Evans syndrome is an autoimmune condition with two or more cytopenias, usually caused by autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP), with or without immune neutropenia.
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Epidemiology
Evans syndrome is considered rare, with defining bicytopenias present in less than 5% of all patients diagnosed initially with either ITP or AIHA. The mean age at the time of diagnosis is 52 years, and it is slightly more common in females.
Clinical presentation
The clinical features of Evans syndrome are those of the bicytopenias and other hematopoietic cell lines affected. For example:
anemia: pallor, fatigue, jaundice, etc.
thrombocytopenia: easy bruising and bleeding, rarely more serious hemorrhage
neutropenia: increased risk and frequency of infections
Pathology
Etiology
Evans syndrome is generally sporadic, however, it can very rarely be inherited; familial Evans syndrome.
When sporadic, it is usually considered an idiopathic autoimmune condition against hematopoietic cells. When autoimmune hemolytic anemia is present, this is due to IgG antibodies reacting with red blood cell surface antigens at body temperature, and when immune thrombocytopenia is present, there are antibodies directed against GPIIb/IIIa on platelets.
Evans syndrome is often divided into either primary (idiopathic) or secondary forms. Secondary causes include:
viral infections (e.g. HIV, hepatitis C)
allogeneic hematopoietic stem cell transplantation
Treatment and prognosis
Management options include:
supportive care, e.g. blood transfusions
immunosuppression, e.g. corticosteroids, intravenous immunoglobulin, rituximab
Additionally, if Evans syndrome is a secondary phenomenon, management should also be directed towards the underlying cause.
History and etymology
Evans syndrome was first described in 1951 by the American hematologist Robert "Bud" Evans (1912-1974) and associates 2,3.