[Non-infective endocarditis]. / Les endocardites non infectieuses.

Non-infective endocarditis, also referred to as non-bacterial thrombotic endocarditis, represent a wide range of rare pathologies, often severe. This review gathered the data available in the literature, to decipher the major information collected on the pathophysiology, the diagnosis and the treatment of these heterogeneous diseases, often misdiagnosed. Characteristics of non-infective endocarditis are similar to infective endocarditis in terms of valvular lesions (mostly left-sided, with regurgitations and vegetations), and their complications (embolism). The diagnosis of non-infective endocarditis is usually considered in patients with blood culture-negative endocarditis. Beyond the usual suspects - marastic endocarditis and systemic lupus erythematosus - which represent more than 75% of the cases, Behçet disease and hypereosinophilic syndrome are the main causes of non-infective endocarditis. More seldomly, rheumatoid arthritis, adult-onset Still disease, allergy to pork in patients with valvular procine bioprosthesis, systemic scleroderma, Cogan or Sneddon syndrome should be suspected. Diagnostic approach is based on history and physical examination, with a special focus on extra-cardiac manifestations, as well as echocardiography, and computed tomography. Treatment relies on intensive management of the underlying disease. Curative anticoagulation is often necessary. Although indications for cardiac surgery are poorly defined, as compared to infective endocarditis, data currently available suggest that an optimal control of the underlying disease before cardiac surgery is of utmost importance, as it dramatically reduces the risk of postoperative complications.

Update on blood culture-negative endocarditis.

Blood culture-negative endocarditis is often severe, and difficult to diagnose. The rate of non-documented infective endocarditis has decreased with the advent of molecular biology - improved performance for the diagnosis of bacterial endocarditis with blood cultures sterilized by previous antibacterial treatment - and cardiac surgery - access to the main infected focus, the endocardium, for half of the patients. Blood culture-negative endocarditis are classified in 3 main categories: (i) bacterial endocarditis with blood cultures sterilized by previous antibacterial treatment (usually due to usual endocarditis-causing bacteria, i.e. streptococci, more rarely staphylococci, or enterococci); (ii) endocarditis related to fastidious microorganisms (e.g. HACEK bacteria; defective streptococci - Gemella, Granulicatella, and Abiotrophia sp. - Propionibacterium acnes, Candida sp.): in these cases, prolonged incubation will allow identifying the causative pathogen in a few days; (iii) and the "true" blood culture-negative endocarditis, due to intra-cellular bacteria that cannot be routinely cultured in blood with currently available techniques: in France, these are most frequently Bartonella sp., Coxiella burnetti (both easily diagnosed by ad hoc serological tests), and Tropheryma whipplei (usually diagnosed by PCR on excised cardiac valve tissue). Non-infective endocarditis is rare, mostly limited to marantic endocarditis, and the rare endocarditis related to systemic diseases (lupus, Behçet).