hematology and oncology
Hypereosinophilic Syndrome
Key Points
Hypereosinophilic syndrome is peripheral blood eosinophilia (>1500/mcL [> 1.5 × 109/L]) not caused by parasitic, allergic, or other secondary causes of eosinophilia, that has persisted≥6 months and caused organ damage or dysfunction. Hypereosinophilic syndrome appears to be a manifestation of a number of hematopoietic disorders, some of which have a genetic cause. Any organ may be involved but the heart, lungs, spleen, skin, and nervous system are typically affected; cardiac involvement can cause significant morbidity and mortality. Do tests for organ involvement, including liver enzymes; creatine kinase, creatinine, and troponin levels; ECG and echocardiography; pulmonary function tests; and CT of the chest, abdomen, and pelvis. Do bone marrow examination with cytogenetic testing to identify a cause. Give corticosteroids for severe eosinophilia and/or organ damage. Tyrosine kinase inhibitors such as low-doseimatinibmay be of benefit in subtypes associated with distinct chromosomal abnormalities. 