows it to pass.
• People with large stones located in regions that do not allow for lithotripsy may receive surgical procedures, such as removal of the stone via an incision in the back or by inserting a thin tube into the urethra.