Evans syndrome pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ammu Susheela, M.D. [2]
Overview
The exact pathogenesis of Evans syndrome is not fully understood. On gross pathology, circumscribed mass with microscopic infiltration is a characteristic finding of Evans syndrome. On microscopic histopathological analysis, alternating fibrous and myxoid stroma of low-grade/low malignant potential, and small tumor cells with scanty eiosinophilic cytoplasm wiht round to oval nuclei and no nucleoli are characteristic findings of Evans syndrome.
Pathogenesis
- Although Evans syndrome seems to be a disorder of immune regulation, the exact pathophysiology is unknown.
- Evans syndrome is an autoimmune disease in which an individual's antibodies attack their own red blood cells and platelets.[1] Both of these events may occur simultaneously or one may follow on from the other.[2]
- Pathophysiology of this disease involves decreased cluster of differentiation (CD)4+ T-helper cell counts, increased CD8+ T-suppressor cell counts, a decreased CD4/CD8 ratio, and reduced serum immunoglobulin G, M and A levels - indicating a complex immune dysregulation.
- Its overall pathology resembles a combination of autoimmune hemolytic anemia and idiopathic thrombocytopenic purpura.[1] Autoimmune hemolytic anemia is a condition in which the red blood cells that normally carry oxygen and carbon dioxide are destroyed by an autoimmune process. Idiopathic thrombocytopenic purpura is a condition in which platelets are destroyed by an autoimmune process. Platelets are a component of blood that contribute to the formation of blood clots in the body to prevent bleeding.
- It has been variously reported that between 10%[3] and 23%[4] of patients who have autoimmune hemolytic anemia, will also have thrombocytopenia and thus Evans syndrome. The two features may occur together or sequentially.[5]
- Depending on the pathophysiology, Evans syndrome is classified as primary and secondary.
Genetics
- There are no established causes for Evan's syndrome.Evans syndrome overlaps with autoimmune lymphoproliferative syndrome.
- Autoimmune lymphoproliferative syndrome is caused by a mutation in the tumor necrosis factor receptor gene superfamily member (TNFRSF6) also called CD95 or Fas gene.
Associated Conditions
- Autoimmune hemolytic anemia
- Idiopathic thrombocytopenia purpura
- Viral infection[6]
- Systemic lupus erythematosus
- Hashimoto’s thyroiditis
- Dermatomyositis
- Chronic inflammatory demyelinating polyneuropathy
- Autoimmune hepatitis
Gross Pathology
- Circumscribed mass, but microscopic infiltration
Microscopic Pathology
- Alternating fibrous and myxoid stroma of low-grade/low malignant potential
- Small tumor cells with scanty eiosinophilic cytoplasm, round to oval nuclei and no nucleoli.
References
- ↑ 1.0 1.1 Evans RS, Takahashi K, Duane RT, Payne R, Liu C (1951). "Primary thrombocytopenic purpura and acquired hemolytic anemia; evidence for a common etiology". A.M.AARRAYrchives of internal medicine. 87 (1): 48–65. PMID 14782741.
- ↑ Norton A, Roberts I (2006). "Management of Evans syndrome". Br. J. Haematol. 132 (2): 125–37. doi:10.1111/j.1365-2141.2005.05809.x. PMID 16398647.
- ↑ Template:GPnotebook
- ↑ Cai JR, Yu QZ, Zhang FQ (1989). "[Autoimmune hemolytic anemia: clinical analysis of 100 cases]". Zhonghua Nei Ke Za Zhi (in Chinese). 28 (11): 670–3, 701–2. PMID 2632179.
- ↑ Ng SC (1992). "Evans syndrome: a report on 12 patients". Clinical and laboratory haematology. 14 (3): 189–93. doi:10.1111/j.1365-2257.1992.tb00364.x. PMID 1451398.
- ↑ Simon, Ole; Kuhlmann, Tanja; Bittner, Stefan; Müller-Tidow, Carsten; Weigt, Jochen; Wiendl, Heinz; Meuth, Sven G (2013). "Evans syndrome associated with sterile inflammation of the central nervous system: a case report". Journal of Medical Case Reports. 7 (1): 262. doi:10.1186/1752-1947-7-262. ISSN 1752-1947.