Hypereosinophilic syndrome
From Wikipedia, the free encyclopedia
| Hypereosinophilic syndrome Classification and external resources |
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| An eosinophil, the white blood cell involved in hypereosinophilic syndrome, seen amongst red blood cells. | |
| ICD-10 | D72.1 (ILDS D72.12) |
| ICD-9 | 288.3 |
| ICD-O: | 9964/3 |
| OMIM | 607685 |
| eMedicine | med/1076 derm/920 |
| MeSH | D017681 |
The hypereosinophilic syndrome (HS) is a disease process characterized by a persistently elevated eosinophil count (≥ 1500 eosinophils/mm³) in the blood for at least six months without any recognizable cause after a careful workup, with evidence of involvement of either the heart, nervous system, or bone marrow.[1] Although HS has no certain aetiology, evidence suggests a link with chronic eosinophilic leukemia[2] as it shows similar characteristics and genetic defects.[3] Recent studies have shown that Mepolizumab may be effective in treating patients with hypereosinophilic syndrome.[4]
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[edit] Classification
In the heart, there are two forms of the hypereosinophilic syndrome, endomyocardial fibrosis and Loeffler's endocarditis.
- Endomyocardial fibrosis (also known as Davies disease) is seen in Africa and South America.
- Loeffler's endocarditis does not have any geographic predisposition.
[edit] Signs and symptoms
As HS affects many organs at the same time, symptoms may be numerous. Some possible symptoms a patient may present with include:
[edit] Diagnosis
Numerous techniques are used to diagnose hypereosinophilic syndrome, of which the most important is blood testing. In HS, the eosinophil count is greater than 1.5 X 109/L.[3] On some smears the eosinophils may appear normal in appearance, but morphologic abnormalities, such as a lowering of granule numbers and size, can be observed.[3] Roughly 50% of patients with HS also have anaemia.[3]
Secondly, various imaging and diagnostic technological methods are utilised to detect defects to the heart and other organs, such as valvular dysfunction and arrhythmias by usage of echocardiography.[3] Chest radiographs may indicate pleural effusions and/or fibrosis[3], and neurological tests such as CT scans can show strokes and increased cerebrospinal fluid pressure.[3]
A proportion of patients have a mutation involving the PDGFRA and FIP1L1 genes on the fourth chromosome, leading to a tyrosine kinase fusion protein. Testing for this mutation is now routine practice, as its presence indicates response to imatinib, a tyrosine kinase inhibitor.[5]
[edit] Treatment
Treatment primarily consists of reducing eosinophil levels and preventing further damage to organs.[3] Corticosteroids, such as Prednisone, are good for reducing eosinophil levels and antineoplastics are useful for slowing eosinophil production.[3] Surgical therapy is rarely utilised, however splenectomy can reduce the pain due to spleen enlargement.[3] If damage to the heart (in particular the valves, then prosthetic valves can replace the current organic ones.[3] Follow-up care is vital for the survival of the patient, as such the patient should be checked for any signs of deterioration regularly.[3] After promising results in drug trials (95% efficiency in reducing blood eosinophil count to acceptable levels) it is hoped that in the future hypereosinophilic syndrome, and diseases related to eosinophils such as asthma and Churg-Strauss syndrome, may be treated with the monoclonal antibody Mepolizumab currently being developed to treat the disease.[4] If this becomes successful, it may be possible for corticosteroids to be eradicated and thus reduce the amount of side effects encountered.[4]
[edit] Epidemiology
HS is very rare, with only 50 cases being noted and followed up in the United States between 1971 and 1982.[3] The disease is even more uncommon within the paediatric population.[3]
Patients which lack chronic heart failure and those who respond well to Prednisone or a similar drug have a good prognosis.[3] However, the mortality rate falls in patients with anaemia, chromosomal abnormalities or a very high white blood cell count.[3]
[edit] References
- ^ Chusid MJ, Dale DC, West BC, Wolff SM (1975). "The hypereosinophilic syndrome: analysis of fourteen cases with review of the literature". Medicine (Baltimore) 54 (1): 1-27. PMID 1090795.
- ^ a b c d e f g h Longmore, Murray; Ian Wilkinson, Tom Turmezei, Chee Kay Cheung (2007). Oxford Handbook of Clinicial Medicine. Oxford, 316. ISBN 0-19-856837-1.
- ^ a b c d e f g h i j k l m n o p Rothenberg, Mark E. Treatment of Patients with the Hypereosinophilic Syndrome with Mepolizumab. Retrieved on 2008-03-17.
- ^ a b c Scheinfeld, Noah S. Hypereosinophilic Syndrome. Retrieved on 2008-02-15.
- ^ Cools J, DeAngelo DJ, Gotlib J, et al (2003). "A tyrosine kinase created by fusion of the PDGFRA and FIP1L1 genes as a therapeutic target of imatinib in idiopathic hypereosinophilic syndrome". N. Engl. J. Med. 348 (13): 1201-14. doi:. PMID 12660384.
