From the Guidelines
Evans syndrome is diagnosed when a patient has both autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP) occurring either simultaneously or sequentially, with no underlying cause identified, as evidenced by a positive direct antiglobulin test and decreased platelet count. The diagnosis criteria for Evans syndrome include:
- A positive direct antiglobulin test (Coombs test) for AIHA, as mentioned in the context of ruling out concurrent Evans’ syndrome 1
- Decreased hemoglobin levels
- Elevated reticulocyte count
- Increased lactate dehydrogenase
- Decreased haptoglobin
- A platelet count below 100,000/μL with normal bone marrow examination showing adequate megakaryocytes for ITP Additional testing is necessary to rule out secondary causes such as systemic lupus erythematosus, common variable immunodeficiency, lymphoproliferative disorders, or other autoimmune conditions, and may include history and physical examination, CBC, peripheral blood smear, and reticulocyte count, as well as bone marrow evaluation if other cell lines are affected and there is concern for aplastic anemia 1. Some patients may also develop autoimmune neutropenia as part of the syndrome. Diagnosis often requires collaboration between hematologists and immunologists, as Evans syndrome represents an immune dysregulation where antibodies target multiple blood cell lines, and patients with newly diagnosed ITP should undergo testing for HIV, HCV, HBV, and H. pylori, as well as nutritional evaluation 1.
From the Research
Diagnosis Criteria for Evans Syndrome
The diagnosis of Evans syndrome is based on the presence of two or more immune cytopenias, typically autoimmune hemolytic anemia (AIHA) and immune-mediated thrombocytopenia 2, 3, 4, 5. The diagnosis requires a combination of clinical and laboratory findings, including:
- Autoimmune hemolytic anemia (AIHA) characterized by hemolysis, elevated lactate dehydrogenase, low haptoglobin, and elevated bilirubin levels 4
- Immune-mediated thrombocytopenia characterized by a low platelet count and presence of platelet antibodies 4
- Exclusion of other diseases causing anemia and thrombocytopenia, such as lymphoproliferative disorders or immune neutropenia 3, 5
Laboratory Tests
Laboratory tests used to diagnose Evans syndrome include:
- Blood samples to evaluate hemoglobin, platelet count, and reticulocyte count 3, 4
- Coombs examination to detect autoantibodies against red blood cells 3
- Virologic tests to exclude underlying infections 3
- Bone marrow examination to evaluate bone marrow function and exclude other hematological disorders 3, 6
- Direct antiglobulin test to detect immunoglobulin G (IgG) or complement on red blood cells 4
Clinical Presentation
The clinical presentation of Evans syndrome can vary, but common features include: