Kidney Stones 101

Kidney stones are small pieces of hard, crystallized material that form in the kidney. Kidney stones are often made up of calcium, but can also contain uric acid or amino acids (proteins). Kidney stones, also called renal lithiasis, are a common condition.

What are the symptoms of kidney stones?

Small kidney stones or kidney stones that do not move and remain in the kidney may not produce any symptoms. A small kidney stone may pass in the urine out of the body without causing pain or visible blood in the urine.

When a large kidney stone moves out of the kidney and into the ureter, it generally causes severe, sharp and stabbing pain in the flank area of the lower back. This is called renal colic. Renal colic often comes in waves of severe pain that can be accompanied by profuse sweating, restlessness, irritability, nausea and vomiting.

As a kidney stone moves down the ureter toward the bladder, the pain can move from the flank area to the lower abdominal area and into the groin. Pain may also radiate into the testicles or the labia. If the kidney stone is able to pass into the bladder, the pain usually resolves. Once in the bladder, a kidney stone generally is able to move easily out of the bladder, into the urethra, and out of the body during urination.

Symptoms that might indicate a serious condition

Kidney stones can be extremely painful and lead to serious complications, such as kidney infection and kidney damage. Seek immediate medical care if you, or someone you are with, have any symptoms of passing a kidney stone including:

• Bloody or pink-colored urine (hematuria)
• Dark or tea-colored urine
• Difficult urination or lack of urination
• Irritability
• Nausea and vomiting
• Restlessness
• Severe flank pain that can move or radiate to the lower abdomen, groin, labia, or testicles
• Sweating
  
  

  What are the risk factors for kidney stones?

  A number of factors increase the risk of developing kidney stones. Risk factors include:
  • Dehydration, including long-term mild dehydration, which results in the production of smaller amounts of urine that contain a higher concentration of substances that form kidney stones, such as calcium and amino acids
  • Gout (type of arthritis caused by a buildup of uric acid in the joints)
  • High-protein diet
  • Hypertension (high blood pressure)
  • Male gender
  • Obesity
  • Personal or family history of kidney stones or certain kidney defects, such as horseshoe kidney
  • Prolonged exposure to a hot climate or high altitudes. People living in these areas lose more body water and produce smaller amounts of urine that contains a higher concentration of substances that form kidney stones, such as calcium and amino acids.
  • Prolonged inactivity, such as being bedridden
  • Urinary tract infection

    General treatment of kidney stones

    General treatment of kidney stones includes:
    • Drinking fluids to dilute the urine and help flush out a kidney stone
    • Pain medications, which, for large stones, may be given intravenously by emergency care providers

    Surgical treatment of kidney stones

    If a kidney stone does not pass out of the body with fluids and pain medications, it may have become lodged in the ureter. A variety of procedures may be considered to remove the stone. These include:
    • Cystoscopy, in which specialized instruments are passed into the ureter through the bladder to withdraw a kidney stone that has become lodged in the lower third of the ureter. A similar procedure may be used to remove or crush the kidney stone using a laser or ultrasonic probe.
    • Extracorporeal shock wave lithotripsy, a procedure that is performed for a kidney stone located in the upper ureter or in the kidney. In this procedure, the kidney stone is crushed by a machine using high-energy sound waves (also known as shock waves).
    In rare cases in which kidney damage has occurred, it may be necessary to remove the affected kidney. This is called a nephrectomy.