Autoimmune hemolytic anemia: Difference between revisions
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*Can be primary (idopathic) or due to another disease process (e.g. malignancy, autoimmune disease, infection) | *Can be primary (idopathic) or due to another disease process (e.g. malignancy, autoimmune disease, infection) | ||
=="Warm" Autoimmune Hemolytic Anemia== | ==="Warm" Autoimmune Hemolytic Anemia=== | ||
''Autoantibodies agglutinate to RBCs at higher temperatures'' | ''Autoantibodies agglutinate to RBCs at higher temperatures'' | ||
*IgG mediated, usually pan-reactive to patient's and transfused RBCs | *IgG mediated, usually pan-reactive to patient's and transfused RBCs | ||
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**Medications: methyldopa, quinidine, [[penicillin]] | **Medications: methyldopa, quinidine, [[penicillin]] | ||
=="Cold" Autoimmune Hemolytic Anemia== | ==="Cold" Autoimmune Hemolytic Anemia=== | ||
''Autoantibodies agglutinate at lower temperatures'' | ''Autoantibodies agglutinate at lower temperatures'' | ||
*IgM mediated | *IgM mediated | ||
Revision as of 11:23, 8 September 2016
Background
- Autoimmune hemolytic anemia (AIHA) = generation of auto-antibodies towards red blood cell membrane antigens, leady to hemolysis.
- Can be primary (idopathic) or due to another disease process (e.g. malignancy, autoimmune disease, infection)
"Warm" Autoimmune Hemolytic Anemia
Autoantibodies agglutinate to RBCs at higher temperatures
- IgG mediated, usually pan-reactive to patient's and transfused RBCs
- Extravascular (i.e. in spleen) hemolysis--> unconjugated > conjugated hyperbilirubinemia
- Haptoglobin low, LDH may be normal
- Causes:
- Lymphoma, especially Non-Hodgkin's lymphoma
- Leukemia, particularly chronic lymphocytic leukemia
- Collagen vascular diseases (E.g. Systemic Lupus Erythematosus, Rheumatoid arthritis, Giant cell arteritis
- Viral-induced or HIV-associated
- Medications: methyldopa, quinidine, penicillin
"Cold" Autoimmune Hemolytic Anemia
Autoantibodies agglutinate at lower temperatures
- IgM mediated
- Intravascular hemolysis--> high LDH, low haptoglobin, hemoglobinuria
- Causes:
- Infection, most commonly Mycoplasma pneumoniae and mononucleosis, also varicella, listeria, influenza
- Multiple myeloma and other plasmacytomas
- Idiopathic
Clinical Features
- Signs and symptoms of anemia (fatigue, pallor, palpitations, etc.)
- Jaundice and scleral icterus
- Signs/symptoms of underlying disease process
- Cold-type:
- Acrocyanosis, Raynaud's, vascular occlusion with peripehral tissue ischemia
Differential Diagnosis
Evaluation
- CBC, LFTs, LDH, haptoglobin
- Direct Coombs test - blood sample is removed of plasma and incubated with anti-human immunoglobulin (aka "Coombs reagent"). This detects if autoantibodies are attached to RBCs or compliment. If the RBCs are coated with IgG (positive direct Coombs test), this suggests the diagnosis of "warm AIHA. If the RBCs are coated with only compliment, this suggests the diagnosis of "cold" AIHA
Treatment
Warm AIHA
- Oral prednisone 1-1.5mg/kg/day for 1-3 weeks with taper after hemoglobin stable
- may need several months of low dose prednisone to remain in remission
- Splenectomy and/or cytotoxic drugs for for steroid-refractory disease
- Plasmapharesis as temporizing measure for severe disease
- Transfuse only if truly life-threatening anemia, least incompatible units possible
Cold AIHA
- No treatment for mild disease
- Immunosuppressive or cytotoxic medications can be considered
- Plasmapharesis for severe disease