idiopathic hypereosinophilic syndrome

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Idiopathic hypereosinophilic syndrome (IHES) is a leukoproliferative disorder and refers to a situation when there is an unexplained prolonged eosinophilia with associated organ system dysfunction. The condition can affect several organ systems which includes:

heart: cardiac involvement in idiopathic hypereosinophilic syndrome
- the heart can be a commonly involved organ
- has three stages and can cause
  - eosinophillic endocarditis (Loeffler endocarditis)
  - restrictive cardiomyopathy
  - valvular damage
  - mural thrombus formation
  - endomyocardial fibrosis
lung: pulmonary involvement in idiopathic hypereosinophilic syndrome
- can occur in up to 40% of cases
- pulmonary manifestations are sometimes categorized under the spectrum of eosinophilic lung disease
central nervous system: CNS involvement in idiopathic hypereosinophilic syndrome
peripheral nervous system: peripheral nervous system involvement in idiopathic hypereosinophilic syndrome
eyes: ocular involvement in idiopathic hypereosinophilic syndrome
joints: rarely seen rheumatological manifastations of idiopathic hypereosinophilic syndrome

Pathology

Individuals have prolonged raised total leukocyte counts with raised eosinophil counts. Usually the total leukocyte counts are less than 25,000/μL with 30-70% comprising of eosinophils. At times extremely high leukocyte counts (>90,000/μL) can also develop which can then result in a poorer prognosis.