Endocarditis

Endocarditis is an inflammation of the endocardium, the membrane lining the chambers of the heart and covering the cusps of the heart valves. Infective endocarditis (IE) refers to infection of the heart valves by microorganisms, primarily bacteria. 

Endocarditis is often referred to as either acute or subacute depending on the clinical presentation. Acute bacterial endocarditis is a Mminating infection associated with high fevers, systemic toxicity, and death within days to weeks if untreated. Subacute infectious endocarditis is a more indolent infection, usually occurring in a setting of prior valvular heart disease. 

Most patients with IE have risk factors, such as preexisting cardiac valve abnormalities. 

Most types of structural heart disease resulting in turbulence of blood flow will increase the risk for IE. Some of the most important risk factors include / Presence of a prosthetic valve (highest risk) 

Three groups of organisms cause most cases of IE streptococci (60% to 80%), staphylococci (20% to 35%), and enterococci (5% to 18%) (Table 37-1). 

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Tuberculosis is on the increase in developed countries such as the USA and UK furthermore, MAI may be associated with AIDS sufferers. Hospital-acquired opportunistic mycobacteria may cause disseminated infection and also lung infections, endocarditis and pericarditis. Transmission of mycobacterial infection by endoscopy is rare, despite a marked increase in the use of flexible fibreoptic endoscopes, but bronchoscopy is probably the greatest hazard for the transmission ofM tuberculosis and other mycobacteria. Thus, biocides used for bronchoscope disinfection must be ehosen carefully to ensure that such transmission does not occur. 

Ischemic stroke has numerous causes. Cerebral infarction may result from large artery atherosclerosis, cardiac embolism, small artery lipohyalinosis, cryptogenic embolism, or, more rarely, from other diverse conditions such as arterial dissection, infective endocarditis, and sickle cell disease. Arterial occlusion is the cause of at least 80% of acute cerebral infarctions. " ... 

Based primarily on the study protocol of the 1995 NINDS rt-PA study.Many centers would also exclude patients with known documented endocarditis or aortic dissection, and those with CT hypoattenuation in more than one third of the middle cerebral artery territory. There are insufficient data to support the use of rt-PA for ischemic stroke in pregnancy or in the pediatric population (age <18 years). 

Hart RG, Foster JW, Luther MF, Kanter MC. Stroke in infective endocarditis. Stroke 1990 21 695-700. 

Evidence of active pericarditis, endocarditis, septic emboli, current or recent pregnancy, and lactating women... 

Antimicrobials also can be classified as possessing bactericidal or bacteriostatic activity in vitro. Bactericidal antibiotics generally kill at least 99.9% (3 log reduction) of a bacterial population, whereas bacteriostatic antibiotics possess antimicrobial activity but reduce bacterial load by less than 3 logs. Clinically, bactericidal antibiotics may be necessary to achieve success in infections such as endocarditis or meningitis. A full discussion of the application of antimicrobial pharmacodynamics is beyond the scope of this chapter, but excellent sources of information are available.15... 

Reculture of specimens is not performed routinely except in few cases (e.g., endocarditis) or where a secondary infection is suspected because data may be misleading and lead to the addition of broader or more powerful antimicrobials... 

Baddour LM, Wilson WR, Bayer AS, et al. Infective endocarditis Diagnosis, antimicrobial therapy, and management of complications a statement for healthcare professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, and the Councils on Clinical Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia, American Heart Association endorsed by the Infectious Diseases Society of America. Circulation 2005 111(23) 394M34. 

A secondary goal of therapy for larger furuncles and all carbuncles is to minimize the risk of endocarditis or osteomyelitis by reducing bloodstream invasion. 

O For infective endocarditis to develop, the occurrence of several factors is required. These factors involve alterations to the endocardial surface that allow for bacterial adherence and eventual infection. 

Infective endocarditis (IE) is a serious infection affecting the lining and valves of the heart. While this disease is mostly associated with infection of the heart valves, the septal defects may become involved as well. Infections also occur in patients with prosthetic or mechanical devices, such as mechanical heart valves or who are intravenous drug users (IVDUs). Bacteria is the primary cause of IE however, fungi and atypical organisms also can be responsible pathogens. 

Reprinted from Bayer AS, Scheld WM, Endocarditis and intravascular infections. In Principles and Practice of Infectious Diseases, Vol 1, 5th ed., p. 870. Copyright 2000, with permission from Elsevier. 

FIGURE 71-1. Pathogenesis of infective endocarditis. (From Scheld W. In Atlas of Infectious Diseases External Manifestations of Systemic Infections. Philadelphia Current Medicine, Inc. Copyright 1997. Used with permission.)... 

Infective endocarditis caused by these streptococci typically has a subacute clinical course. The current cure rate is often over 90% unless complications occur, which is the case in more than 30% of patients.17 The majority of viridans streptococci remain very susceptible to penicillin, with most strains having a minimum inhibitory concentration (MIC) of less than 0.125 mcg/mL.15,18 Organisms with decreased susceptibilities are increasing. Therefore, antibiotic susceptibilities need to be assessed in order to determine the most appropriate treatment regimen. 

Staphylococcal endocarditis is increasing in prevalence, causing a minimum of 20% to 30% of all cases of IE, with the majority (80%—90%) being due to S. aureus (also known as... 

B. Modified Duke Criteria for the Diagnosis of Infective Endocarditis ... 

Pathologic lesions vegetation or intracardiac abscess confirmed by histologic examination showing active endocarditis Clinical criteria ... 

Firm alternate diagnosis explaining evidence of infective endocarditis, or... 

Resolution of infective endocarditis syndrome with antibiotic therapy for less than or equal to 4 days, or... 

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