A hidden threat in the apical shadow: a case report regarding Loeffler endocarditis mimicking NSTEMI

Loeffler endocarditis (LE) is a rare but potentially life-threatening cardiac manifestation of hyper-eosinophilic syndrome (HES). The disease is often complicated by intracardiac thrombus formation and may lead to severe restrictive cardiomyopathy and thromboembolic events.

We report the case of a 71-year-old man with long-standing idiopathic hyper-eosinophilia who presented with chest pain and progressive dyspnoea. Cardiac MRI revealed apical endocardial fibrosis with intracavitary thrombus, confirming a diagnosis of Loeffler endocarditis. The patient was successfully treated with corticosteroids and anticoagulation with vitamin K antagonists.

This case highlights the diagnostic challenges and therapeutic strategies in managing LE. Cardiac MRI is essential for diagnosis, and early initiation of steroids and anticoagulation significantly improves clinical outcomes.