Discussion
There are obvious individual differences in the clinical manifestations of HES, ranging from asymptomatic, multiple organ involvement, and even death. This pathology may involve many organs and systems, such as the skin, lungs, nervous system, gastrointestinal tract, kidneys, and heart. Therefore, diagnosis may be a challenge. The main morbidity and mortality of HES patients are mostly cardiovascular complications.[2] Heart involvement may be present in 50% to 60% of patients, this is called Loffler endocarditis.
Due to infiltration and degranulation of eosinophils, toxic proteins are released, causing tissue inflammation and late fibrosis resulting in secondary damage to the myocardium and endocardium. It is usually characterized by thickening of the endocardium and dilation of the atrium. Doppler echocardiography can show hyperechoic mass in the heart cavity, suggesting fibrosis or thrombosis, and is often located in the apical area of the left and right ventricles. [3],[4]
Echocardiography and imaging studies may be the main tools for assessing cardiac anatomy and function. However, Loffler endocarditis requires pathological diagnosis, so endocardial biopsy remains the gold standard. In some cases, myocardial biopsy may be a dangerous operation. Therefore, clinicians should personally evaluate each individual before performing such invasive procedures. In addition, when evaluating the possibility of Loffler endocarditis, it is important to exclude the main differential diagnosis of HES, including hyper eosinophils secondary to hypersensitivity and parasitic infections. In this case, preoperative laboratory studies showed peripheral hyper eosinophilia and echocardiography showed typical intraventricular space-occupying changes. The diagnosis of Loffler endocarditis is basically established, and postoperative pathological specimens have confirmed the previous diagnosis. The pathological features of Loffler’s endocarditis include thickening of endocardial fibers, leading to a decrease in cardiac volume, thrombosis and restrictive cardiomyopathy. The clinical manifestations are heart failure, thromboembolic events and atrial fibrillation.
The main purpose of treatment is to reduce the level of eosinophils in peripheral blood and tissues, prevent terminal organ damage, and avoid the occurrence of adverse thrombotic events. Heart failure in Loffler’s endocarditis is mainly due to limited diastolic function of the heart. Treatment includes intravenous diuretics to reduce the preload of the heart. In addition, for symptomatic patients, the first-line drugs of choice are corticosteroids, followed by cytotoxic drugs such as hydroxyurea, and immunomodulators such as alpha-interferon. Glucocorticoid therapy is clinically proven to be effective for HES, which can improve the condition of myocardial injury and normalize peripheral hyper eosinophilia.[5],[6]
Secondary treatment should target cardiac complications such as heart failure and the presence of intracardiac thrombosis. Sometimes, cardiovascular complications require surgical treatment. Surgical experience is limited to cases where the heart valve function of patients due to HES is affected, but in more serious cases, acute surgical intervention may be necessary. In this case reported by our center, due to the large amount of thrombus tissue filling the right ventricle in a short time, the volume of the right ventricle was significantly reduced, the tricuspid valve was wrapped in the thrombus tissue, the opening of tricuspid valve was restricted, and there was a risk of pulmonary embolism caused by thrombosis. Therefore, the heart thrombus was removed under emergency cardiopulmonary bypass surgery.
Our patient had a good prognosis during the follow up of half year. She had no symptoms of heart failure and echocardiography findings were normal. This result might be due to the proper operation as well as the control of peripheral eosinophilia before and after the surgical procedure. Loffler endocarditis caused by hyper eosinophilia syndrome is unusual and fatal in children. The present case illustrates that with well controlled peripheral eosinophilia, proper surgical treatment in selected patients can improve their prognosis in the near future but long-term follow up is necessary.
Ethics approval This study has been approved by Medical Ethics Committee of Beijing Children’s Hospital, Capital Medical University and the composition and procedure of Medical Ethics Committee is accordance with GCP principal and national relevant laws and regulations
Number:2020-Z-062