Evans syndrome overview
Fizza Zulfiqar, MD

# Overview
Evans' Syndrome is an autoimmune disease in which an individual's antibodies attack their own RBCs as well as their platelets.  Its overall pathology is therefore effectively a combination of the two autoimmune induced conditions: autoimmune hemolytic anemia and immune thrombocytopenic purpura. 
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. Immune thrombocytopenic purpura is a condition in which the platelets in the blood 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. Patients with Evans syndrome usually appear normal. Physical examination of patients with Evans syndrome is usually remarkable for jaundice, hepatosplenomegaly, and lymphadenopathy.
Laboratory findings consistent with the diagnosis of Evans syndrome include anemia, direct coombs test positive, and antineutrophil antibody positive. Pharmacologic medical therapies for Evan's syndrome include prednisone, intravenous immunoglobulin, and rituximab. Surgery is not the firstline treatment option for patients with Evans syndrome. Splenectomy is usually reserved for patients who are unresponsive to treatment.

# Historical Perspective
Evans syndrome was first described by Dr. Robert S. Evans, an American physician, in 1951. Evans suggested that thrombocytopenia was likely due to an autoantibody directed against the platelets.

# Pathophysiology
The exact pathogenesis of Evans syndrome is not fully understood. It is thought that Evans syndrome is an autoimmune disorder in which autoantibodies are produced against red blood cells and platelets mainly, but also antibodies can be found against neutrophils and lymphocytes.It is also called "immune pancytopenia". On gross pathology, circumscribed mass with microscopic infiltration is a characteristic finding of Evans syndrome. On microscopic histopathological analysis, the alternating fibrous and myxoid stroma of low-grade/low malignant potential, and small tumor cells with scanty eosinophilic cytoplasm with a round to oval nuclei and no nucleoli are characteristic findings of Evans syndrome.

# Causes
The cause of Evans syndrome has not been identified. It is assumed that excess immune dysregulation is the probable cause of Evans Syndrome.

# Differential Evans Syndrome from Other Diseases
Evans syndrome must be differentiated from acquired thrombotic thrombocytopenic purpura, hemolytic-uremic syndrome, Kasabach-Merritt syndrome, fibromatosis, fibrosarcoma, myxofibrosarcoma, nodular fasciitis, and myxoid neurofibroma.
Other differential diagnosis includes: Vitamin defficiencies, Paroxysmal nocturnal hemoglobinuria (PNH) or HELLP (hemolysis-elevated liver enzymes - low platelets) seen in pregnancy.

# Epidemiology and Demographics
The incidence of Evans Syndrome is not precisely known. Evans Syndrome affects males and females equally. Evans Syndrome is a rare disease that tends to affect children.

# Risk Factors
Any history of malignancy, positive family history, and presence of the immune defect.

# Natural history, Complications and Prognosis
If left untreated, patients with Evans syndrome have periods of exacerbation. Common complications of Evans syndrome include thrombocytopenia and autoimmune hemolytic anemia. 
Depending on the extent of the tumor at the time of diagnosis, the prognosis may vary. However, the prognosis is generally regarded as good.

# Diagnosis

## History and Symptoms
Symptoms of Evans syndrome include breathlessness, fatigue, jaundice, dark urine, pallor, weakness, petechiae, ecchymosis, and epistaxis.
Due to prolonged immune suppressive therapies they are more prone to respiratory tract infections.

## Physical Examination
Patients with Evans syndrome usually appear normal. Physical examination of patients with Evans syndrome is usually remarkable for jaundice, hepatosplenomegaly, and lymphadenopathy.

## Laboratory Findings
Laboratory findings consistent with the diagnosis of Evans syndrome include anemia, direct Coombs test positive, and antineutrophil antibody positive.
Following tests are indicated for the diagnosis of Evans's syndrome:
Complete blood count,
Reticulocyte count,
Haptoglobin, LDH, indirect bilirubin,
Direct Antiglobulin Test,
Monoclonal Antibody Immobilization Platelet Assay (MAIPA),
Anti-neutrophil antibodies against CD16/FcRIII, CD11b, CD35/CR1, CD32/FcRII

# Treatment

## Medical Therapy
Pharmacologic medical therapies for Evans syndrome include corticosteroids (prednisone), intravenous immunoglobulin (IVIG), rituximab, anabolic steroids, vincristine, alkylating agents, or cyclosporine.Plasma exchange therapies have also been implicated in its treatment. Refractory disease can be treated by splenectomy and allogeneic hematopoietic stem cell transplant (HSCT).

## Surgery
Surgery is not the firstline treatment option for patients with Evans syndrome. Splenectomy is usually reserved for patients who are unresponsive to treatment.