autoimmune hemolytic anemia

Question 1

define

Answer 1

Autoimmune haemolytic anaemia (AIHA) may be divided in to ‘warm’ and ‘cold’ types, according to at what temperature the antibodies best cause haemolysis.

It is most commonly idiopathic but may be secondary to a lymphoproliferative disorder, infection or drugs.

AIHA is characterised by a positive direct antiglobulin test (Coombs’ test)

Question 2

warm AIHA- where does hemolysis tend to happen

Answer 2

Warm AIHA

In warm AIHA the antibody (usually IgG) causes haemolysis best at body temperature and haemolysis tends to occur in extravascular sites, for example the spleen.

Question 3

causes of warm AIHA

Answer 3

Causes of warm AIHA

• autoimmune disease: e.g. systemic lupus erythematosus*
• neoplasia: e.g. lymphoma, CLL
• drugs: e.g. methyldopa

Question 4

warm AIHA- mx

Answer 4

Management options include

• steroids,
• immunosuppression and
• splenectomy

Question 5

cold AIHA- define

Answer 5

Cold AIHA

The antibody in cold AIHA is usually IgM and causes haemolysis best at 4 deg C. Haemolysis is mediated by complement and is more commonly intravascular.

Question 6

cold AIHA- s/s

Answer 6

Features may include symptoms of Raynaud’s and acrocynaosis.
Causes of cold AIHA

neoplasia: e.g. lymphoma
infections: e.g. mycoplasma, EBV

Question 7

cold AIHA- mx

Answer 7

Patients respond less well to steroids