Anaemia - Haemolytic Anaemia - Autoimmune Haemolytic Anaemia (AIHA) Flashcards
What is AIHA?
Autoimmune Haemolytic Anaemia - antibodies are created against the patient’s RBCs, leading to their destruction.
What are the types of AIHA? (2).
Based on the temperature of the functioning of autoantibodies :-
- Warm-Type AIHA (commoner).
- Cold-Type AIHA.
What is Warm-Type AIHA?
Extravascular (splenic) haemolysis occurs at normal or above normal temperatures by IgG antibodies.
Aetiology of Warm-Type AIHA.
- Idiopathic usually.
- Autoimmune Disease e.g. SLE.
- Neoplasia e.g. Lymphoma, CLL.
- Drugs e.g. Methyldopa.
What is Cold-Type AIHA?
Cold-Agglutinin Disease - agglutination (and consequent destruction) at lower temperatures; intravascular haemolysis mediated by Complement and IgM.
Aetiology of Cold-Type AIHA (4).
Secondary to Other Conditions e.g. :
- Lymphoma.
- Leukaemia.
- SLE.
- Infections e.g. Mycoplasma, EBV, CMV, HIV.
Clinical Presentation of Cold-Type AIHA (2).
- Raynaud’s.
2. Acrocyanosis.
Investigations of AIHA (3).
- Bloods : Anaemia, Reticulocytosis, Low Haptoglobin, Raised LDH and Indirect Bilirubin.
- Blood Film : Spherocytes and Reticulocytes.
- Positive Coombs’ (Direct Antiglobulin) Test.
What is Coombs Test?
Antibodies are used against the autoantibodies to test for their presence.
Management of AIHA.
- Blood Transfusions.
- Prednisolone (Steroids).
- Rituximab (Monoclonal Antibody against B cells).
- Splenectomy.