Equis ISSN 2398-2977

Abdomen: hemoperitoneum

Synonym(s): Intra-abdominal hemorrhage

Contributor(s): Rachael Conwell, Janice Sojka, Han van der Kolk


  • Hemoperitoneum, or abdominal hemorrhage, is defined as blood accumulation within the peritoneal cavity. 
  • It is an uncommon occurrence, and can be difficult to diagnose as the clinical signs are often non-specific and may mimic other diseases.  
  • Diagnostic and therapeutic decisions must be made rapidly, however, to prevent fatal ex-sanguination. 
  • Cause: multifactoral.
  • Signs: colic or abdominal discomfort, pale mucous membranes, tachypnea, tachycardia, depression.
  • Diagnosis: rectal examination, nasogastric intubation, peritoneal tap, blood biochemistry and hematology, platelet count, clotting times, ultrasonography, exploratory laparotomy.
  • Treatment: fluid therapy, blood transfusion, NSAIDs, antibiotics, corticosteroids, exploratory laparotomy and surgical repair.
  • Prognosis: good to poor depending on severity of blood loss and underlying cause.



  • Multifactorial.

Predisposing factors

  • Most broadly, hemoperitoneum results from free red blood cells in the peritoneal space.
  • Blood enters the abdominal cavity either through ruptured blood vessels or organs, or secondary to a coagulopathy.
  • If the amount of free blood is small there may be no associated clinical signs. 
  • The amount of blood in the peritoneal space becomes a concern when a sufficient volume of blood is lost at a rate fast enough to compromise delivery of oxygen to the tissues.


  • Common causes of hemoperitoneum vary between studies. Most commonly identified causes in the UK include rupture of specific blood vessels, periparturient hemorrhage, splenic lesion and idiopathic.
  • Neoplasia, idiopathic and trauma, most often blunt force from being kicked by another horse, were the most commonly identified predisposing factors in another study from the US.
  • Neoplasia, such as hemangiosarcoma, ruptured pheochromocytoma   Pheochromocytoma  .
  • Other described causes include uterine or vaginal perforation   Vagina: trauma  , coagulopathy including DIC   Disseminated intravascular coagulation  , organ rupture, ovarian hemorrhage due to normal ovarian activity or neoplasia, and post-operative complications.


  • Blunt trauma: concussive force produced by a sudden blow to the abdomen can cause the spleen to rupture or tear resulting in hematoma   Hematoma  formation and hemorrhage into the peritoneal cavity. Similarly, such force may also cause avulsion of mesenteric blood vessels or the vessels supplying the spleen, liver, kidneys, or reproductive organs.
  • Organ or tumor rupture: friable tissues in either a neoplasm or damaged organ (such as the liver in cases of hyperlipemia   Hyperlipemia syndrome  ) may   →   loss of blood vessel integrity and subsequent bleeding into the peritoneal cavity.
  • Reproductive trauma: tearing and rupture of the anterior vagina   Vagina: trauma  during natural service breeding may cause rupture of the blood vessels in the vaginal wall resulting in hemoabdomen. Prolonged dystocia   Reproduction: dystocia  may result in perforation of the uterus, resulting in the release of uterine contents and blood into the abdomen.
  • Hemorrhage from uterine arteries and, less frequently, iliac arteries is usually detected immediately post-partum (within 48 h post-foaling). Thought to result from age-related degeneration of the blood vessel walls, resulting in aneurysm formation and subsequent rupture due to either the weight of the late term foal or increased pressure during uterine contractions.
  • Mesenteric artery rupture resulting from a defect in blood vessel wall and subsequent aneurysm formation. Potential role ofStrongylus vulgarisin cranial mesenteric arteries.
  • Abdominal hemorrhage may also occur secondary to either primary or acquired coagulopathy.


  • Variable - can vary between hours to weeks depending on the underlying cause. 
  • The more rapid the loss of blood into the abdomen, the more severe the clinical signs and the more rapid the horse's deterioration.


  • In a retrospective review, age was ~12 years, with older animal over represented compared to hospital averages. 
  • More common in Arabians   Arab  and Thoroughbreds   Thoroughbred  .


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Fouche N et al (2014) Noncitrated blood transfusions used tas adjunctive treatment in a 7-year-old Shetland pony with haemoperineum due to a ruptured corpus haemorragicum. Equine Vet Educ 26 (5), 250-254 VetMedResource.
  • Holmes J M, Nath L C & Nuurlink M A (2013) Laparoscopic cauterisation of the testicular arteries to manage hemoperitoneum in a gelding. Equine Vet Educ 25 (6), 297-300 VetMedResource.
  • Compostella F, Roberts V L H & Tremaine W H (2012) Haemoabdomen and colitis following a colon displacement in a 9-year-old Thoroughbred mare. Equine Vet Educ 24 (11), 563-568 VetMedResource.
  • Finding E J T, Eliashar E, Johns I C & Dunkel B (2011) Autologous blood transfusion following an allogenic transfusion reaction in a case of acute anaemia due to intra-abdominal bleeding. Equine Vet Educ 23 (7), 339-342 VetMedResource.
  • Conwell R C et al (2010) Haemoperitoneum in horses: a retrospective review of 54 cases. Vet Rec 167 (14), 514-518 PubMed
  • Arnold C E, Payne M, Thompson J A, Slovis N M & Bain F T (2008) Periparturient haemorrhage in mares: 73 cases (1998-2005). JAVMA 232 (9), 1345-1351 PubMed.
  • Dechant J E, Nieto J E & MeJeune S S (2006) Hemoperitoneum in horses: 67 cases (1989-2004). JAVMA 229 (2), 253-258 PubMed.
  • Pusteria N, Fecteau M E, Madigan J E, Wilson W D & Magdesian K G (2005) Acute hemoperitoneum in horses: a review of 19 cases (1992-2003). J Vet Intern Med 19 (3), 344-347 PubMed.