- Subacute bacterial endocarditis
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ICD10 = ICD10|I|33|0|i|30
ICD9 = ICD9|421.0
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MeshID = D004698Subacute bacterial endocarditis (also called endocarditis lenta) is a type of
endocarditis (more specifically, infective endocarditis).It can be confused with
essential mixed cryoglobulinemia .cite journal |author=Agarwal A, Clements J, Sedmak DD, "et al" |title=Subacute bacterial endocarditis masquerading as type III essential mixed cryoglobulinemia |journal=J. Am. Soc. Nephrol. |volume=8 |issue=12 |pages=1971–6 |year=1997 |month=December |pmid=9402102 |doi= |url=http://jasn.asnjournals.org/cgi/pmidlookup?view=long&pmid=9402102]It can be considered a form of
Type III hypersensitivity .cite web |url=http://128.240.24.212/cgi-bin/omd?type+III+hypersensitivity+reaction |title=Definition: immune complex disease from Online Medical Dictionary |format= |work= |accessdate=]Causes
It is usually caused by
Streptococcus viridans , a member of the normalmicroflora of bacteria that live in the mouth and throat. Other strains of streptococci can also cause disease, along with the so-called HACEK group of bacterial species;Haemophilus ,Actinobacillus ,Cardiobacterium ,Eikenella andKingella . These organisms are all low virulence and can only colonise the heart valves when they are congenitally malformed like abicuspid aortic valve , or when they have been disrupted by certain pathologies as seen inRheumatic fever .Diagnosis
Common symptoms include malaise, PUO (Pyrexia of Unknown Origin, often not present in the elderly), and change in nature of
heart murmur .Testing will sometimes show a raised
CRP andESR , with blood cultures being occasionally positive for anaerobic bacteria. Patients may also showthrombocytopenia . If a good history is taken then subacute bacterial endocarditis should be suspected immediately. A combination of previous diagnosis ofRheumatic fever or aheart murmur , and recent surgical dental procedure or suffered trauma to the oral cavity is often helpful in determinig the diagnosis. An ultrasound of the heart valves will often showverrucae , or smallfriable lesions composed of bacteria, platelets and fibrin enmeshed together.Prognosis
Underlying structural valve disease is usually present in patients before developing subacute endocarditis, and the bacterial colonisation may cause the state of the valve to worsen. It is less likely to lead to septic emboli than is acute endocarditis, reducing the risk of septic infarcts and similar events. Subacute endocarditis has a relatively slow process of
infection and, if left untreated, can be present for a long time before the valves become completely incompetent. If left untreated it is always fatal.Treatment
The standard treatment is with a minimum of four weeks of high-dose intravenous
penicillin with anaminoglycoside such asgentamicin .The use of high-dose antibiotics are largely based upon animal models. [cite journal |author=Verhagen DW, Vedder AC, Speelman P, van der Meer JT |title=Antimicrobial treatment of infective endocarditis caused by viridans streptococci highly susceptible to penicillin: historic overview and future considerations |journal=J. Antimicrob. Chemother. |volume=57 |issue=5 |pages=819–24 |year=2006 |pmid=16549513 |doi=10.1093/jac/dkl087 |url=http://jac.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=16549513]
References
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