What Are the Symptoms and Signs of Kidney Stones?

Medical Author:
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

What is a kidney stone?

A kidney stone is a small stone, usually made up of calcium crystals, that forms inside the part of the kidney where urine collects. The stone usually causes little problem until it falls into the ureter, the tube that drains the kidney into the bladder, and causes an obstruction, preventing urine from draining out of the kidney and often causing severe pain.

One of the roles of the kidney is to remove waste from the body by filtering blood and making urine. That urine flows from the kidney into the bladder through the ureter, a thin tube that connects the two. The bladder empties through the urethra, a tube much wider than the ureter.

A variety of minerals and chemicals are excreted in the urine and sometimes these combine to form the beginning of a stone. Over time, this can grow from an invisible speck of sand into a stone that can be an inch in diameter or larger.

There are different terms for kidney stones depending upon where they are located within the urinary tract:

  • Urolith: A stone anywhere within the urinary tract
  • Nephrolith: A stone within the kidney
  • Ureterolith: A stone within the ureter
  • Calculus: A stone within the body

What are the different types of kidney stones?

Calcium oxalate is by far the most common type of kidney stone. Less frequently, uric acid can cause stones. (This is the same chemical compound that is the cause of gout.) Struvite, xanthine, and other types of stones are rare. Some stones are combinations of these minerals and chemicals.

What are the signs and symptoms of kidney stones?

What Are the Symptoms and Signs of Kidney Stones? Resources

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Medically Reviewed by a Doctor on 9/26/2013