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Infective Endocarditis: Difference between revisions
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''Author: A. Crystal'' | |||
==Introduction== | ==Introduction== | ||
Infective endocarditis (IE) is an infectious and inflammatory process of endothelial lining of the heart structures and valves. It is most commonly caused by bacterial and fungal infections, although non-infective causes of endocarditis occur, this chapter will concentrate on infective causes. | Infective endocarditis (IE) is an infectious and inflammatory process of endothelial lining of the heart structures and valves. It is most commonly caused by bacterial and fungal infections, although non-infective causes of endocarditis occur, this chapter will concentrate on infective causes. | ||
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==Pathogenesis and Causes== | ==Pathogenesis and Causes== | ||
[[Image:Heart1.JPG|thumb|300px|Large lesions on non coronary and left coronary cusps normal valves otherwise]] | |||
[[Image:Heart2.JPG|thumb|300px|Vegetations on tricuspid valve]] | |||
[[Image:Heart3.JPG|thumb|300px|Septic emboli to the conjunctiva]] | |||
Generally, endothelial damage to heart valves predisposes to bacterial infections as it is generally resistant to bacterial infections. This may be caused by turbulent blood flow in damaged valves, septal defects or instrumentation. Although, recent evidence suggests that A-type von Willebrand factor may contribute to S. aureus binding in endothelial intact valves<cite>v</cite>. Specifically, in patients with S. aureus bacteremia, native valve endocarditis was reported to be in 19% of patients, and 38% in those with prosthetic valves<cite>vi</cite>. | Generally, endothelial damage to heart valves predisposes to bacterial infections as it is generally resistant to bacterial infections. This may be caused by turbulent blood flow in damaged valves, septal defects or instrumentation. Although, recent evidence suggests that A-type von Willebrand factor may contribute to S. aureus binding in endothelial intact valves<cite>v</cite>. Specifically, in patients with S. aureus bacteremia, native valve endocarditis was reported to be in 19% of patients, and 38% in those with prosthetic valves<cite>vi</cite>. | ||
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Gram negative bacilli IE is rather uncommon, the HACEK organisms (Haemophillus spp, Actinobacillus, Cardiobacterium hominis, Eikenella corrodens, Kingella spp) are responsible for approximately 3% of endocarditis cases and are the most common cause for gram negative endocarditis in non-intravenous drug users<cite>xi</cite>. Non-HACEK organisms are a rare cause for endocarditis and only account for <1-2% of causes. | Gram negative bacilli IE is rather uncommon, the HACEK organisms (Haemophillus spp, Actinobacillus, Cardiobacterium hominis, Eikenella corrodens, Kingella spp) are responsible for approximately 3% of endocarditis cases and are the most common cause for gram negative endocarditis in non-intravenous drug users<cite>xi</cite>. Non-HACEK organisms are a rare cause for endocarditis and only account for <1-2% of causes. | ||
Fungal endocarditis occurs in patients who receive prolonged parenteral nutrition or antibiotics through intravenous catheters. It has also been described in intravenous drug users. Patients are often immunocompromised. The most common organisms implicated are Candida species, Histoplasma capsulatum, and Aspergillus. Mortality rates associated with fungal endocarditis exceed 80%<cite>xii</cite>. | Fungal endocarditis occurs in patients who receive prolonged parenteral nutrition or antibiotics through intravenous catheters. It has also been described in intravenous drug users. Patients are often immunocompromised. The most common organisms implicated are Candida species, Histoplasma capsulatum, and Aspergillus. Mortality rates associated with fungal endocarditis exceed 80%<cite>xii</cite>. | ||
==Diagnosis== | ==Diagnosis== | ||
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The sensitivity of detecting on echocardiogram varies. Transthoracic and transesophageal echocardiogram sensitivities for detecting vegetations are 50% and 90% respectively.<cite>xiv</cite><cite>xv</cite> | The sensitivity of detecting on echocardiogram varies. Transthoracic and transesophageal echocardiogram sensitivities for detecting vegetations are 50% and 90% respectively.<cite>xiv</cite><cite>xv</cite> | ||
{| class="wikitable" cellpadding="0" cellspacing="0" border="0" width=" | {| class="wikitable" cellpadding="0" cellspacing="0" border="0" width="500px" | ||
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!colspan="2"|Endocarditis of prosthetic mitral valve | !colspan="2"|Endocarditis of prosthetic mitral valve | ||
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[[Image:Heart4.JPG|thumb|300px|Roth Spots]] | |||
==Therapy== | ==Therapy== | ||
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In cases of prosthetic valve endocarditis (PVE), microbiological activity depends on early (<2 months post op) or late (>2 months post op). In early PVE S.aureus accounts for 40% of the cases, followed by coagulase negative staphylococcus (17%). In late PVE coagulase negative staphylococcus accounts for 20% of cases, followed by S. aureus (18%). Coverage for enterococci, streptococci, and gram negative should be considered in empiric therapy in both groups. Rifampin + Vancomycin + Gentamicin should be initiated for PVE <12 post op. Suspected PVE >12 months post op may be treated with the same regimen as for native valves.<cite>xvi</cite> | In cases of prosthetic valve endocarditis (PVE), microbiological activity depends on early (<2 months post op) or late (>2 months post op). In early PVE S.aureus accounts for 40% of the cases, followed by coagulase negative staphylococcus (17%). In late PVE coagulase negative staphylococcus accounts for 20% of cases, followed by S. aureus (18%). Coverage for enterococci, streptococci, and gram negative should be considered in empiric therapy in both groups. Rifampin + Vancomycin + Gentamicin should be initiated for PVE <12 post op. Suspected PVE >12 months post op may be treated with the same regimen as for native valves.<cite>xvi</cite> | ||
[http://circ.ahajournals.org/content/111/23/3167.full | The American Heart Association recommendation for specific antimicrobial therapy can be found in their [http://circ.ahajournals.org/content/111/23/3167.full guideline]. | ||
[http://eurheartj.oxfordjournals.org/content/30/19/2369.long | The European Society of Cardiology [http://eurheartj.oxfordjournals.org/content/30/19/2369.long guideline for the treatment of Infective endocarditis.] | ||
===Prophylaxis=== | ===Prophylaxis=== | ||
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==References== | ==References== | ||
<biblio> | <biblio> | ||
#i | #i [http://www.nejm.org/doi/full/10.1056/NEJMcp1206782 "Infective Endocarditis - N Engl J Med 2013." 12 Sep. 2013] | ||
#ii Cabell CH, Fowler VG, Jr, Engemann JJ, et al. Endocarditis in the elderly: Incidence, surgery, and survival in 16,921 patients over 12 years. Circulation.2002;106(19):547. | #ii Cabell CH, Fowler VG, Jr, Engemann JJ, et al. "Endocarditis in the elderly: Incidence, surgery, and survival in 16,921 patients over 12 years." Circulation.2002;106(19):547. | ||
#iii | #iii pmid=12092473 | ||
#iv | #iv pmid=22870738 | ||
#v pmid=23720451 | #v pmid=23720451 | ||
#vi pmid=21685200 | #vi pmid=21685200 | ||