Bacterial endocarditis

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Endocarditis is defined at "Exudative and proliferative inflammatory alterations of the endocardium, characterized by the presence of vegetations on the surface of the endocardium or in the endocardium itself, and most commonly involving a heart valve, but sometimes affecting the inner lining of the cardiac chambers or the endocardium elsewhere. It may occur as a primary disorder or as a complication of or in association with another disease".[1]

Diagnosis

In general, a patient should fulfill the Duke Criteria[2] in order to establish the diagnosis of endocarditis.

As the Duke Criteria relies heavily on the results of echocardiography, research has addressed when to order an echocardiogram by using signs and symptoms to predict occult endocarditis among patients with intravenous drug abuse[3][4][5] and among non drug-abusing patients [6][7]. Unfortunately, this research is over 20 years old and it is possible that changes in the epidemiology of endocarditis and bacteria such as staphylococcus make the following estimates incorrectly low.

Among patients who do not use illicit drugs and have a fever in the emergency room, there is a less than 5% chance of occult endocarditis. Mellors [7] in 1987 found no cases of endocarditis nor of staphylococcal bacteremia among 135 febrile patients in the emergency room. The upper confidence interval for 0% of 135 is 5%, so for statistical reasons alone, there is up to a 5% chance of endocarditis among these patients. In contrast, Leibovici [6] found that among 113 non-selected adults admitted to the hospital because of fever there were two cases (1.8% with 95%CI: 0% to 7%) of endocarditis.

Among patients who do use illicit drugs and have a fever in the emergency room, there is about a 10% to 15% prevalence of endocarditis. This estimate is not substantially changed by whether the doctor believes the patient has a trivial explanation for their fever[5]. Weisse[3] found that 13% of 121 patients had endocarditis. Marantz [5] also found a prevalence of endocarditis of 13% among such patients in the emergency room with fever. Samet [4] found a 6% incidence among 283 such patients, but after excluding patients with initially apparent major illness to explain the fever (including 11 cases of manifest endocarditis), there was a 7% prevalence of endocarditis.

Among patients with staphylococcal bacteremia (SAB), one study found a 29% prevalence of endocarditis in community-acquired SAB versus 5% in nosocomial SAB[8]. However, only 2% of strains were resistant to methicillin and so these numbers may be low in areas of higher resistance.

Echocardiography
The transthoracic echocardiogram has a sensitivity and specificity of approximately 65% and 95% if the echocardiographer believes there is 'probabable' or 'almost certain' evidence of endocarditis[9][10].

Prevention

According to clinical practice guidelines from the American Heart Association, the following patients are "Highest Risk of Adverse Outcome From Endocarditis for Which Prophylaxis With Dental Procedures Is Reasonable" if they are undergoing "dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa":[11]

  • "Prosthetic cardiac valve or prosthetic material used for cardiac valve repair"
  • "Previous IE [infective endocarditis]"
  • "Congenital heart disease (CHD)*"
    • "Unrepaired cyanotic CHD, including palliative shunts and conduits"
    • "Completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or by catheter intervention, during the first 6 months after the procedure"
    • "Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (which inhibit endothelialization)"
  • Cardiac transplantation recipients who develop cardiac valvulopathy

References

  1. ↑ National Library of Medicine. Endocarditis. Retrieved on 2007-10-19.
  2. ↑ Durack D, Lukes A, Bright D (1994). "New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Duke Endocarditis Service.". Am J Med 96 (3): 200-9. PMID 8154507.
  3. ↑ 3.0 3.1 Weisse A, Heller D, Schimenti R, Montgomery R, Kapila R (1993). "The febrile parenteral drug user: a prospective study in 121 patients.". Am J Med 94 (3): 274-80. PMID 8452151. Cite error: Invalid <ref> tag; name "Weisse" defined multiple times with different content
  4. ↑ 4.0 4.1 Samet J, Shevitz A, Fowle J, Singer D (1990). "Hospitalization decision in febrile intravenous drug users.". Am J Med 89 (1): 53-7. PMID 2368794. Cite error: Invalid <ref> tag; name "Samet" defined multiple times with different content
  5. ↑ 5.0 5.1 5.2 Marantz P, Linzer M, Feiner C, Feinstein S, Kozin A, Friedland G (1987). "Inability to predict diagnosis in febrile intravenous drug abusers.". Ann Intern Med 106 (6): 823-8. PMID 3579068. Cite error: Invalid <ref> tag; name "Marantz" defined multiple times with different content Cite error: Invalid <ref> tag; name "Marantz" defined multiple times with different content
  6. ↑ 6.0 6.1 Leibovici L, Cohen O, Wysenbeek A (1990). "Occult bacterial infection in adults with unexplained fever. Validation of a diagnostic index.". Arch Intern Med 150 (6): 1270-2. PMID 2353860. Cite error: Invalid <ref> tag; name "Leibovici" defined multiple times with different content
  7. ↑ 7.0 7.1 Mellors J, Horwitz R, Harvey M, Horwitz S (1987). "A simple index to identify occult bacterial infection in adults with acute unexplained fever.". Arch Intern Med 147 (4): 666-71. PMID 3827454. Cite error: Invalid <ref> tag; name "Mellors" defined multiple times with different content
  8. ↑ Kaech C, Elzi L, Sendi P, Frei R, Laifer G, Bassetti S, Fluckiger U (2006). "Course and outcome of Staphylococcus aureus bacteraemia: a retrospective analysis of 308 episodes in a Swiss tertiary-care centre.". Clin Microbiol Infect 12 (4): 345-52. DOI:10.1111/j.1469-0691.2005.01359.x. PMID 16524411. Research Blogging.
  9. ↑ Shively B, Gurule F, Roldan C, Leggett J, Schiller N (1991). "Diagnostic value of transesophageal compared with transthoracic echocardiography in infective endocarditis.". J Am Coll Cardiol 18 (2): 391-7. PMID 1856406.
  10. ↑ Erbel R, Rohmann S, Drexler M, Mohr-Kahaly S, Gerharz C, Iversen S, Oelert H, Meyer J (1988). "Improved diagnostic value of echocardiography in patients with infective endocarditis by transoesophageal approach. A prospective study.". Eur Heart J 9 (1): 43-53. PMID 3345769.
  11. ↑ Wilson W, Taubert KA, Gewitz M, et al (2007). "Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group". Circulation 116 (15): 1736–54. DOI:10.1161/CIRCULATIONAHA.106.183095. PMID 17446442. Research Blogging.
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