Bovis ISSN 2398-2993

Aortic rupture

Synonym(s): Aneurysm

Contributor(s): Louise Cox-O’Shea, Ben Strugnell , Gayle Hallowell

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Introduction

  • Very rare cause of sudden death in cattle.
  • Certain etiologies are limited to specific geographical areas (see below).
  • Rupture of the aortic root may occur during strenuous exercise and usually causes sudden death.
  • Cause: etiology uncertain; may be associated with aneurysm, and where present, onchocerciasis. Can be caused by Marfan syndrome in calves.
  • Signs: sudden death on exertion; peracute heart failure, sudden severe ventricular dysrhythmia.
  • Diagnosis: post mortem examination.
  • Treatment: none.
  • Prognosis: hopeless for true vessel rupture.

Pathogenesis

Etiology

  • Obscure, but Onchocerca armillata Onchocerca spp may be involved, however many carcasses inspected in the abattoir showed heavy infections but limited cardiovascular changes.
  • Marfan syndrome Marfan syndrome results in reduced elasticity in various structures, it can lead to aortic aneurysm and rupture.
    • It is caused by a mutation in the fibrillin- 1 gene.
    • It is an autosomal dominant genetic disorder.
    • The majority of cases seen in adult cattle probably do not have Marfan syndrome, although some of the histological features of idiopathic aortic aneurism are similar, ie there may be an underlying connective tissue defect.
  • Often idiopathic.

Pathophysiology

  • An aneurysm may result from progressive degenerative changes to connective tissue. 
  • Inflammation is not usually a feature.
  • It is likely that this degenerative change occurs slowly, over a prolonged time period, as there is often smooth muscle hypertrophy and granulation tissue at the site of the aneurysm, in cases of spontaneous rupture.
    • Increased arterial pressure during activity is a likely precursor to arterial rupture.
  • Histological changes suggest progressive weakening with attempts at repair, before final rupture and exsanguination.
  • The cause of the progressive weakening is often not evident.
  • Nodules/atheromatous plaques caused by Onchocerca armillata Onchocerca spp may lead to vessel wall damage, resulting in aneurysm and subsequent rupture.
  •  Lack of elastin in the aortic wall (due to Marfan syndrome) may also predispose to aneurysm and subsequent rupture.

Timecourse

  • Sudden death or peracute heart failure with death delayed for some hours.
  • Very occasionally, animal may survive with minimal clinical signs when rupture occurs through interventricular septum and defect is restrictive.

Epidemiology

  • This is usually a sporadic condition, most commonly presenting as the sudden death of a single animal. However there are (intriguing) reports that the condition may occur in clusters, with 2-4 animals dying suddenly within a few days. There is no satisfactory explanation for this phenomenon at present.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Begam R, Islam S, Saikia M, Kalita A, Bulbul K H, Bam J O & Pathak P (2015) Prevalence of Aortic Onchocerciasis in cattle of Assam. Veterinary Practitioner 16 (2).
  • Boerma S, Back W & Sloet van Oldruitenborgh-Oosterbaan M M (2012) The Friesian horse breed: A clinical challenge to the equine veterinarian? Equine Vet Educ 24 (2), 66-71.
  • Hirano T, Matsuhashi T, Kobayashi N, Watanabe T & Sugimoto T (2012) Identification of an FBN1 mutation in bovine Marfan syndrome - like disease. Anim Genet 43(1), 11-7 PubMed.
  • Crawshaw T, Wessels M, Howie F, McElroy M et al (2011) Idiopathic arterial aneurysm/ rupture causing sudden death in dairy cattle. Veterinary Record 169 (10), pp 261 PubMed.
  • Lamm C G, Guard C L, Erb H N & Njaa B L (2007) Characterisation of rupture of abdominal artery aneurysm in dairy cattle. Journal of Veterinary Diagnostic Investigation 19, pp 273-278.
  • Potter K A & Besser T E (1994) Cardiovascular lesions in Bovine Marfan Syndrome. Veterinary Pathology 31, 501-509 PubMed.
  • Potter K A, Hoffman Y, Sakai L Y, Byers P H et al (1993) Abnormal Fibrillin Metabolism in Bovine Marfan Syndrome. American Journal of Pathology 142 (3), pp 803-810 PubMed.
  • Kiryu K et al (1987) Cardiopathology of sudden cardiac death in the race horse. Heart Vessels Suppl 2, 40-46 PubMed.
  • van der Linde-Sipman J S et al (1985) Necrosis and rupture of the aorta and pulmonary trunk in four horses. Vet Pathol 22 (1), 51-53PubMed.
  • Rooney J R et al (1979) Rupture of the aorta. Mod Vet Pract 60 (5), 391-392PubMed.

Other sources of information

  • Urquhart G M, Armour J, Duncan J L, Dunn A M & Jennings F W (1996) Veterinary Parasitology.


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