Case report: Different clinical manifestations of the rare Loeffler endocarditis.

Background: Loeffler endocarditis is a rare and fatal disease, which is prone to be misdiagnosed, owing to its various clinical manifestations. Consequently, an early identification of Loeffler endocarditis and its effective treatment are crucial steps to be undertaken for good prognosis. Case presentation: This report describes two cases of Loeffler endocarditis with different etiologies and clinical manifestations. Case 1 was caused by idiopathic eosinophilia and presented with a thrombus involving the tricuspid valve and right ventricular inflow tract (RVIT). The patient suffered from recurrent syncope following activity. After the patient underwent tricuspid valve replacement and thrombectomy, he took oral prednisone and warfarin for 2 years, consequent to which he discontinued both drugs. However, the disease recurred 6 months later, this time manifesting as edema of both legs. Echocardiography showed that a thrombus had reappeared in the RVIT. Thus, oral prednisone and warfarin therapy was readministered. Three months later, the thrombus had dissolved. Low-dose prednisone maintenance therapy was provided long term. Case 2 involved a patient who presented with recurrent fever, tightness in the chest, and asthma, and whose condition could not be confirmed, despite multiple local hospitalizations. In our hospital, echocardiography revealed biventricular apical thrombi. After comprehensive examinations, the final diagnosis was eosinophilic granulomatosis polyangiitis (EGPA) involving multiple organs, including the heart (Loeffler endocarditis), lungs, and kidneys. After administration of corticosteroid, anticoagulant, and immunosuppressive agents along with drugs to improve cardiac function, the patient's symptoms improved significantly. Conclusion: In Loeffler endocarditis due to idiopathic eosinophilia, long-term corticosteroid use may be required. Diverse and non-specific symptoms cause Loeffler endocarditis to be easily misdiagnosed. So, when a patient shows a persistent elevation of the eosinophil count with non-specific myocardial damage, the possibility of this disease, should always be considered. Furthermore, even when an invasive clinical procedure such as endomyocardial biopsy (EMB) is not available or acceptable, corticosteroids should be administered promptly to bring the eosinophil count back to the normal range, thereby halting the progression of disease and reducing patient mortality.