ISSN 2398-2977      

Anemia: overview

pequis
Contributor(s):

Introduction

  • The life-span of equine erythrocytes is about 100 days.
  • Anemia is defined as a deficiency of erythrocytes either in number or volume or both.
  • Cause:
    • Hemorrhage: internal vs external, acute vs chronic.
    • Hemolysis: intravascular vs extravascular, immune-mediated (primary or secondary), direct toxic damage, oxidative damage, infectious disease.
    • Increased use/shortened half-life of RBCs.
    • Decreased production.
  • Signs: depends on the degree of chronicity of the anemia. Common features include pallor or jaundice, lethargy, weakness, collapse, poor performance/exercise intolerance.
  • Diagnosis: hematological evaluation, including a blood smear, is essential for the identification of anemia.
  • Treatment: depends on the cause of the anemia.
  • Prognosis: depends on the cause of the anemia.

Pathogenesis

Etiology

  • Hemorrhage: external or internal blood loss.
  • Hemolysis: destruction of red blood cells:
    • Immune-mediated (primary or secondary).
    • Toxic: direct, eg following DMSO administration, or oxidative damage, eg red maple leaf or onion ingestion.
    • Infectious disease, eg equine infectious anemia, babesiosis, ehrlichia.
  • Anemia of chronic disease: increased use and shortened red blood cell lifespan.
  • Failure of production: myelophthisic disease, eg bone marrow neoplasia, renal disease resulting in reduced production of erythropoietin.

Predisposing factors

General

Pathophysiology

  • Anemia can be induced via several mechanisms.
  • Hemorrhage: external or internal blood loss.
  • Hemolysis: destruction of red blood cells:
    • Immune-mediated (primary or secondary).
    • Toxic: direct, eg following DMSO adminitration, or oxidative, eg red maple leaf or onion ingestion.
    • Infectious disease, eg equine infectious anemia   Equine infectious anemia (EIA)  , babesiosis   Babesiosis  , ehrlichiosis   Potomac Horse Fever 
  • Anemia of chronic disease: increased use and shortened red blood cell lifespan.
  • Failure of production: myelophthisic disease, eg bone marrow neoplasia, renal disease resulting in reduced production of erythropoietin.
  • Some diseases induce anemia by more than one mechanism, eg EIA, causes both hemolysis and reduced red cell production.
  • Lymphosarcoma might induce anemia both via myelophthisis and via immune-mediated mechanisms.

Timecourse

  • Anemia in case of equine infectious anemia   Equine infectious anemia (EIA)  is progressive and cyclic.
  • Anemia following (severe) blood loss   Anemia: blood loss  /trauma is seen suddenly - not always external bleeding.
  • Rapid onset anemia:
  • Slow onset anemia:
    • Bone marrow suppression.
    • Parasitism.

Diagnosis

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

Treatment

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

Prevention

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

Outcomes

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

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Hollis A R & Corley K T T (2011) Initial experience of ultrapurified bovine haemoglobin use in horses. Equine Vet Educ 23 (11), 562-568 VetMedResource.
  • Hart K A (2008) Evaluation and management of anaemia in the post operative colic patient. Equine Vet Educ 20 (8), 427-432 VetMedResource.
  • Piercy R J, Swardson C J & Hinchcliff K W (1998) Erythroid hypoplasia and anemia following administration of recombinant human erythropoietin to two horses. JAVMA 212, 244-247 PubMed.
  • McConnico R S, Roberts M C & Tompkins M (1992) Penicillin-induced immune-mediated hemolytic anemia in a horse. JAVMA 201, 1402-1403 PubMed.
  • Mair TS, Taylor F G & Hillyer M H (1990) Autoimmune haemolytic anaemia in eight horses. Vet Rec 126, 51-53 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!