Approach to Suspected Hypereosinophilic Syndrome

A group of disorders characterized by abnormally high levels of eosinophils in the blood and tissues.

A specific type of HES where the elevated eosinophils are caused by a clonal proliferation of eosinophils, often associated with genetic abnormalities.

A type of HES where the elevated eosinophils are driven by a clonal or abnormal T-cell population.

A HES subtype encompassing conditions like eosinophilic gastroenteritis, eosinophilic granulomatosis with polyangiitis, and other entities that share overlapping features with idiopathic HES.

A HES subtype that occurs as a secondary manifestation of other disorders such as helminth infections, neoplasms, immunodeficiency, or hypersensitivity reactions.

A HES subtype where the elevated eosinophils are present in multiple family members without an underlying cause.

A HES subtype where the cause is unclear and other subtypes have been excluded.

A major cause of mortality in HES, affecting the heart through various mechanisms. Death is frequently due to dilated cardiomyopathy.

A common laboratory finding, defined as an absolute eosinophil count (AEC) greater than 0.45 x 10^9/L.

Elevated eosinophil count (AEC ≥ 1.5 x 10^9/L) that is extremely rare in the general population.

HES is a rare disorder with an estimated incidence of 0.315 to 6.3 per 100,000 in the United States.

HES can cause a wide range of symptoms, from mild fatigue to severe organ damage and life-threatening complications like endomyocardial fibrosis and thromboembolic events.

The World Health Organization (WHO) definition of HES requires an AEC > 1.5 x 10^9/L for more than 6 months, evidence of end-organ manifestations, and exclusion of reactive causes.

The consensus definition of HES involves two or more AEC measurements > 1.5 x 10^9/L at least one month apart, tissue eosinophilia, and organ damage or dysfunction.

A group of HES classified as idiopathic but typically caused by clonal/neoplastic eosinophils, often linked to mutations in genes like PDGFRA, PDGFRB, FGFR1, or PCM1-JAK2.

HES caused by factors other than clonal eosinophilia, often driven by cytokines due to various conditions like allergic reactions, parasitic infections, and autoimmune diseases.

HES that is inherited, highlighting a genetic predisposition to the disorder.

Atypical HES with clinical features resembling myeloproliferative neoplasms like chronic myeloid leukemia, but lacking the specific genetic abnormalities associated with these disorders.

HES associated with other hematologic cancers like acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML), typically involving rearrangements in genes like PDGFRA, PDGFRB, FGFR1, or PCM1-JAK2.

A subtype of HES characterized by male predominance, end organ damage, elevated serum tryptase, splenomegaly, anemia, thrombocytopenia, and bone marrow myeloproliferation with reticulin fibrosis. It's unresponsive to steroid therapy and is often associated with a specific genetic mutation.

A specific genetic alteration found in myeloproliferative variant HES, resulting in a fusion gene with enhanced tyrosine kinase activity. This fusion gene is particularly sensitive to low-dose imatinib therapy.

A subtype of HES characterized by a large population of CD2+ CD3– CD4+ T-cells that produce IL-4 and IL-5. It's equally frequent in males and females and often presents with skin manifestations.

The 'gold standard' for diagnosing LHES involves identifying a clonal and/or aberrant population of T-cells producing type 2 cytokines. However, this diagnostic tool is not readily available everywhere.

The diagnosis of LHES often relies on clinical presentation and evidence of a clonal and/or aberrant T-cell population in the peripheral blood.

In some cases, the surface phenotype of the clonal T-cell population in LHES can be indistinguishable from that seen in T-cell malignancies. Therefore, LHES is often a diagnosis of exclusion.

LHES can sometimes progress to lymphoid malignancy in a small percentage of patients, often after a period of stable disease.

A type of cytokine important in the pathogenesis of LHES. These cytokines, along with others, are produced by the aberrant T-cell population in LHES.

A crucial step to diagnose HES, involving a thorough examination of the patient's medical history, physical condition, and potential causes.

A blood test measuring the number and types of white blood cells (including eosinophils). Helps identify abnormalities in the blood cell composition and overall health.

A specialized test to assess the origin and nature of the abnormal T-cell population involved in Lymphocytic HES.

A procedure to analyze the surface features and behavior of lymphocytes (white blood cells) in the blood, helping to classify Lymphocytic HES subtypes.

Important to consider early in the diagnostic process because these usually require different treatment approaches.

The primary treatment for severe or life-threatening HES.

A condition where a specific type of white blood cell, called an eosinophil, is abnormally high in your blood and tissues and causes inflammation.

A rare disorder where the cause is unknown and other subtypes have been ruled out. It is often linked to mutations in specific genes.

The main treatment for HES is to reduce the number of eosinophils in the blood and tissues.

Medication that helps reduce eosinophil levels in the blood and tissues by targeting pathways that are critical to their survival.

A method of treating HES that involves administering interferon α, a protein that helps regulate the immune system, to reduce the number of eosinophils.

A measurement of the absolute number of eosinophils in a sample of blood, expressed in units per liter. It is used to assess the severity of eosinophilia.

The process of gradually decreasing the dosage of a medication over time. In HES treatment, this can be used to manage symptoms while also monitoring the effectiveness of the therapy.

A form of treatment that utilizes drugs like hydroxyurea to suppress the production of white blood cells, including eosinophils, potentially helping to manage HES.

A common symptom of HES, characterized by intense itching, which can often be severe and disruptive to daily life. It is triggered by the release of inflammatory mediators from eosinophils.