Group of diseases characterized by the presence of blood eosinophilia ≥ 1,500/mm3 associated with tissular involvement related to eosinophilic infiltration.

Different entities have been identified:

-        chronic eosinophilic leukemia (CEL); which is part of the primary or clonal SHE,

1)        myeloproliferative variant: anemia, thrombocytopenia, splenomegaly, myelofibrosis. Often associated to endomyocardial fibrosis.  It can evolve into acute myeloid leukemia or acute lymphoblastic leukemia. Cytogenetic abnormalities: fusion gene FIP1L1/PDGFRA ,  platelet derived growth factor receptor beta (PDGFRB), rearrangement of fibroblast growth factor receptor 1 (FGFR1) or Janus kinase 2 (PCM1-JAK2) gene. Favorable response to tyrosine kinase inhibitors (imatinib)

2)        lymphoproliferative variant: associated with a clonal population of T cells with an aberrant phenotype. Clinical presentation: angioedema and/or skin abnormalities, circulating immune complexes (sometimes with serum disease), hypergammaglobulinemia (high IgE). Favorable response to corticosteroids but sometimes development of T-cell lymphoma

-         reactive eosinophilic syndrome (SHE-R); eosinophilia is secondary to an increased production of eosinophilopoietins (including IL-5). The cause may be  iatrogenic (drug hypersensitivity syndrome, DRESS), parasitic infection (helminthiasis), solid or hematological neoplasia (Hodgkin's lymphoma, T-cell lymphomas)

-        lymphoid eosinophilic syndrome (SHE-L);  proliferation of a T lymphocyte population with aberrant phenotype (including CD3-CD4+)

-        idiopathic eosinophilic syndrome (SHE-I): undetermined origin

-        organ-specific eosinophilic diseases (eosinophilic myocarditis, eosinophilic gastroenteritis, acute and/or chronic eosinophilic pneumonitis, episodic angioedema with eosinophilia);

-        eosinophilic granulomatosis with polyangiitis (GEPA or Churg-Strauss syndrome) (see this term)

-        Gleich syndrome: cyclic eosinophilia and angioedema, benign course

-        familial hypereosinophilic syndromes linked with 5q31-33 (genetic predisposition to asthma and atopy?)

Complications: massive degranulation of eosinophils, vasculitis, release of procoagulants, thrombosis with risk of embolism

Treatment: the emergency management of the severe visceral involvement related to eosinophilic toxicity is based on corticosteroid therapy. SHE-R and SHE-I are generally very cortico-sensitive but interferon-alfa or hydroxyurea are sometimes necessary. Background treatment for CEL is based on tyrosine kinase (imatinib) inhibitors.

Anesthetic implications:

check the total blood count; side effects and interactions of the current treatments (corticosteroids, inhibitors ...)

References : 

Updated: July 2022