Current issues in the diagnosis and management of blood culture-negative infective and non-infective endocarditis.

Diagnosis and management of blood culture-negative endocarditis constitute a formidable clinical challenge and a systemic approach is necessary for a successful outcome. Blood cultures are negative in endocarditis due mainly to preceding antibiotic administration or to fastidious slow-growing organisms. Less so, non-infective endocarditis is a paraneoplastic manifestation or may occur in association with autoimmune diseases. When the clinical diagnosis is contemplated and cultures and serologies are negative, histologic and molecular examination of the removed valve tissue may confirm the diagnosis. Treatment with antibiotics is often warranted and valve replacement remains appropriate for patients with heart failure or irreversible structural damage.