# Enterolith

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Solid mineral mass formed in the gastrointestinal system

For other uses, see [calculus (medicine)](/source/Calculus_(medicine)).

Medical condition

Enterolith Specialty Gastroenterology

An **enterolith** is a mineral [concretion](/source/Concretion) or [calculus](/source/Calculus_(medicine)) formed anywhere in the [gastrointestinal system](/source/Gastrointestinal_system). Enteroliths are uncommon and usually incidental findings but, once found, they require at a minimum [watchful waiting](/source/Watchful_waiting). If there is evidence of complications, they must be removed. An enterolith may form around a *nidus*, a small [foreign object](/source/Foreign_body) such as a seed, pebble, or piece of twine that serves as an irritant. In this respect, an enterolith forms by a process similar to the [creation of a pearl](/source/Pearl#Creation). An enterolith is not to be confused with a [gastrolith](/source/Gastrolith), which helps digestion.

## In equines

[Equine](/source/Equine) enteroliths are found by walking pastures or turning over manure compost piles to find small enteroliths, during [necroscopy](/source/Necroscopy), and increasingly, during surgery for [colic](/source/Colic). Therefore, the incidence of asymptomatic enteroliths is unknown.

Equine enteroliths are typically smoothly spherical or tetrahedral,[1] consist mostly of the mineral [struvite](/source/Struvite)[1][2] ([ammonium](/source/Ammonium) [magnesium](/source/Magnesium) [phosphate](/source/Phosphate)), and have concentric rings of mineral precipitated around a nidus.[1][3]

Enteroliths in [horses](/source/Horse) were reported widely in the 19th century, infrequently in the early 20th century, and now increasingly. They have also been reported in [zebras](/source/Zebra): five in a [zoo](/source/Zoo) in [California](/source/California)[4] and one in a zoo in [Wisconsin](/source/Wisconsin).[5] Struvite enteroliths are associated with elevated [pH](/source/PH) and mineral concentrations in the [lumen](/source/Lumen_(anatomy)).[6] In [California](/source/California), struvite enteroliths are associated also with a high proportion of [alfalfa](/source/Alfalfa) in the feed and less access to grass pasture. This association has been attributed to the cultivation of alfalfa on [serpentine soils](/source/Serpentine_soil), resulting in high concentrations of [magnesium](/source/Magnesium) in the alfalfa.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

## In humans

In [humans](/source/Human), enteroliths are rare and may be difficult to distinguish from [gall stones](/source/Gall_stone). Their chemical composition is diverse, and rarely can a nidus be found. A [differential diagnosis](/source/Differential_diagnosis) of an enterolith requires the enterolith, a normal gallbladder, and a [diverticulum](/source/Diverticulum).[7][8]

An enterolith typically forms within a [diverticulum](/source/Diverticulum). An enterolith formed in a [Meckel's diverticulum](/source/Meckel's_diverticulum) sometimes is known as a Meckel's enterolith. Improper use of [magnesium oxide](/source/Magnesium_oxide) as a *long-term* [laxative](/source/Laxative) has been reported to cause enteroliths and/or [medication bezoars](/source/Bezoar).[9]

Most enteroliths are not apparent and cause no complications. However, any complications that do occur are likely to be severe. Of these, [bowel obstruction](/source/Bowel_obstruction) is most common,[10] followed by [ileus](/source/Ileus)[11] and [perforation](/source/Gastrointestinal_perforation). Bowel obstruction and ileus typically occur when a large enterolith is expelled from a diverticulum into the [lumen](/source/Lumen_(anatomy)). Perforation typically occurs within the diverticulum.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

On plain X-rays, the visibility of the enterolith depends on its calcium content. Calcium-rich stones usually demonstrate a radiodense rim and a relatively radioluscent core. Choleic acid stones are almost always radiolucent. They sometimes can be visualized on CT scans without contrast; presence of contrast in the lumen may reveal the enterolith as a void. Most often, they are visualized using ultrasound.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

Although recent surveys of enterolith composition are lacking, one early review notes struvite (as in equines), [calcium phosphate](/source/Calcium_phosphate), and [calcium carbonate](/source/Calcium_carbonate) and reports [choleic acid](/source/Choleic_acid).[12] [Deoxycholic acid](/source/Deoxycholic_acid) and [cholic acid](/source/Cholic_acid) have also been reported.[13]

### Treatment

In simple cases of obstruction, where there are no complications, a variety of non-surgical and surgical techniques are used to remove the enterolith.[11] These include crushing the enterolith and milking it back to the stomach or forward to the colon, surgical removal via an uninvolved segment of the gastrointestinal tract, and [resection](/source/Segmental_resection) of the involved segment.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

## See also

- [Acid-base physiology](/source/Acid-base_physiology)

- [Bezoar](/source/Bezoar)

## References

1. ^ [***a***](#cite_ref-Blue1979_1-0) [***b***](#cite_ref-Blue1979_1-1) [***c***](#cite_ref-Blue1979_1-2) Blue MG (April 1979). "Enteroliths in horses--a retrospective study of 30 cases". *Equine Veterinary Journal*. **11** (2): 76–84. [doi](/source/Doi_(identifier)):[10.1111/j.2042-3306.1979.tb01307.x](https://doi.org/10.1111%2Fj.2042-3306.1979.tb01307.x). [PMID](/source/PMID_(identifier)) [477649](https://pubmed.ncbi.nlm.nih.gov/477649).

1. **[^](#cite_ref-pmid7251465_2-0)** Blue MG, Wittkopp RW (July 1981). "Clinical and structural features of equine enteroliths". *Journal of the American Veterinary Medical Association*. **179** (1): 79–82. [PMID](/source/PMID_(identifier)) [7251465](https://pubmed.ncbi.nlm.nih.gov/7251465).

1. **[^](#cite_ref-Lloyd+1987_3-0)** Lloyd K, Hintz HF, Wheat JD, Schryver HF (April 1987). "Enteroliths in horses". *The Cornell Veterinarian*. **77** (2): 172–86. [PMID](/source/PMID_(identifier)) [3552440](https://pubmed.ncbi.nlm.nih.gov/3552440).

1. **[^](#cite_ref-4)** McDuffee LA, Dart AJ, Schiffman P, Parrot JJ (February 1994). "Enterolithiasis in two zebras". *Journal of the American Veterinary Medical Association*. **204** (3): 430–2. [doi](/source/Doi_(identifier)):[10.2460/javma.1994.204.03.430](https://doi.org/10.2460%2Fjavma.1994.204.03.430). [PMID](/source/PMID_(identifier)) [8150704](https://pubmed.ncbi.nlm.nih.gov/8150704).

1. **[^](#cite_ref-5)** Decker RA, Randall TL, Prideauz JW (July 1975). ["Enterolithiasis in a confined Hartman's mountain zebra"](http://www.jwildlifedis.org/cgi/pmidlookup?view=long&pmid=1152174). *Journal of Wildlife Diseases*. **11** (3): 357–9. [doi](/source/Doi_(identifier)):[10.7589/0090-3558-11.3.357](https://doi.org/10.7589%2F0090-3558-11.3.357). [PMID](/source/PMID_(identifier)) [1152174](https://pubmed.ncbi.nlm.nih.gov/1152174). [S2CID](/source/S2CID_(identifier)) [2419057](https://api.semanticscholar.org/CorpusID:2419057).

1. **[^](#cite_ref-6)** Hassel DM, Rakestraw PC, Gardner IA, Spier SJ, Snyder JR (2004). ["Dietary risk factors and colonic pH and mineral concentrations in horses with enterolithiasis"](https://doi.org/10.1111%2Fj.1939-1676.2004.tb02556.x). *Journal of Veterinary Internal Medicine*. **18** (3): 346–9. [doi](/source/Doi_(identifier)):[10.1111/j.1939-1676.2004.tb02556.x](https://doi.org/10.1111%2Fj.1939-1676.2004.tb02556.x). [PMID](/source/PMID_(identifier)) [15188822](https://pubmed.ncbi.nlm.nih.gov/15188822).

1. **[^](#cite_ref-7)** Yang HK, Fondacaro PF (December 1992). "Enterolith ileus: a rare complication of duodenal diverticula". *The American Journal of Gastroenterology*. **87** (12): 1846–8. [PMID](/source/PMID_(identifier)) [1449155](https://pubmed.ncbi.nlm.nih.gov/1449155).

1. **[^](#cite_ref-8)** Chuang JH, Chan HM, Huang YS, Hsieh JS, Huang TJ (August 1993). "Enterolith ileus as a complication of duodenal diverticulosis--one case report and review of the literature". *Gaoxiong Yi Xue Ke Xue Za Zhi*. **9** (8): 488–93. [PMID](/source/PMID_(identifier)) [8230370](https://pubmed.ncbi.nlm.nih.gov/8230370).

1. **[^](#cite_ref-9)** Tatekawa Y, Nakatani K, Ishii H, et al. (1996). "Small bowel obstruction caused by a medication bezoar: report of a case". *Surgery Today*. **26** (1): 68–70. [doi](/source/Doi_(identifier)):[10.1007/BF00311997](https://doi.org/10.1007%2FBF00311997). [PMID](/source/PMID_(identifier)) [8680127](https://pubmed.ncbi.nlm.nih.gov/8680127). [S2CID](/source/S2CID_(identifier)) [24976010](https://api.semanticscholar.org/CorpusID:24976010).

1. **[^](#cite_ref-10)** Gamblin TC, Glenn J, Herring D, McKinney WB (2003). "Bowel obstruction caused by a Meckel's diverticulum enterolith: a case report and review of the literature". *Current Surgery*. **60** (1): 63–4. [doi](/source/Doi_(identifier)):[10.1016/S0149-7944(02)00650-5](https://doi.org/10.1016%2FS0149-7944%2802%2900650-5). [PMID](/source/PMID_(identifier)) [14972313](https://pubmed.ncbi.nlm.nih.gov/14972313).

1. ^ [***a***](#cite_ref-Steenvoorde+2003_11-0) [***b***](#cite_ref-Steenvoorde+2003_11-1) Steenvoorde P, Schaardenburgh P, Viersma JH (2003). "Enterolith ileus as a complication of jejunal diverticulosis: two case reports and a review of the literature". *Digestive Surgery*. **20** (1): 57–60. [doi](/source/Doi_(identifier)):[10.1159/000068852](https://doi.org/10.1159%2F000068852). [PMID](/source/PMID_(identifier)) [12637808](https://pubmed.ncbi.nlm.nih.gov/12637808). [S2CID](/source/S2CID_(identifier)) [20592835](https://api.semanticscholar.org/CorpusID:20592835).

1. **[^](#cite_ref-Raper1921_12-0)** Raper HS (1921). ["A Human Enterolith containing Choleic Acid"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1258956). *The Biochemical Journal*. **15** (1): 49–52. [doi](/source/Doi_(identifier)):[10.1042/bj0150049](https://doi.org/10.1042%2Fbj0150049). [PMC](/source/PMC_(identifier)) [1258956](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1258956). [PMID](/source/PMID_(identifier)) [16742974](https://pubmed.ncbi.nlm.nih.gov/16742974).

1. **[^](#cite_ref-13)** Fantl P, Rollo AJ, Strosberg H (August 1965). ["Chemical analysis of an enterolith"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1552302). *Gut*. **6** (4): 384–6. [doi](/source/Doi_(identifier)):[10.1136/gut.6.4.384](https://doi.org/10.1136%2Fgut.6.4.384). [PMC](/source/PMC_(identifier)) [1552302](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1552302). [PMID](/source/PMID_(identifier)) [4953381](https://pubmed.ncbi.nlm.nih.gov/4953381).

## External links

Classification D ICD-10: K56.4 ICD-9-CM: 560.39 SNOMED CT: 40515007

Look up ***[enterolith](https://en.wiktionary.org/wiki/enterolith)*** or ***[nidus](https://en.wiktionary.org/wiki/nidus)*** in Wiktionary, the free dictionary.

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Adapted from the Wikipedia article [Enterolith](https://en.wikipedia.org/wiki/Enterolith) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Enterolith?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.