Study objectivesThe primary objective of our study is to assess the endocarditis prevalence in patients admitted to the emergency department (ED) for a primary diagnosis of acute stroke (AS). Secondary objectives are the identification of early markers of endocarditis in AS patients and the analysis of the short-term outcome of this population. MethodsIn this observational, retrospective, cohort study we enrolled consecutive adult patients with a primary diagnosis of AS admitted to the Stroke Unit or to the Neurological Intensive Care Unit of our hospital who were then discharged with a diagnosis of endocarditis. These patients were then compared with age and sex-matched controls with a diagnosis of AS and atrial fibrillation. ResultsEndocarditis prevalence in patients admitted to the Stroke Unit or Neurological Intensive Care Unit with a primary diagnosis of AS is 1.0% (95% confidence interval 0.61-1.55). Fever on ED admission, concomitant cancer, low hemoglobin, low lymphocyte levels, a high neutrophils count and erythrocyte sedimentation levels could early differentiate among AS patients, those with endocarditis from those with atrial fibrillation. A moderate-to-severe valvular regurgitation is strongly suggestive of endocarditis. The short term-outcome is markedly worse in endocarditis patients compared to patients with atrial fibrillation, in terms of in-hospital mortality and discharge disability. ConclusionsEndocarditis prevalence in patients admitted for a primary diagnosis of AS is low, but this etiology leads to a poor outcome. Some laboratory, clinical-epidemiological and echocardiographic parameters may help the physician to early recognize this condition and, consequently, to promptly start an antibiotic therapy.