Idiopathic hypereosinophilic syndrome: causes, symptoms, diagnosis, treatment

Idiopathic hypereosinophilic syndrome (disseminated eosinophilic collagenosis, eosinophilic leukemia, Loeffler fibroplastic endocarditis with eosinophilia) is a condition that is determined by eosinophilia of peripheral blood over 1500 / μL continuously for 6 months with the involvement or dysfunction of organs directly caused by eosinophilia in the absence of parasitic, allergic or other causes of eosinophilia. Symptoms are diverse and depend on the dysfunction of which organs is present. Treatment begins with prednisolone and may include hydroxyurea, interferon a and imatinib.

Only in individual patients with prolonged eosinophilia develops hypereosinophilic syndrome. Although it is possible to involve any organ in the process, the heart, lungs, spleen, skin and nervous system are usually affected. Involvement in the heart process is often the cause of heart pathology and death. As recently established, the hybrid tyrosine kinase, FIP1L1-PDGFR, is important in the pathophysiology of the process.

[1], [2], [3]

Symptoms of the idiopathic hypereosinophilic syndrome

Symptoms are diverse and depend on the dysfunction of which organs occurs .. Clinical symptoms are of two main types. The first type resembles a myeloproliferative disease with splenomegaly, thrombocytopenia, increased serum vitamin B ₁₂ levels and hypogranulation and vacuolization of eosinophils. In patients with this type, endomiocardial fibrosis or, more rarely, leukemia often develops. The second type has manifestations of hypersensitive type with angioneurotic edema, hypergammaglobulinemia, increased serum IgE levels and circulating immune complexes. Patients with this type of hypereosinophilic syndrome are less likely to develop heart disease requiring therapy, and a good response to glucocorticoids is noted.

Disturbances in patients with idiopathic thrombocytopenic syndrome

System	Occurrence	Manifestations
Constitutional	50%	Weakness, fatigue, anorexia, fever, weight loss, myalgia
Cardiopulmonary	> 70%	Restrictive or infiltrative cardiomyopathy, or mitral or tricuspid regurgitation with cough, dyspnea, heart failure, arrhythmias, endomyocardial disease, pulmonary infiltrates, pleural effusions, and parietal thrombi and emboli
Hematological	> 50%	Thromboembolic phenomenon, anemia, thrombocytopenia, lymphadenopathy, splenomegaly
Neurological	> 50%	Diffuse encephalopathy with impaired behavior, cognitive function and spastic syndrome, peripheral neuropathy, cerebral embolism with focal disturbances
Dermatological	> 50%	Dermographism, angioedema, rash, dermatitis
GIT	> 40%	Diarrhea, nausea, spasms
Immunological	50%	Increase of immunoglobulins (especially IgE), circulating immune complexes with serum sickness

[4], [5]

Diagnostics of the idiopathic hypereosinophilic syndrome

The diagnosis is suspected in patients with eosinophilia for no apparent reason and with symptoms suggesting organ dysfunction. Such patients should undergo a test with prednisolone in order to exclude secondary eosinophilia. It is necessary to carry out echocardiography to determine myocardial damage. A study of the general analysis and a blood smear helps to clarify which of the two types of eosinophilia takes place. In 1/3 patients with both types of eosinophilia, there is thrombocytopenia.

[6], [7], [8], [9], [10], [11], [12], [13]

Treatment of the idiopathic hypereosinophilic syndrome

There is no need for treatment until there are manifestations of organ dysfunction, for which the patient is examined every 2 months. Therapy is aimed at reducing the number of eosinophils based on the premise that the manifestations of the disease are the result of tissue infiltration by eosinophils or the release of their contents. Complications from local organ damage may require specific aggressive treatment (for example, damage to the heart valves may require replacement of the valves).

Therapy begins with the appointment of prednisolone 1 mg / kg until clinical improvement or normalization of the number of eosinophils is achieved. Adequate duration of therapy should be 2 months or more. When remission is reached, the dose slowly decreases over the next 2 months to a dose of 0.5 mg Dkgsut), then go on to receive 1 mg / kg every other day. Further reduction should be until the minimum dose that controls the disease is reached. If taking prednisolone for 2 months or more has not had an effect, higher doses of prednisolone are required. If you can not reduce the dose of prednisone without exacerbating the disease, hydroxyurea is added from 0.5 to 1.5 grams per day. The therapeutic goal is the level of eosinophils 4000-10 000 / μl.

Interferon can also be used in patients with prednisone inefficiency, especially in heart disease. The dose of 3 to 5 million units subcutaneously 3 times a week, depending on the clinical efficacy and tolerance to side effects. Termination of interferon therapy may lead to an exacerbation of the disease.

Imatinib, an oral inhibitor of pro-thekinase, is a promising treatment for eosinophilia. As it was demonstrated, such therapy normalized the number of eosinophils within 3 months in 9 of 11 treated patients.

Surgical and therapeutic treatment is necessary for signs of heart disease (eg, infiltrative cardiomyopathy, valve damage, heart failure). Thrombotic complications may require the appointment of antiplatelet agents (eg, aspirin, clopidogrel, ticlopidine); anticoagulants are indicated with parietal thrombosis of the left ventricle or transient ischemic attacks that do not respond to aspirin therapy.

Forecast

Hypereosinophilic syndrome has a poor prognosis, the cause of death is usually organ dysfunction. Constant therapy can improve prognosis.

[14], [15], [16], [17], [18]