ISSN 2398-2977      

Gastrointestinal: enterolith



  • Enteroliths are masses that build up in the intestinal system, particularly the right dorsal colon.
  • Cause: usually form as concretions around foreign bodies or food material.
  • Signs: include colic, although they may be non-pathogenic, they can cause partial obstructions, particularly at the entrance to the transverse colon, and within the small colon if they move.
  • Diagnosis: rectal palpation, radiography or at laparotomy.
  • Treatment: surgical removal.
  • Prognosis: good, provided prompt treatment is carried out when necessary.



  • Enteroliths are mineral concretions within the guts.
  • They usually have a foreign body nidus such as a nail/piece of wire.
  • They are slow growing, but can reach large sizes.

Predisposing factors

  • Intestinal foreign bodies.
  • Diets high in magnesium, nitrogen and phosphorus.


  • Masses develop in the intestines, particularly the right dorsal colon.
  • They rarely cause problems there, though they may cause intermittant, low-grade chronic colic due to progressive partial obstruction of the gut lumen.
  • They may move into the entrance to the transverse colon and cause colic due to partial obstruction in this situation.
  • They may move into the narrower small colon and cause complete obstruction.
  • Complete obstruction results in the development of signs of severe colic that requires surgery.
  • Partial intermittent obstruction of the colonic lumen results in blockage of the intestinal transit. Mild pain can result due to stretching of the bowel.
  • In cases involving complete obstruction of the colonic lumen, the pathologic mechanisms are as follows:
    • Stasis of intestinal fluid proximal to the obstruction results in the multiplication of intestinal bacteria and the release of gas.
    • Increased pressure within the bowel due to fluid and gas build up causes distension, which results in an increase in pain, as well as a decrease in peristalsis.
    • The result is progressive filling and swelling of the gut, and atonia of the gut wall.
    • The enterolith can get tightly wedged in the small colon. The bowel spasms around the foreign body and pressure necrosis occurs. This can lead to rupture (ie the necrotic small colon is the site and cause of gut rupture with enteroliths, not degeneration of the proximal distended bowel).
    • Endotoxins and bacteria leak into the bloodstream and peritoneal cavity, causing damage to epithelial cells and platelets.
    • Platelets release thromboxane and serotonin causing vasoconstriction.
    • Endothelial cell damage causes the stimulation of neutrophils.
    • Endotoxemia   Endotoxemia: overview  may result, and this can cause further sensitization of the pain receptors.
    • Electrolyte and fluid sequestration contribute to the development of circulatory collapse.
    • Hypovolemia, endotoxic shock, electrolyte and acid/base abnormalities develop.
    • Pain due to the stretching of proximal bowel wall, as well as to gut and vascular compromise at the site of the lesion is generally continuous, and shows no, or only temporary response to analgesics.
    • Cardiovascular compromise is reflected by tachycardia, a decrease in pulse quality, mucous membrane congestion or cyanosis, and an increase in capillary refill time. Secondary increases in packed cell volume (PCV) and plasma proteins (TPP)are seen, and metabolic acidosis causes tachypnoea.
  • In cases that involve colonic, rather than small intestinal, obstruction, the development of clinical signs is gradual, and the resulting pain is usually mild, until severe bowel wall compromise is present.


  • Even when complete bowel obstruction occurs, it may take several hours for severe signs to develop.


This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login


This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login


This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Barrett E J & Munsterman A S (2013) Parainguinal laparotomy as an alternative surgical approach for removal of an enterolith in the small colon of a horse. Equine Vet Educ 25 (9), 442-446 VetMedResource.
  • Hassel D M et al (1999) Evaluation of enterolithiasis in equids - 900 cases (1973-1996). JAVMA 214 (2), 233-237 PubMed.
  • Cummings C A, Copedge K E & Confer A W (1997) Equine gastric impaction, ulceration and perforation due to persimmon (Diopyros virginiana) ingestion. J Vet Disgn Invest (3), 311-313 PubMed.
  • Peloso J G et al (1992) Obstructive enterolith in an 11-month-old miniature horse. JAVMA 201 (11), 1745-1746 PubMed.
  • Lloyd K et al (1987) Enteroliths in horses. Cornell Vet 77 (2), 172-186 PubMed.
  • Blue M G et al (1981) Clinical and structural features of equine enteroliths. JAVMA 179 (1), 79-82 PubMed.
  • Blue M G et al (1979) Enteroliths in horses - a retrospective study of 30 cases. Equine Vet J 11 (2), 76-84 PubMed.
  • Blue M G (1979) Colonic obstructions due to enteroliths in four horses. Vet Rec 104 (10), 209-211 PubMed.

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!


To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code