Evans syndrome
| Evans syndrome | |
|---|---|
| Specialty | Hematology  |
Evans syndrome is an autoimmune disease in which an individual's immune system attacks their own red blood cells and platelets, the syndrome can include immune neutropenia.[1][2] These immune cytopenias may occur simultaneously or sequentially.[1][3]
Its overall phenotype resembles a combination of autoimmune hemolytic anemia and immune thrombocytopenic purpura.[1][4][5] Autoimmune hemolytic anemia is a condition in which the red blood cells that normally carry
The syndrome was first described in 1951 by R. S. Evans and colleagues.[1]
Signs and symptoms
The symptoms of Evans syndrome vary between patients depending on which blood cells are affected. If red blood cells are attacked, symptoms may include weakness and fatigue, paleness or jaundice, shortness of breath, lightheadedness, and/or a fast heartbeat. If platelets are attacked, symptoms may include increased bruising, prolonged nosebleeds, increased bleeding from minor cuts, and/or Petechiae. In the less common instance that white blood cells are attacked, symptoms may include increased proneness to infection, fevers, and/or mouth sores.[6][7]
It has been variously reported that between 7.8%[4] and 23%[8] of patients who have autoimmune hemolytic anemia, will also have thrombocytopenia and thus Evans syndrome. The two cytopenias may occur together or sequentially.[1][3][9]
Causes
Although Evans syndrome seems to be a disorder of immune regulation, the exact pathophysiology is unknown, but a gradual loss of self-tolerance is postulated.[5] Autoantibodies targeted at different antigenic determinants on red cells and platelets are assumed to cause isolated episodes of hemolytic anemia and thrombocytopenia, respectively.[10]
Diagnosis
Diagnosis of Evans syndrome is separated into primary and secondary presentation. There is no single test to confirm a diagnosis of either form of Evans syndrome. It is instead a diagnosis made after a thorough clinical history, documentation of common symptoms, clinical evaluation, and exclusion of all other possible conditions.[1]
The diagnosis of primary Evans syndrome is made upon blood tests to confirm not only hemolytic anemia and immune thrombocytopenic purpura, but also a positive direct antiglobulin test (DAT) and an absence of any known underlying cause.[3] Additional tests used to eliminate the possibility of other conditions include a computed tomography (CT) scan and a biopsy of bone marrow.[1]
A diagnosis of secondary Evans syndrome is indicative of occurrence after another autoimmune disease is already present.[11] In 27% to 50% of cases there is an associated malignancy or a predisposing autoimmune disease.[4][5][12] Pre-existing autoimmune diseases can include autoimmune lymphoproliferative syndrome (ALPS), combined variable immunodeficiency (CVID), systemic autoimmune disease, or another disorder of immune dysregulation.[13]
Other antibodies may occur directed against neutrophils and lymphocytes,[14] and "immunopancytopenia" has been suggested as an alternative term for this syndrome.[15]
Treatment
Initial treatment is with
The off-label use of rituximab (trade name Rituxan) has produced some good results in acute and refractory cases,[3][5][24][25] although further relapse may occur within a year.[3] Splenectomy is effective in some cases,[26] but relapses are not uncommon.[27]
The only prospect for a permanent cure is the high-risk option of an allogeneic hematopoietic
Prognosis
In a nationwide study of Evans syndrome the median survival was 7.2 years (primary Evans syndrome: 10.9 years; secondary Evans syndrome: 1.7 years). Secondary Evans syndrome was associated with higher mortality rate than primary Evans syndrome, with a 5-year survival of 38%. Among patients with Evans syndrome, the prevailing causes of death were bleeding, infections, and hematological cancer.[4]
It has been observed that there is a risk of developing other autoimmune problems and
Epidemiology
Evans syndrome is considered a very rare autoimmune disease. Only one study has estimated incidence and prevalence adults. In Denmark in 2016 the annual incidence was 1.8 per 1,000,000 person years, and the prevalence was 21.3 per 1,000,000 living persons.[4] In pre-pubertal children the incidence has been estimated to be between 0.7 and 1.2 per 1,000,000 person-years.[32][33]
See also
References
- ^ a b c d e f g "Evans Syndrome". NORD (National Organization for Rare Disorders). Retrieved 2022-03-15.
- ^ "Evans syndrome". Genetic and Rare Diseases Information Center. Retrieved 2018-04-17.
- ^ S2CID 7633446.
- ^ S2CID 195879785.
- ^ PMID 19638626.
- ^ "Evans syndrome | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program". rarediseases.info.nih.gov. Retrieved 2020-11-27.
- ^ "Evans Syndrome | Symptoms & Causes | Boston Children's Hospital". www.childrenshospital.org. Retrieved 2020-11-27.
- PMID 2632179.
- PMID 1451398.
- ^ "EVANS SYNDROME". 2019-10-22.
{{cite journal}}: Cite journal requires|journal=(help) - S2CID 46891351.
- ^ "Evans syndrome". Genetic and Rare Diseases Information Center. Retrieved 2019-07-28.
- S2CID 46891351.
- PMID 7104228.
- PMID 7191890.
- S2CID 19749102.
- PMID 1483999.
- ^ "Evan's Syndrome". Boston Children's Hospital. Retrieved 2020-11-23.
- S2CID 11724766.
- PMID 11855146.
- PMID 1404865.
- PMID 8492411.
- S2CID 20968070.
- PMID 12531800.
- PMID 14601692. Archived from the original(PDF) on 2006-03-13. Retrieved 2007-04-18.
- PMID 16124452.
- S2CID 24014798.
- PMID 9313889.
- PMID 11781654.
- S2CID 20125761.
- PMID 15542578.
- PMID 32271826.
- PMID 32271826.