Calculus (medicine)
A calculus (plural calculi) is a stone (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 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 gastroliths.
Types of lithiasis
- Calculi in the renal system (kidneys, ureters, urinary bladder, urethra) can be of any one of several compositions, including mixed. Principal compositions include oxalate and urate.
- Calculi in the nasal passages (rhinoliths) are rare.
- Calculi in the gastrointestinal tract (enteroliths) can be enormous. Individual enteroliths weighting many pounds have been reported in horses.
- Salivary duct calculus
- Tonsillolith
Calculi usually are asymptomatic, and large calculi may have required many years to grow to their large size.
Etiology
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[1] shows that uric acid stones and crystals can promote the formation of calcium oxalate stones.
Pathophysiology and symptoms
Stones can cause disease by several mechanisms:
- 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:
Diagnosis
Diagnostic workup varies by the stone type, but in general:
- Clinical history and physical examination can be sufficient in some cases.
- Imaging studies are often needed.
- 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.
Treatment
Again, treatment varies by stone type, but in general:
- Modification of predisposing factors can sometimes slow or reverse stone formation.
- Medications can sometimes be used.
- Surgery (lithotomy) is sometimes needed.
- Infections due to stones have to be treated with antibiotics and/or surgery.
- Pain is managed with medication.
- Calculi may be removed by a method known as electro sound waves lithotripsy (ESWL).
History
The earliest operation for curing stones is also given in the Sushruta Samhita (6th century BCE).[2] The operation involved exposure and going up through the floor of the bladder.[2]
See also
References
- ^ 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.
- ^ a b Lock, Stephen etc. (2001). The Oxford Illustrated Companion to Medicine. USA: Oxford University Press. 836. ISBN 0192629506.
External links