A calculus (: 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 (). Stones can cause a number of medical conditions.
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 , which are ingested rather than grown .
Types
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Calculi in the inner ear are called a
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Calculi in the urinary system are called urolithiasis and include kidney stones (also called renal calculi or nephroliths) and (also called vesical calculi or cystoliths). They can have any of several compositions, including mixed. Principal compositions include oxalate and urate.
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Calculi in the prostate are called prostatic calculi.
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Calculi in the mammary gland are called breast microcalcifications or mammary microcalcifications.
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Calculi of the gallbladder and are called and are primarily developed from bile acid and cholesterol derivatives.
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Calculi in the nasal passages () are rare.
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Calculi in the gastrointestinal tract () can be enormous. Individual enteroliths weighing many pounds have been reported in horses.
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Calculi in the stomach are called gastric calculi (not to be confused with which are exogenous in nature).
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Calculi in the are called salivary calculi (sialolithiasis).
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Calculi in the are called tonsillar calculi ().
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Calculi in the are called venous calculi ().
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Calculi in the skin, such as in , are not common but occasionally occur.
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Calculi in the navel are called .
a Note that unlike other entries in this list, otoliths are not pathological but are a normal feature of the inner ear[Shier D, Butler J, Lewis R. Hole's human anatomy and physiology, 11th ed. Boston: McGraw-Hill, 2007.].
Calculi are usually asymptomatic, and large calculi may have required many years to grow to their large size.
Cause
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From an underlying abnormal excess of the mineral, e.g., with elevated levels of calcium (hypercalcaemia) that may cause , dietary factors for .
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Local conditions at the site in question that promote their formation, e.g., local bacteria action (in kidney stones) or slower fluid flow rates, a possible explanation of the majority of salivary duct calculus occurring in the submandibular salivary gland.
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are a type of calculus found in the of (mostly ) and , and may be composed of inorganic or Biotic material constituents.
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are lumps of indigestible material in the stomach and/or intestines; most commonly, they consist of hair (in which case they are also known as ). A bezoar may form the nidus of an enterolith.
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.
Pathophysiology
Stones can cause disease by several mechanisms:
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Irritation of nearby tissues, causing pain, swelling, and inflammation
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Obstruction of an opening or duct, interfering with normal flow and disrupting the function of the organ in question
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Predisposition to infection (often due to disruption of normal flow)
A number of important medical conditions are caused by stones:
Diagnosis
Diagnostic workup varies by the stone type, but in general:
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Clinical history and physical examination
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Imaging studies:
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Some stone types (mainly those with substantial calcium content) can be detected on X-ray and CT scan
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Many stone types can be detected by ultrasound
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Factors contributing to stone formation (as in #Etiology) are often tested:
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Laboratory testing can give levels of relevant substances in blood or urine
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Some stones can be directly recovered (at surgery, or when they leave the body spontaneously) and sent to a laboratory for analysis of content
Treatment
Modification of predisposing factors can sometimes slow or reverse stone formation. Treatment varies by stone type, but, in general:
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Healthy diet and exercise (promotes flow of energy and nutrition)
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Drinking fluids (water and electrolytes like lemon juice, diluted vinegar e.g. in pickles, salad dressings, sauces, soups, shrubs cocktail)
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Surgery (lithotomy)
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Medication /
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Extracorporeal shock wave lithotripsy (ESWL) for removal of calculi
History
The earliest operation for curing stones is given in the
Sushruta Samhita (6th century
Common Era).
[ The operation involved exposure and going up through the floor of the bladder.][Lock, Stephen etc. (2001). The Oxford Illustrated Companion to Medicine. USA: Oxford University Press. 836. .]
The care of this disease was forbidden to the physicians that had taken the Hippocratic Oath because:
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There was a high probability of intraoperative and postoperative surgical complications like infection or bleeding
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The physicians would not perform surgery as in ancient cultures they were two different professions
Etymology
The word comes from Latin calculus "small stone", from calx "limestone, lime",[.] which many trace to a Proto-Indo-European language root for "split, break up".[ ] 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.
See also
External links
