Eosinophilic heart disease in a paediatric patient

A 12-year-old child with no previous medical history was referred with a 4-day history of cough, shortness of breath, and peripheral blood eosinophilia. Transthoracic echocardiography showed a soft tissue infiltrating the left ventricular free wall, the lateral mitral annulus, and the mitral valve leaflets. A soft tissue strand connecting the lateral left atrial wall and mitral leaflets across the mitral valve orifice was also identified, causing reduced opening and functional mitral stenosis. The diagnosis of Löeffler endocarditis was made, and after 10 weeks of treatment with oral prednisolone, there was complete resolution of symptoms and of the infiltrative tissue with normalization of mitral valve function. The present case highlights some atypical features of eosinophilic heart disease-like occurrence in paediatric age, the complete preservation of the right ventricle and left ventricular apex, and the presentation with mitral stenosis compared with mitral regurgitation typically observed in the late phase of the disease.