Felis ISSN 2398-2950

Anaphylaxis

Synonym(s): Anaphylactic shock, angiedema

Contributor(s): Kyle Braund

Introduction

  • Cause: systemic Type I hypersensitivity response.
  • Signs: facial urticaria and pruritus, vomiting, shock.
  • Diagnosis: history and clinical signs.
  • Treatment: intravenous fluids, corticosteroids, antihistamine.
  • Prognosis: good if responds to immediate emergency treatment.

Pathogenesis

Etiology

Specific

  • Previous exposure to allergen.

Pathophysiology

  • Mast cell degranulation   →   release of chemical mediators   →   clinical signs.
  • Animal must first be sensitized to antigen to produce anaphylactic reaction.
  • Production of IgE occurs initially which binds to tissue mast cells and circulating blood basophils which renders these cells 'sensitized'.
  • On second exposure antigen binds to IgE on mast cells and basophils   →   degranulation and vasoactive amine release and pro-inflammatory mediator release.
  • Multiple effects on many body systems   →   signs of shock ( mainly as a consequence of hypovolemia from increased vascular permeability and pooling of blood from vasodilation).

Timecourse

  • Acute (within minutes of exposure in sensitized animal).

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.
  • Mueller D L & Noxon J O (1990) Anaphylaxis: pathophysiology and treatment. Comp Cont Ed Pract Vet 12 (2), 157-170 VetMedResource.

Other sources of information

  • Cohen R D (1995) Systemic anaphylaxis. In: Kirk's Current Veterinary Therapy XII. J D Bonagura (ed). Philadelphia: W B Saunders. pp 150-152.


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