A calculus (pl.: 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 (/ˌlɪˈθaɪəsɪs/). 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 in the urinary system are called urinary calculi and include kidney stones (also called renal calculi or nephroliths) and bladder stones (also called vesical calculi or cystoliths). They can have any of several compositions, including mixed. Principal compositions include oxalate and urate.
From an underlying abnormal excess of the mineral, e.g., 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 lumps of indigestible material in the stomach and/or intestines; most commonly, they consist of hair (in which case they are also known as hairballs). 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.[1]
Pathophysiology
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]
Extracorporeal shock wave lithotripsy (ESWL) for removal of calculi
History
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]
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
Etymology
The word comes from Latin calculus "small stone", from calx "limestone, lime",[3] probably related to Greek χάλιξchalix "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]