Kidney Stones (Renal Calculi)

What are kidney stones (renal calculi)?

Kidney stones, also called renal calculi, are solid pieces of material that form in the kidneys from substances in the urine. Stones can occur in any part of the urinary system from the kidneys to the bladder. They may be small or large. You may have just one stone or many.

There are different types of kidney stones:

• Calcium stones: Most kidney stones are calcium stones. Many people have calcium stones from too much of a chemical called oxalate in their diet. Oxalate is in many foods, such as spinach, rhubarb, leafy vegetables, coffee, chocolate, and tomatoes. You may also get calcium stones when there is too much calcium in your urine. This may happen when your kidneys don't work properly or your stomach and intestines absorb too much calcium.
• Uric acid stones: Uric acid stones happen when you have too much uric acid in your urine. This might happen when your body does not have enough fluid, such as when you exercise on a hot day or during an illness and you don’t drink enough fluids.
• Struvite stones: This type of stone is also called an infection stone because it forms in urine that is infected with bacteria.
• Cystine stones. This type of kidney stone is rare. It happens if you have a genetic disease called cystinuria. This disease results from a birth defect that causes the kidney to let too much cystine into the urine.

What can I expect in the hospital?

You may need to stay in the hospital if:

• Pain cannot be controlled by oral medicines
• You are vomiting too much to drink liquids
• You have signs of infection, such as fever, chills or a high white blood cell count
• You need surgery to remove a stone that is not passing and is causing severe problems

Several things may be done while you are in the hospital to monitor, test, and treat your condition. They include:

Monitoring

• You will be checked often by the hospital staff.
• Your heart rate, blood pressure, and temperature will be checked regularly.
• Your blood oxygen level may be monitored by a sensor that is attached to your finger or earlobe.
• You may be asked to collect and strain your urine. This will allow your provider to check the size and type of stones that you have.
• You may have a small tube (catheter) placed into your bladder to drain and measure urine.

Testing

Your healthcare provider will ask about your medical history and symptoms, and perform a physical exam. Testing may include:

• Blood tests to check for infections
• Urine tests to check for blood, stones, or infections
• Tests to look for the position of any stones and abnormalities of the urinary tract, which may include:
  • Computed tomography (CT) scan: A series of X-rays is taken from different angles and arranged by a computer to show thin cross sections of the kidneys and urinary structures.
  • X-rays: Pictures of the inside of the kidneys and urinary structures to check for stones, blockages, or other abnormalities
  • Intravenous pyelography (IVP): An X-ray is taken after an injection of contrast dye into a vein to help your provider see the location of stones or blockages as the contrast dye moves through the kidneys and urinary structures.
  • Ultrasound scan: Sound waves and their echoes are passed through the body from a small device that is held against your skin to create pictures of the inside of the kidneys and urinary structures.

Treatment

Treatment depends on the size and location of the stones, whether the urine flow out of a kidney is blocked, and whether there are signs of infection. Treatment may include:

• You will have a small tube (IV catheter) inserted into a vein in your hand or arm. This will allow for medicine to be given into your blood system and to give you fluids, if needed.
• Your provider may prescribe medicine to:
  • Treat pain
  • Treat or prevent an infection
  • Reduce swelling in the urinary tract
  • Treat or prevent nausea
• Your provider may recommend other types of therapy to help relieve pain, other symptoms, or side effects of treatment.
• Your healthcare provider may recommend that you drink larger quantities of fluids to help you pass kidney stones and change your diet to help prevent future stones.
• Extracorporeal shock wave lithotripsy (ESWL): A procedure in which ultrasound shock waves are used to break the stones into small pieces. It is then possible to pass the smaller pieces of the stones in your urine. In most cases, you will be given anesthesia to prevent pain during the procedure.
• You may need surgery to remove a kidney stone if it is large, blocking the flow of urine, or causing an infection. This may include:
  • Ureteroscopy: A procedure in which a thin, lighted, usually flexible tube called an ureteroscope is passed through the urethra into the urinary tract. Tools can be passed through the scope to trap and remove the stone using special baskets. This may be done with shock wave or laser lithotripsy to break up larger stones and make them easier to remove.
  • Percutaneous nephrolithotomy or nephrolithotripsy (PNL): A procedure in which your healthcare provider makes a small cut in your back and a narrow tunnel through the skin into the kidney. With a scope that goes through the tunnel, your provider can find and remove the stone or break it into small pieces using either laser or ultrasound lithotripsy.
  • Ureteral stent: A procedure in which your healthcare provider places a tube called a stent in the ureter to allow urine to drain from your kidney into your bladder.
  • Nephrostomy is a procedure in which a small tube is placed through a small cut on your back. It will allow urine to drain out of your kidney. The tube may be attached to a drainage bag or connect your kidney to your bladder.

What can I do to help?

• You will need to tell your healthcare team if you have new or worsening:
  • Back or belly pain
  • Burning with urination
  • Blood in your urine
  • Passing gravel-like or sand-like stones in the urine
  • Nausea or vomiting
  • Redness, swelling, pain, warmth, or drainage from your surgical wound
  • Fever, chills, or muscle aches
• Ask questions about any medicine or treatment or information that you do not understand.

How long will I be in the hospital?

How long you stay in the hospital depends on many things, such as your general health, why you are in the hospital, and the treatment you need. The average amount of time to stay in the hospital with kidney stones is 2 to 3 days. Talk with your provider about how long your stay may be.