Abstract
BACKGROUND: Loeffler endocarditis is a relatively rare and potentially life-threatening heart disease. This study aimed to identify the characteristic features of Loeffler endocarditis with intracardiac thrombus on a background of hypereosinophilic syndrome (HES). CASE PRESENTATION: We described a 57-year-old woman with Loeffler endocarditis and intracardiac thrombus initially presenting with neurological symptoms, who had an embolic stroke in the setting of HES. After cardiac magnetic resonance (CMR), corticosteroids and warfarin were administered to control eosinophilia and thrombi, respectively. During a 10-month follow-up, the patient performed relatively well, with no adverse events. We also systematically searched PubMed and Embase for cases of Loeffler endocarditis with intracardiac thrombus published until July 2021. A total of 32 studies were eligible and included in our analysis. Further, 36.4% of recruited patients developed thromboembolic complications, and the mortality rate was relatively high (27.3%). CMR was a powerful noninvasive modality in providing diagnostic and follow-up information in these patients. Steroids were administered in 81.8% of patients, achieving a rapid decrease in the eosinophil count. Also, 69.7% of patients were treated with anticoagulant therapy, and the thrombus was completely resolved in 42.4% of patients. Heart failure and patients not treated with anticoagulation were associated with poor outcomes. CONCLUSIONS: Cardiac involvement in HES, especially Loeffler endocarditis with intracardiac thrombus, carries a pessimistic prognosis and significant mortality. Early steroids and anticoagulation therapy may be beneficial once a working diagnosis is established. Further studies are needed to provide evidence-based evidence for managing this uncommon manifestation of HES.