A calculus (: calculi), often called a stone, is a

concretion A concretion is a hard and compact mass formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular shapes a ...

of material, usually

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

salts, that forms in an

organ Organ and organs may refer to: Biology * Organ (biology), a group of tissues organized to serve a common function * Organ system, a collection of organs that function together to carry out specific functions within the body. Musical instruments ...

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

gastrolith A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In ...

s, which are ingested rather than grown

endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ...

ly.

Types

thumbnail, Human gallstones, all removed from one patient. Grid scale 1 mm. * Calculi in the

inner ear The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...

are called

otolith An otolith (, ' ear + , ', a stone), also called otoconium, statolith, or statoconium, is a calcium carbonate structure in the saccule or utricle (ear), utricle of the inner ear, specifically in the vestibular system of vertebrates. The saccule ...

s * Calculi in the

urinary system The human urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, urinary bladder, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume ...

are called urinary calculi and include

kidney stone Kidney stone disease (known as nephrolithiasis, renal calculus disease, or urolithiasis) is a crystallopathy and occurs when there are too many minerals in the urine and not enough liquid or hydration. This imbalance causes tiny pieces of cr ...

s (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 Oxalate (systematic IUPAC name: ethanedioate) is an anion with the chemical formula . This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (), and several esters such as ...

and

urate Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the formula C5H4N4O3. It forms ions and salts known as urates and acid urates, such as ammonium acid urate. Uric acid is a product of the metabolic breakdown of ...

. * Calculi in the

prostate The prostate is an male accessory gland, accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemica ...

are called prostatic calculi. * Calculi in the

mammary gland A mammary gland is an exocrine gland that produces milk in humans and other mammals. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in primates (for example, human ...

are called breast microcalcifications or ''mammary microcalcifications''. * Calculi of the

gallbladder In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow Organ (anatomy), organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath t ...

and

bile duct A bile duct is any of a number of long tube-like structures that carry bile, and is present in most vertebrates. The bile duct is separated into three main parts: the fundus (superior), the body (middle), and the neck (inferior). Bile is requ ...

s are called

gallstone A gallstone is a stone formed within the gallbladder from precipitated bile components. The term cholelithiasis may refer to the presence of gallstones or to any disease caused by gallstones, and choledocholithiasis refers to the presence of ...

s and are primarily developed from

bile salts Bile acids are steroid acids found predominantly in the bile of mammals and other vertebrates. Diverse bile acids are synthesized in the liver in peroxisomes. Bile acids are conjugated with taurine or glycine residues to give anions called bile ...

and

cholesterol Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all anima ...

derivatives. * Calculi in the nasal passages (

rhinolith A rhinolith () is a calculus (medicine), stone present in the nasal cavity. It is an uncommon medical phenomenon, not to be confused with dried nasal mucus. A rhinolith usually forms around the nucleus of a small exogenous foreign body, blood clo ...

s) are rare. * Calculi in the

gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the Digestion, digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascula ...

( enteroliths) can be enormous. Individual enteroliths weighing many pounds have been reported in horses. * Calculi in the

stomach The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical t ...

are called gastric calculi (not to be confused with

s which are exogenous in nature). * Calculi in the

salivary gland The salivary glands in many vertebrates including mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands ( parotid, submandibular, and sublingual), as well as hundreds of min ...

s are called salivary calculi ( sialoliths). * Calculi in the tonsils are called tonsillar calculi ( tonsilloliths). * Calculi in the

vein Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and feta ...

s are called venous calculi ( phleboliths). * Calculi in the skin, such as in

sweat gland Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial s ...

s, are not common but occasionally occur. * Calculi in the

navel The navel (clinically known as the umbilicus; : umbilici or umbilicuses; also known as the belly button or tummy button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord. Structure The u ...

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

Cause

* From an underlying abnormal excess of the mineral, e.g., with elevated levels of

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

(

hypercalcaemia Hypercalcemia, also spelled hypercalcaemia, is a high calcium (Ca2+) level in the blood serum. The normal range for total calcium is 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L), with levels greater than 2.6 mmol/L defin ...

) that may cause

s, dietary factors for

s. * 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

. * Enteroliths are a type of calculus found in the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

s of

animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...

s (mostly

ruminant Ruminants are herbivorous grazing or browsing artiodactyls belonging to the suborder Ruminantia that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microb ...

s) and

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

s, and may be composed of

inorganic An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemistry''. Inor ...

or organic constituents. *

Bezoar A bezoar stone ( ) is a mass often found trapped in the gastrointestinal system, though it can occur in other locations. A pseudobezoar is an indigestible object introduced intentionally into the digestive system. There are several varieties o ...

s are lumps of indigestible material in the

and/or intestines; most commonly, they consist of hair (in which case they are also known as

hairball A hairball is a small collection of hair or fur formed in the stomach of animals, and uncommonly in humans, that is occasionally vomiting, vomited up when it becomes too big. Hairballs are primarily a tight elongated cylinder of packed fur, but ...

s). A bezoar may form the nidus of an enterolith. In

kidney stones Kidney stone disease (known as nephrolithiasis, renal calculus disease, or urolithiasis) is a crystallopathy and occurs when there are too many minerals in the urine and not enough liquid or hydration. This imbalance causes tiny pieces of cr ...

calcium oxalate Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula or . It forms hydrates , where ''n'' varies from 1 to 3. Anhydrous and all hydrated forms are colorless or white. The monohydr ...

is the most common mineral type (see nephrolithiasis).

Uric acid Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the Chemical formula, formula C5H4N4O3. It forms ions and salts known as urates and acid urates, such as ammonium acid urate. Uric acid is a product of the meta ...

is the second most common mineral type, but an ''

in vitro ''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in ...

'' study showed uric acid stones and crystals can promote the formation of calcium oxalate stones.

Pathophysiology

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: * Nephrolithiasis (

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

stones) ** Can cause

hydronephrosis Hydronephrosis is the hydrostatic dilation of the renal pelvis and Renal calyx, calyces as a result of obstruction to urine flow downstream. Alternatively, hydroureter describes the dilation of the ureter, and hydronephroureter describes the dila ...

(swollen kidneys) and

kidney failure Kidney failure, also known as renal failure or end-stage renal disease (ESRD), is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney fa ...

** Can predispose to

pyelonephritis Pyelonephritis is inflammation of the kidney, typically due to a bacterial infection. Symptoms most often include fever and flank tenderness. Other symptoms may include nausea, burning with urination, and frequent urination. Complications ...

(kidney infections) ** Can progress to

urolithiasis Kidney stone disease (known as nephrolithiasis, renal calculus disease, or urolithiasis) is a crystallopathy and occurs when there are too many minerals in the urine and not enough liquid or hydration. This imbalance causes tiny pieces of cr ...

Urolithiasis Kidney stone disease (known as nephrolithiasis, renal calculus disease, or urolithiasis) is a crystallopathy and occurs when there are too many minerals in the urine and not enough liquid or hydration. This imbalance causes tiny pieces of cr ...

(

urinary bladder The bladder () is a hollow organ in humans and other vertebrates that stores urine from the Kidney (vertebrates), kidneys. In placental mammals, urine enters the bladder via the ureters and exits via the urethra during urination. In humans, the ...

stones) ** Can progress to bladder outlet obstruction *

Cholelithiasis A gallstone is a stone formed within the gallbladder from precipitated bile components. The term cholelithiasis may refer to the presence of gallstones or to any disease caused by gallstones, and choledocholithiasis refers to the presence of ...

(gallstones) ** Can predispose to

cholecystitis Cholecystitis is inflammation of the gallbladder. Symptoms include Right upper quadrant (abdomen), right upper abdominal pain, pain in the right shoulder, nausea, vomiting, and occasionally fever. Often gallbladder attacks (biliary colic) precede ...

( gall bladder infections) and ascending cholangitis (

biliary tree The biliary tract (also biliary tree or biliary system) refers to the liver, gallbladder and bile ducts, and how they work together to make, store and secrete bile. Bile consists of water, electrolytes, bile acids, cholesterol, phospholipids a ...

infection) ** Can progress to choledocholithiasis (gallstones in the bile duct) and gallstone pancreatitis (inflammation of the

pancreas The pancreas (plural pancreases, or pancreata) is an Organ (anatomy), organ of the Digestion, digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a ...

) * Gastric calculi can cause colic, obstruction, torsion, and

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

Diagnosis

Diagnostic workup varies by the stone type, but in general: * Clinical history and physical examination * Imaging studies: ** Some stone types (mainly those with substantial calcium content) can be detected on

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

and

CT scan A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

** Many stone types can be detected by

ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...

* Factors contributing to stone formation (as in #Etiology) are often tested: **

Laboratory A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratories are found in a variety of settings such as schools ...

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

Modification of predisposing factors can sometimes slow or reverse stone formation. Treatment varies by stone type, but, in general: * Healthy diet and exercise (promotes flow of energy and nutrition) * Drinking fluids (water and

electrolytes An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble salts, acids, and bases, dissolved in a polar solvent like water. Upon dissolving, t ...

like lemon juice, diluted vinegar e.g. in pickles, salad dressings, sauces, soups,

shrubs A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

cocktail) * Surgery ( lithotomy) * Medication /

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...

s * Extracorporeal shock wave lithotripsy (ESWL) for removal of calculi

History

The earliest operation for curing stones is given in the ''

Sushruta Samhita The ''Sushruta Samhita'' (, ) is an ancient Sanskrit text on medicine and one of the most important such treatises on this subject to survive from the ancient world. The ''Compendium of Sushruta, Suśruta'' is one of the foundational texts of ...

'' (6th century BCE). 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 A physician, medical practitioner (British English), medical doctor, or simply doctor is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through the study, diagnosis, prognosis ...

that had taken the Hippocratic Oath because: * There was a high probability of intraoperative and postoperative surgical complications 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 Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

, lime", probably related to Greek ''chalix'' "small stone, pebble, rubble",. which many trace to a

Proto-Indo-European language Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. No direct record of Proto-Indo-European exists; its proposed features have been derived by linguistic reconstruction from documented Indo-Eu ...

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.

References

External links

"The Little Treatise on the Medical Treatment of the Back and of Hemorrhoids"
is a manuscript, from the 18th-century, in Arabic, which discusses the treatment of calculi {{authority control category:medical terminology category:symptoms and signs