From the Guidelines
Evan syndrome is diagnosed when a patient has both immune thrombocytopenia (ITP) and autoimmune hemolytic anemia (AIHA) occurring simultaneously or sequentially, requiring laboratory evidence of both conditions and a thorough investigation to rule out other causes of combined cytopenias. The diagnosis of Evan syndrome is based on the presence of low platelet count (thrombocytopenia) and hemolytic anemia with positive direct antiglobulin test (DAT or Coombs test) 1. A complete blood count will show decreased red blood cells and platelets, while additional tests may reveal elevated reticulocyte count, increased lactate dehydrogenase (LDH), decreased haptoglobin, and the presence of spherocytes on peripheral blood smear.
Key Diagnostic Criteria
- Low platelet count (thrombocytopenia)
- Hemolytic anemia with positive direct antiglobulin test (DAT or Coombs test)
- Elevated reticulocyte count
- Increased lactate dehydrogenase (LDH)
- Decreased haptoglobin
- Presence of spherocytes on peripheral blood smear
Additional Testing
Bone marrow examination is often performed to rule out other causes of cytopenias, typically showing normal or increased megakaryocytes and erythroid hyperplasia 1. Additional testing should include screening for underlying conditions that can cause Evan syndrome, such as systemic lupus erythematosus, common variable immunodeficiency, or lymphoproliferative disorders. This involves autoimmune panels, immunoglobulin levels, and sometimes imaging studies 1.
Challenges in Diagnosis
The diagnosis of Evan syndrome is challenging because it's a diagnosis of exclusion, requiring thorough investigation to rule out other causes of combined cytopenias before confirming Evan syndrome 1. The clinical presentation of Evan syndrome can vary widely, and the severity of thrombocytopenia correlates to some extent but not completely with the bleeding risk. Therefore, a comprehensive diagnostic approach is necessary to establish an accurate diagnosis and develop an effective treatment plan.
From the Research
Diagnosis of Evans Syndrome
The diagnosis of Evans syndrome is a complex process that requires the exclusion of other diseases causing anemia and thrombocytopenia 2. According to a study published in The Lancet. Haematology, the diagnosis involves extensive clinical and laboratory diagnostic tests, including bone marrow evaluation and CT scan 3.
Key Diagnostic Criteria
Some key diagnostic criteria for Evans syndrome include:
- Autoimmune hemolytic anemia and immune thrombocytopenia 4
- Positive direct anti-human globulin test 5
- Exclusion of other diseases causing hemolytic anemia and thrombocytopenia, such as thrombotic microangiopathies, anaemia due to bleedings complicating ITP, vitamin deficiencies, myelodysplastic syndromes, paroxysmal nocturnal haemoglobinuria, or specific conditions like HELLP when occurring during pregnancy 4
Diagnostic Challenges
The diagnosis of Evans syndrome can be challenging due to its rarity and the lack of a typical clinical presentation 2. A study published in the Journal of clinical medicine notes that the disease can be classified as primary or secondary to various conditions, including lymphoproliferative disorders, other systemic autoimmune diseases, and primary immunodeficiencies 4.
Laboratory Tests
Laboratory tests used to diagnose Evans syndrome include:
Importance of Early Diagnosis
Early diagnosis and treatment of Evans syndrome are crucial to prevent complications and improve patient outcomes 6. A study published in Blood advances found that adult Evans syndrome is often severe and marked by a relapsing clinical course and potentially fatal complications, highlighting the need for high clinical awareness and prompt therapy 6.