kidney stone

an abnormal stone, or concretion, composed primarily of oxalates and phosphates, found in the kidney. Also called renal calculus.
[1970-75]

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Mass of minerals and organic matter that may form in a kidney.

Urine contains many salts in solution, and low fluid volume or high mineral concentration can cause these salts to precipitate and grow, forming stones. Large stones can block urine flow, be a focus for infection, or cause renal colic (painful spasms). They can obstruct the urinary system at various points. Treatment deals with any underlying problem (e.g., infection or obstruction), tries to dissolve stones with drugs or ultrasound (lithotripsy), or removes large ones surgically.

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▪ medical disorder
also called  renal calculus,  plural  renal calculi,  

      concretion of minerals and organic matter that forms in the kidneys. Such stones may become so large as to impair normal renal function. Urine contains many salts in solution, and if the concentration of mineral salts becomes excessive, the excess salt precipitates as crystals that may enlarge to become visible, solid particles called stones. Kidney stones are classified as primary if they form without apparent cause, such as an infection or obstruction. They are classified as secondary if they develop after a renal infection or disorder.

      Certain circumstances increase the likelihood of stone formation. Either a reduction in fluid volume or a surge in mineral concentration can be enough to upset the delicate balance between the liquid and its solutes. An increase in mineral concentration in the kidneys may occur because of metabolic conditions or infections. Once a stone starts developing, it generally continues to grow. A nucleus for precipitation of urinary salts can be a clump of bacteria, degenerated tissue, sloughed-off cells, or a tiny blood clot. Minerals start collecting around the foreign particle and encrusting it. As the stone increases in size, the surface area available for additional mineral deposition is continually increased.

      Kidney stones, if large, can obstruct the outflow of urine, allow infections to persist, and create spasms in the renal tubules, a condition known as renal colic. In renal colic there is generally severe pain leading from the kidneys down through the abdomen and groin. Stones may cause obstruction in the renal pelvis (the funnel-like structure at which the kidney joins the ureter), in a ureter (the tube that carries urine from the kidney to the bladder), or in the bladder.

      Many persons with kidney stones fail to show distinct symptoms. Others, however, can have severe kidney pain, infection, and inflammation. The most severe pain occurs where the passage of urine from the kidney is obstructed by the stone. Treatment includes medications to clear up infections and to relieve pain. Some stones may dissolve, and most stones pass without active intervention. Large stones that fail to dissolve are removed by surgery.

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Universalium. 2010.

Look at other dictionaries:

  • Kidney stone — Kidney Kid ney (k[i^]d n[y^]), n.; pl. {Kidneys} (k[i^]d n[i^]z). [OE. kidnei, kidnere, from Icel. koi[eth]r belly, womb (akin to Goth. gipus, AS. cwi[thorn] womb) + OE. nere kidney; akin to D. nier, G. niere, OHG. nioro, Icel. n[=y]ra, Dan. nyre …   The Collaborative International Dictionary of English

  • kidney stone — n. a hard mineral deposit sometimes formed in the kidney from phosphates, urates, etc.; renal calculus …   English World dictionary

  • kidney stone — ► NOUN ▪ a hard mass formed in the kidneys, typically consisting of insoluble calcium compounds …   English terms dictionary

  • Kidney stone — Classification and external resources …   Wikipedia

  • Kidney stone — 1. A stone in the kidney (or lower down in the urinary tract). Kidney stones are a common cause of blood in the urine and pain in the abdomen, flank, or groin. Kidney stones occur in 1 in 20 people at some time in their life. The development of… …   Medical dictionary

  • kidney stone — Renal calculus Renal calculus (Med.), an abnormal concretion formed in the excretory passages of the kidney, composed primarily of calcium oxalates and phosphates; also called {kidney stone}, {nephrolith}, and {nephritic calculus} (an obsolete… …   The Collaborative International Dictionary of English

  • kidney stone — noun a calculus formed in the kidney • Syn: ↑urinary calculus, ↑nephrolith, ↑renal calculus • Hypernyms: ↑calculus, ↑concretion * * * noun, pl ⋯ stones [count] medical : a hard object like a small stone that sometimes forms in …   Useful english dictionary

  • kidney stone — kid′ney stone n. pat a stony mineral concretion formed abnormally in the kidney • Etymology: 1945–50 …   From formal English to slang

  • kidney stone — noun A calculus in the kidney; (older term) kidney gravel …   Wiktionary

  • kidney stone — noun Date: 1874 a calculus (as of calcium salts) in the kidney …   New Collegiate Dictionary

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