Calculus (medicine)

A calculus (plural calculi), often called a stone, is a concretion of material, usually mineral salts, that forms in an organ or duct of the body. Formation of calculi is known as lithiasis (/ˌlɪˈθəsɪs/). Stones can cause a number of medical conditions.

Other namesStone
An 8-mm kidney stone
TreatmentDrinking water, surgery

Some common principles (below) apply to stones at any location, but for specifics see the particular stone type in question.

Calculi are not to be confused with gastroliths.


Human gallstones, all removed from one patient. Grid scale 1 mm.

Calculi are usually asymptomatic, and large calculi may have required many years to grow to their large size.


In kidney stones, calcium oxalate is the most common mineral type (see Nephrolithiasis). Uric acid is the second most common mineral type, but an in vitro study showed uric acid stones and crystals can promote the formation of calcium oxalate stones.[1]


Stones can cause disease by several mechanisms:[citation needed]

  • Irritation of nearby tissues, causing pain, swelling, and inflammation
  • Obstruction of an opening or duct, interfering with normal flow and disrupting the function of the organ in question
  • Predisposition to infection (often due to disruption of normal flow)

A number of important medical conditions are caused by stones:[citation needed]


Diagnostic workup varies by the stone type, but in general:[citation needed]

  • Clinical history and physical examination
  • Imaging studies
    • Some stone types (mainly those with substantial calcium content) can be detected on X-ray and CT scan
    • Many stone types can be detected by ultrasound
  • Factors contributing to stone formation (as in #Etiology) are often tested:
    • Laboratory testing can give levels of relevant substances in blood or urine
    • Some stones can be directly recovered (at surgery, or when they leave the body spontaneously) and sent to a laboratory for analysis of content


Modification of predisposing factors can sometimes slow or reverse stone formation. Treatment varies by stone type, but, in general:[citation needed]


The earliest operation for curing stones is given in the Sushruta Samhita (6th century BCE).[2] The operation involved exposure and going up through the floor of the bladder.[2]

The care of this disease was forbidden to the physicians that had taken the Hippocratic Oath[citation needed] because:

  • There was a high probability of intraoperative and postoperative surgical complication like infection or bleeding
  • The physicians would not perform surgery as in ancient cultures they were two different professions


The word comes from Latin calculus "small stone", from calx "limestone, lime",[3] probably related to Greek χάλιξ chalix "small stone, pebble, rubble",[4] which many trace to a Proto-Indo-European root for "split, break up".[5] Calculus was a term used for various kinds of stones. In the 18th century it came to be used for accidental or incidental mineral buildups in human and animal bodies, like kidney stones and minerals on teeth.[5]

See alsoEdit


  1. ^ Grases F.; Sanchis P.; Isern B.; Perelló J.; Costa-Bauzá A. (2007). "Uric Acid as Inducer of Calcium Oxalate Crystal Development". Scandinavian Journal of Urology and Nephrology. 41 (1): 26–31. doi:10.1080/00365590600831571. PMID 17366099.
  2. ^ a b Lock, Stephen etc. (2001). The Oxford Illustrated Companion to Medicine. USA: Oxford University Press. 836. ISBN 0-19-262950-6.
  3. ^ calx. Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project.
  4. ^ χάλιξ. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.
  5. ^ a b Harper, Douglas. "calculus". Online Etymology Dictionary. Harper, Douglas. "chalk". Online Etymology Dictionary.

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