Calculus (medicine)
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A calculus is a stone (a concretion of material, usually mineral salts) that forms in an organ or duct of the body. Stones cause a number of important medical conditions.
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[edit] Common stone diseases
A number of important medical conditions are caused by stones:
- Nephrolithiasis (kidney stones)
- Can cause hydronephrosis (swollen kidneys) and renal failure
- Can predispose to pyelonephritis (kidney infections)
- Can progress to bladder stones and bladder outlet obstruction
- Cholelithiasis (gallstones)
- Can predispose to cholecystitis (gall bladder infections) and ascending cholangitis (biliary tree infection)
- Can progress to choledocholithiasis (gallstones in the bile duct) and gallstone pancreatitis (inflammation of the pancreas)
- Rhinolith (nasal calculus)
Stones can also be asymptomatic.
Some common principles (below) apply to stones at any location, but for specifics see the particular stone type in question.
[edit] Aetiology
- From an underlying abnormal excess of the mineral, eg. with elevated levels of calcium (hypercalcaemia) that may cause kidney stones, dietary factors for gallstones.
- 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.
- Bezoars are a type of calculus found in the intestines of mostly ruminant animals and may be composed of inorganic or organic constituents.
[edit] Pathophysiology & 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).
[edit] 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 #Aetiology) 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.
[edit] 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 is sometimes needed.
- Infections due to stones have to be treated with antibiotics and/or surgery.
- Pain is managed with medication.
[edit] See also
- Rhinolith (nasal calculus)
- Salivary duct calculus
- Calculus (dental)