Autoimmune hemolytic anemia (AIHA)

Autoimmune hemolytic anemia (AIHA)

Types:-

1. Warm AIHA (Most common subtype of AIHA):- IgG antibodies against RBCs; “Warm” because agglutination of RBCs occurs at warmer temperatures; Examples are idiopathic, autoimmune disorders (e.g. SLE, RA), CLL, Drugs (e.g. Beta-lactams, alpha-methyldopa).
Warm AIHA is characterized by the triad of anemia, jaundice and hepatosplenomegaly.

Diagnosis:-
1. CBC shows Low hemoglobin, Low hematocrit, and High reticulocytes.
2. Features of hemolysis present (e.g. High LDH, High UCB, and Low haptoglobin).
3. PBS shows spherocytes.
4. Direct coombs' test is positive.

Management:-
1. Incompatible blood transfusions (i.e. transfusion of incompatible blood)
2. Steroids (e.g. prednisone)
3. Rituximab (Anti-CD20 antibody).
4. Immunosuppressive agents (e.g. mycophenolate mofetil, azathioprine, cyclophosphamide).
5. Splenectomy.
6. Hematopoietic stem cell transplantation (HSCT).
7. Treat the underlying etiologies. 

Complications:- DVT, Pulmonary embolism

2. Cold AIHA (Least common subtype of AIHA):- IgM antibodies against RBCs; “Cold” because agglutination of RBCs occurs at cooler temperatures; Examples are Mycoplasma pneumonia, infectious mononucleosis and lymphoproliferative diseases.

Diagnosis:-
1. CBC shows Low hemoglobin, Low hematocrit, and High reticulocytes.
2. Features of hemolysis present (e.g. High LDH, High UCB, and Low haptoglobin).
3. PBS shows spherocytes.
4. Direct coombs' test is positive.

Management:-
1. Avoid exposure to cold and keep the patient warm (e.g. warm blankets).
2. Rituximab (Anti-CD20 antibody).
3. Chemotherapy agents (e.g. fludarabine, bendamustine)
4. Steroids and splenectomy are not recommended. 
5. Treat the underlying etiologies. 

Complications:- Raynaud phenomenon.