**2. Main etiologies of BCNIE**

There are three main causes for BCNIE.


If all microbiological assays are negative, noninfective endocarditis is considered, and systematically differential diagnosis should be performed. Nonbacterial thrombotic endocarditis (marantic endocarditis) in patients with malignant tumor and systemic diseases such as SLE and Behҫet are two main causes of noninfective endocarditis.
