HES is a syndrome (i.e., a collection of similar
entities), not a disease, characterized by the simultaneous existence of (1)
eosinophil count greater than 1500/mm3 for more than 6 months, (2)
absence of any known cause of eosinophilia, and (3) existence of symptoms of
organ involvement (benign eosinophilia is excluded).
Idiopathic Hypereosinophilic Syndrome.
Leukoproliferative disorder of unknown origin
characterized by overproduction of eosinophils that results in multiple
organ damage. First described by Hardy and Anderson in 1968.
Not known but rare. No racial predilection is reported,
but male-to-female ratio is 9:1 (male predominance). Survival rate is 80%
at 5 years and 42% at 10 years.
The etiology of this syndrome is unknown, but it
is characterized by proliferation of eosinophils. These cells damage tissue,
especially cardiac and neural tissue, by release of peroxidase and
neurotoxin. The production of eosinophil is regulated by several cytokines
(IL-3, GM-CSF, IL-5). Usually, eosinophils reach areas of inflammation and
quickly undergo apoptosis after degranulation. In HES, eosinophils survive
longer in the tissues, thus increasing the amount of damage they can inflict
because they store (and release) toxic cationic proteins, which are the
primary mediators of tissue damage. The most serious complication of HES is
cardiac involvement (myocardial fibrosis and congestive heart failure);
however, hypereosinophilia alone is insufficient to cause cardiac damage.
Leukocytosis with eosinophilia. Bone marrow examination
is required to rule out eosinophilic leukemia. Treatable parasitic
infections must be sought. Some cases previously diagnosed as HES involved
malignant transformation of eosinophils, but these constitute a minority and
malignant evolution and are not a feature of HES.
HES is a heterogenous disease process.
Multiple clinical manifestations may occur simultaneously or individually.
Central nervous system (CNS) dysfunction (confusion, delirium, coma, dementia), congestive heart
failure, arrhythmias, pulmonary infiltrates/effusion, nonproductive cough,
hepatosplenomegaly, anemia and/or thrombocytopenia, anorexia, weight loss,
fatigue, nausea, abdominal pain, diarrhea, pruritic rash, fever, night
sweats, hepatosplenomegaly, peripheral neuritis, and venous thrombosis. Most
commonly diagnosed between 20 and 50 years of age; rare in children.
Baseline neurologic examination
must be obtained. Evaluate for cardiac dysfunction and arrhythmia. Review
baseline chest radiographs, ECG,
cell blood count (CBC), and liver function. Echocardiography
Avoid regional anesthesia
if thrombocytopenia is present.
Avoid myocardial depressants.
Prophylaxis against thrombosis postoperatively.
Other syndromes with
eosinophilia, especially the following:
Churg-Strauss Syndrome (Allergic Granulomatous Angiitis):
Autoimmune disorder affecting smallto medium-sized arteries and veins,
associated with antibodies to neutrophil cytoplasmic antigens; symptoms
include asthma, asthenia, weight loss, fever, purpura, eosinophilia, anemia,
and multivisceral disorders.
Eosinophilia-Myalgia Syndrome: Multisystemic, chronic, autoimmune
disease caused by ingestion of impure l-tryptophan (usually ingested
as an amino acid dietary supplement).
Kimura Disease: Chronic inflammatory disorder of unknown origin,
characterized by solitary or multiple nonpainful subcutaneous nodules
located on the head or neck with peripheral ...