الفهرس 
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Abstract
Infective endocarditis (IE) is defined as a focus of infection within the Heart and one of the most feared diseases across the field of cardiology. IE affects about 3–10 per 100,000 persons per year Despite major advances in diagnostic and therapeutic procedures, the prognosis is poor with a 1-year mortality approaching 30% and high complication rates at long term Thus, there is a need for improved early diagnosis and optimal management of IE.
Management of patients with IE is a difficult challenge and requires an appropriate infrastructure and the involvement of multiple hospital specialists including cardiologists, surgeons, infectious disease physicians, microbiologists, nephrologists, neurologists and radiologists.
Anti-microbial prophylaxis regimens have been modified across the last decades and the concept of antibiotics to prevent IE has changed considerably since it was first formally introduced in the AHA guidelines of 1955. Dose and administration regimens have become simpler and shorter, and the number of individuals and procedures where prophylactic antibiotics is recommended has significantly reduced. Virtually all guideline committees around the world recommend AP for high-risk individuals undergoing high-risk invasive dental procedures.
Reaching a rapid and accurate diagnosis in cases of suspected IE is a central challenge of the disease. Delayed diagnosis and initiation of therapy lead to complications and worse clinical outcome.
Clinical presentation is very diverse, ranging in signs and symptoms from acute sepsis and an indolent low-grade febrile illness to a heart failure syndrome or stroke. The modified Duke criteria were used for diagnosis of IE but it appeared to have a lower sensitivity for patients with prosthetic valve endocarditis (PVE) or cardiac device infection.
In fact according to Duke Criteria Up to 30% of patients with subsequently proven IE are labeled as ―possible‖ due to negative findings on echocardiography or blood cultures, Key advances have been made in recent years in reaching a definitive diagnosis in patients who fall into the ―possible‖ group according to the Duke criteria.
New imaging techniques have provided more specific methods for early detection and proper management of infective endocarditis.
The recent updates of infective endocarditis according to the European society of cardiology (ESC) 2015 Guidelines and a 2017 focus update of American Heart Association (AHA) is listed below:
1) updates in risk factor :
a. Patients with a prosthetic valve or with prosthetic material used for cardiac valve repair these patients have a higher risk of IE.
b. Patients with previous IE.
c. Patients with untreated cyanotic congenital heart disease (CHD) and those with CHD who have postoperative palliative shunts, conduits or other prostheses
2) updates in pathophysiology :
Antibodies against cell-surface components reduce adhesion of C.albicans to fibrin and platelets in vitro and reduce incidence of IE in vivo, In addition, when administered in conjunction with antibiotic therapy, antibodies specific for the fibrinogen-binding protein clumping factor A (ClfA) increased bacterial clearance from vegetations. Moreover, recent data suggest a possible role for vaccination against ClfA for the prevention of IE.
3) updates in diagnosis of complications:
Both overt and clinical silent central nervous system embolism are common complications of IE, patients and silent embolism needs further imaging tools for examination. Recently some new biological markers, such as S-100B is used to predict embolism in central nervous system during the course of IE.
4) updates in diagnostic imaging :
a. Cardiac computed tomography (CT) scanning is the key adjunctive modality for use when the anatomy is not clearly delineated according to echocardiography and it now has a Class II Level of Evidence: B recommendation for use in IE in the 2014 ACC/AHA valvular heart disease guidelines .Cardiac CT is equivalent and possibly superior to TEE for demonstrating paravalvular anatomy and complications.
b. CT angiography allows exclusion of significant coronary disease in younger patients. Detection of paravalvular lesions by using CT imaging is now a major diagnostic criterion in the 2015 European Society OF Cardiology (ESC) guidelines on IE.
c. Combining CT imaging with metabolic imaging by 18-fluorodeoxyglucose positron emission tomography (18FDG-PET) or leukocyte scintigraphy (radiolabeled leukocyte single-photon emission computed tomography [SPECT]) to show regions of metabolic activity or inflammation, respectively, is a hugely promising approach in patients who according to the Duke criteria have ―possible‖ IE or suspected CDI . Several studies have now investigated the sensitivity and specificity of PET/CT or SPECT/CT imaging in this setting. In a cohort of 72 patients with suspected PVE, 18FDG PET/CT imaging had an overall sensitivity of 73% and a specificity of 80%.
5) updates in microbiological investigations: Negative results on blood cultures may occur due to previous antibiotic use, infection with fastidious intracellular organisms or fungi or an alternative diagnosis. The incidence of blood culture–negative IE may DROP with increasing use of newer blood culture techniques which allow direct identification of bacterial species by mass spectroscopy are significantly faster than standard culture methods .
6) updates in prophylactic treatment:
a. In 2017, the AHA and American College of Cardiology (ACC) published a focused update to their previous guidelines on the management of valvular heart disease. This reinforced their previous recommendations that AP is reasonable for the subset of patients at increased risk of developing IE and at high risk of experiencing adverse outcomes from IE.
b. In the event that the dosage of antibiotic is inadvertently not administered before the procedure, it may be administered up to two hours after the procedure.
c. For patients already receiving an antibiotic that is also recommended for IE prophylaxis, then a drug should be selected from a different class for example, a patient already taking oral penicillin for other purposes may likely have in their oral cavity viridans group streptococci that are relatively resistant to beta-lactams In these situations, clindamycin, azithromycin or clarithromycin would be recommended for AP
7) updates in general principles of medical treatment :
a. In NVE needing valve replacement by prosthesis during antibiotic Therapy, the postoperative antibiotic regimen should be that recommended for NVE, not for PVE. In both NVE and PVE, the duration of treatment is based on the first day of effective antibiotic therapy (negative blood culture in the case of initial positive blood culture), not on the day of surgery.
b. The indications and pattern of use of aminoglycosides have changed. They are no longer recommended in staphylococcal NVE because their clinical benefits have not been demonstrated, but they can increase renal toxicity and when they are indicated in other conditions, aminoglycosides should be given in a single daily dose to reduce nephrotoxicity.
c. Rifampin should be used only in foreign body infections such as PVE after 3–5 days of effective antibiotic therapy.
8) updates of surgical treatment :
a. Aortic or mitral NVE or PVE with severe regurgitation or obstruction causing symptoms of HF or echocardiographic signs of poor hemodynamic tolerance must be treated by urgent surgery.
b. Locally uncontrolled infection (abscess, false aneurysm, fistula, enlarging vegetation) must be treated by urgent surgery.
c. Infection caused by fungi or multiresistant organisms must be treated by urgent surgery.
d. Aortic or mitral NVE or PVE with persistent vegetations 10 mm after ≥1 embolic episodes despite appropriate antibiotic therapy must be treated by urgent surgery.
Successful Management of IE includes Prompt diagnosis and institution of effective antimicrobial (prophylactic and therapeutic) therapy to reduce the risk of complications and development of indications for surgery, Assessment of need for removal of any infected implanted devices or atrioventricular shunts, Identification of patients with an indication for early valve surgery, Follow-up and prevention of recurrent IE (including good dental hygiene, antimicrobial prophylaxis, and closure of patent ductus arteriosus or ventricular septal defect, if present.