Introduction

• Rare.
• Cause: primary or secondary to drugs, eg penicillin (hapten phenomenon)    Penicillin G  , neoplasia      Gastrointestinal: neoplasia - melanoma  , viral or bacterial infections.
• Signs: depend on underlying disease; non-specific malaise, pale mucous membranes, tachycardia.
• Diagnosis: Coomb's test, bone marrow biopsy.
• Treatment: blood transfusion   Blood: transfusion  , corticosteroids   Dexamethasone  , plasma phoresis.
• Prognosis: depends on cause.

Pathogenesis

Predisposing factors

• Recent drug administration (paten phenomenon).
• Recent systemic bacterial or viral infection.
• Equine infectious anemia   Equine infectious anemia (EIA)  .
• Clostridum perfringens  Clostridia spp  infections   Gastrointestinal: clostridiosis  have been reported in association with AIHA in at least two cases.
• Neoplastic conditions, especially lymphosarcoma    /mesothelioma.

Pathophysiology

• Aberrant production of antibodies that bind surface antigens of red blood cells.
• Antibody production is thought to occur in one of three ways:
  • The erythrocyte membrane is altered by systemic bacterial or viral infections or neoplastic disorders and antibody production is directed at this antigen perceived as 'foreign'.
  • Immunocompetent clones develop and direct their products at the red cell membrane.
  • Small molecules like pharmaceuticals bind to membrane associated antigens creating a hapten-facilitated immune reaction.

Diagnosis

Treatment

Outcomes