Kidney stones (also called nephrolithiasis or urolithiasis) affect approximately 12 percent of men and 5 percent of women by age 70. Fortunately, treatment is available to effectively manage most stones. In addition, you can take steps to prevent kidney stones from coming back again.
How does a kidney stone form? A kidney stone can form when some of the substances naturally in your body such as calcium, oxalate, cystine, or uric acid are at high levels in the urine. Stones can also form if these substances are at normal levels. The substances form crystals, which in the kidney can gradually increase in size, forming a kidney stone.
Typically, the stone will move through the urinary tract and is passed out of the body in the urine. A stone may cause pain if it becomes stuck and blocks the flow of urine. Large stones do not always pass on their own and sometimes require a procedure or surgery to remove them.
Symptoms can include:
- Pain — Pain is the most common symptom of kidney stones. For those who have had pain from kidney stones, you already know the type and amount of pain that kidney stones can cause. Pain can range from a mild and barely noticeable ache to discomfort that is so intense it requires treatment in the hospital. Typically, the pain gets worse and better, but does not go away completely. Waves of severe pain, known as renal colic, usually last 20 to 60 minutes. Pain can occur in the flank (the side, between the ribs and the hip) or the lower abdomen.
- Blood in the urine — Most people with kidney stones will have blood in the urine (hematuria). The urine may be pink or reddish, or the blood may be visible only with urine dipstick testing or microscopic examination of the urine.
- Other symptoms — Other kidney stone symptoms include nausea or vomiting, pain with urination, and an urgent need to urinate.
Test that may be performed:
- Computed tomography (CT) scan — A CT scan creates a three dimensional image of structures within the body. A particular type of CT scan (called noncontrast CT) is often recommended if kidney stones are suspected.
- Ultrasound — An ultrasound can also be used to detect kidney stones, although small stones or stones in the ureters may be missed. However, ultrasound is the procedure of choice for people who should avoid radiation, including pregnant women.
Kidney stone treatment will vary depending on your symptoms and situation. There are times that your doctor may tell you that you can be treated with medications at home. If this does not work, you have an infection, or your stone is too large to pass on its own then there are other treatments that may need to be done
- Shock wave lithotripsy (ESWL) — Lithotripsy is the treatment of choice in many patients who need help passing a stone using high energy shock waves to break up your stone through the skin. Lithotripsy is particularly good for stones in the kidney and upper ureter. Lithotripsy may not be effective for treating large or hard stones.
- Ureteroscopy — Ureteroscopy is a procedure that uses a thin scope, which is passed through the urethra and bladder, into the ureter and kidney. This scope contains a camera and other instruments, which allows the physician to see the stone and remove it, or to break it up into smaller pieces that can pass more easily. Ureteroscopy is often used to remove stones blocking the ureter, and sometimes for stones in the kidney.
- Percutaneous nephrolithotomy (PNL) — Extremely large or complex stones, or stones resistant to shock wave lithotripsy, may require a minimally invasive surgical procedure to remove the stone. In this procedure, small instruments are passed through the skin (percutaneously) into the kidney to remove the stone.