Picture: Kidney stones are hard crystallized salts and minerals in the urine that can cause blood in the urine and severe pain.
Kidney Stone

Kidney Stones
(Renal Stones, Nephrolithiasis)

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Kidney stone facts

  • A kidney stone is a hard, crystalline mineral material formed within the kidney or urinary tract.
  • Nephrolithiasis is the medical term for kidney stones.
  • Symptoms of a kidney stone include flank pain (which can be quite severe) and blood in the urine (hematuria).
  • Kidney stones form when there is a decrease in urine volume and/or an excess of stone-forming substances in the urine.
  • Dehydration is a major risk factor for kidney stone formation.
  • People with certain medical conditions, such as gout, and those who take certain medications or supplements are at risk for kidney stones.
  • Dietary and hereditary factors are also related to stone formation.
  • Diagnosis of kidney stones is best accomplished using 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.
  • If needed, lithotripsy or surgical techniques may be used for stones which do not pass through the ureter to the bladder on their own.

What is a kidney stone?

A kidney stone is a hard, crystalline mineral material formed within the kidney or urinary tract. Kidney stones are a common cause of blood in the urine (hematuria) and often severe pain in the abdomen, flank, or groin. Kidney stones are sometimes called renal calculi.

The condition of having kidney stones is termed nephrolithiasis. Having stones at any location in the urinary tract is referred to as urolithiasis, and the term ureterolithiasis is used to refer to stones located in the ureters.

Reviewed by William C. Shiel Jr., MD, FACP, FACR on 2/1/2013


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Learn about the signs, symptoms, causes, and treatment of kidney stones.

The Agony of Kidney Stones

One Patient's Story

Reviewed by William Shiel Jr., MD, FACP, FACR

It all started on a typical Maui fall day, with beautiful trade winds and sunny skies over the Kapalua Golf Course. Tom Stokes* and his wife Teresa* were about to start the ninth hole when Tom had to go to the bathroom.

"I was standing over the urinal and noticed blood in my urine," Stokes says.

Confused as to what he should do, Stokes decided to just finish playing golf without mentioning anything to his wife.

"Needless to say, I didn't have a good score from that point on," he says.

Back at the hotel he was still urinating blood, but decided it could wait until he returned home to California the following day.

"There were no other symptoms," he says. "No pain, no other indications."

Upon returning to California, Stokes went to see a urologistwho asked him to have a kidney ureterbladder(KUB) x-raydone, which documented that he had a kidney stone.

Stokes' stone was so big it couldn't pass from the kidney to the ureter (the tube from the kidney to the bladder). The stone was approximately 8 mm, while the average inner diameter of the ureter is 4 mm.

*Names have been changed.

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