warm autoimmune hemolytic anemia
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Etiology
- idiopathic
- secondary (50%)
- lymphoproliferative disease
- connective tissue disease
- immunodeficiency
- ulcerative colitis
- pharmaceutical agents
- alpha-methyldopa (antibody to Rh antigen)
- penicillin type (stable hapten)
- cephalosporins[5]
- quinidine type (unstable hapten)
- post viral infection
- non-lymphoproliferative neoplasms (rare)
Epidemiology
- 70% of patients with autoimmune hemolytic anemia
- median age of onset is 52 years
- may occur at any age
- slight female predominance
Pathology
- IgG autoantibody binds to Rh antigen or Rh-like antigen
- IgG antibodies bind complement (C3d) but more often facilitate Fc receptor mediated erythrocyte destruction by splenic macrophages
Clinical manifestations
- rapid or insidious onset
- anemia
- dyspnea
- fatigue
- jaundice
- splenomegaly
- durable remission after initial therapy in 30%
- chronic relapsing course nore common
Laboratory
- complete blood count: anemia
- reticulocyte count: reticulocytosis
- peripheral blood smear:
- direct antiglobulin test (Coomb's test):
- erythrocyte antibody is IgG
- complement C3d in erythrocytes is negative or only weakly positive
- optimal temperature for erythrocyte antibody binding is 37 C
- IgG autoantibodies react with all reagent red cells from blood bank (panagglutinins), even when associated chronic lymphocytic leukemia[5]
- serum chemistries
- serum bilirublin: bilirubinemia
- serum haptoglobin is low or absent
- serum LDH is increased[1]
* schistocytes on peripheral blood smear sufficient to rule out warm autoimmune hemolytic anemia without direct antiglobulin testing (DAT)[1]
Complications
Management
- withdrawal of offending agent(s)
- hemolysis general resolves with withdrawal of offending drug
- hemolysis may be prolonged after withdrawal of some offending drugs (i.e. fludarabine)[1]
- glucocorticoid: prednisone 1-1.5 mg/kg/day
- most patients respond to therapy within 2-3 weeks
- hematocrit may normalize or stabilize in 30-90 days
- > 10-15 mg/day required to maintain acceptable blood hemoglobin
- immunosuppressive agents if unresponsive to low-dose corticosteroids
- other agents for which anecdotal evidence exists
- danazol
- high-dose intravenous immune globulin
- splenectomy if inadequate response to prednisone or immunosuppressants
- 50-70% of patients show marked improvement
- later relapse may occur
- severely anemic patients may receive ABO & Rh type-specific blood transfusion even though all units may be incompatible (temporary benefit even with incompatible units)
More general terms
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015, 2018, 2022.
- ↑ Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 666
- ↑ Packman CH. Hemolytic anemia due to warm autoantibodies. Blood Rev. 2008 Jan;22(1):17-31 PMID: https://www.ncbi.nlm.nih.gov/pubmed/17904259
- ↑ Crowther M, Chan YL, Garbett IK, Lim W, Vickers MA, Crowther MA Evidence-based focused review of the treatment of idiopathic warm immune hemolytic anemia in adults. Blood. 2011 Oct 13;118(15):4036-40. PMID: https://www.ncbi.nlm.nih.gov/pubmed/21778343
- ↑ 5.0 5.1 5.2 5.3 5.4 Rothaus C NEJM Resident 360. Aug 14, 2019 https://resident360.nejm.org/clinical-pearls/autoimmune-hemolytic-anemia
- ↑ Sudulagunta SR, Kumbhat M, Sodalagunta MB et al. Warm autoimmune hemolytic anemia: clinical profile and management. J Hematol. 2017;6(1):12-20 PMID: https://www.ncbi.nlm.nih.gov/pubmed/32300386 PMCID: PMC7155818 Free PMC article https://www.thejh.org/index.php/JH/article/view/303