Endocarditis: epidemiology, diagnosis and treatment.

The current incidence of infective endocarditis (IE) is estimated as seven cases per 100,000 population per year and continues to increase. The prognosis is significantly influenced by proper diagnosis and adequate therapy. In cases with unconfirmed IE, besides careful clinical examination, transesophageal echocardiography is the imaging technique of choice. Culture-negative endocarditis requires either termination of antimicrobial treatment initiated without microbiological test results and reevaluation of blood samples or serological/molecular biological techniques to identify the causative organism. Antimicrobial therapy should established only after quantitative sensitivity tests of antibiotics, including evaluation of the minimal bactericidal concentrations (MBC) of established combinations of antibiotics. Concomitant kidney involvement, a significant impairment of the hepatic function or the combination therapy with oto- and/or nephrotoxic antibiotics, requires drug monitoring. Large (> 10 mm) vegetations attached to the mitral valve are linked with a high incidence of thromboembolic complications. In most of these cases, the indication for surgical intervention is given, especially if the MBC of the optimal combination of antibiotics is high (> 2 micrograms/ml). In the first three weeks after primary manifestation of signs and symptoms of IE, an index embolism is frequently followed by recurrences. If vegetations can still be demonstrated by echocardiography after an embolic event, surgical intervention should seriously be considered. Cerebral embolic events are no contraindication for surgery with use of the heart-lung machine, as long as cerebral bleeding has been excluded by cranial computed tomography immediately preoperatively and the operation is performed before a significant disturbance of the blood-brain barrier (< 72 hours) has manifested. A significant prognostic improvement has also been demonstrated for patients with early surgical intervention, after their clinical course was complicated by myocardial failure due to acute valve incompetence, acute renal failure, mitral kissing vegetations in primary aortic valve IE, and in patients with sepsis persisting for more than 48 hours despite adequate antimicrobial therapy.