Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Infective Endocarditis: Role of Transthoracic Versus Transesophageal Echocardiography


Acknowledgments

The authors gratefully acknowledge Susan Nord and Jennifer Pfaff for their editorial assistance and Brian Miller and Brian Schurrer for their help with the figures. We also thank Drs. Maria C. Todaro, Concetta Zito, and Scipione Carerj for their contributions to the previous edition of this chapter.

Infective endocarditis (IE) is one of the most severe infectious diseases and is characterized by a poor prognosis and high mortality rates and associated with prolonged hospitalization and a high risk of need for surgery. The incidence of IE ranges among countries from 3 to 10 episodes per 100,000 person years and increases dramatically with age, reaching a peak incidence of 14.5 episodes per 100,000 person years in patients aged 70 to 80 years.

Since its first description in 1885, the epidemiology of the disease has greatly changed. In the most developed countries, the increasing and widespread incidence of diabetes, chronic kidney failure requiring hemodialysis, and intravascular devices associated with progress in cardiac valve repair or replacement techniques have generated a new microbiological profile of IE, with a prevalence of infections caused by staphylococci, enterococci, fungi, and other resistant health care–related agents typically involving older patients with prosthetic valves or degenerative valve disease. In contrast, developing countries are characterized by a prevalence of streptococcal infections and culture-negative IE affecting patients of younger age at presentation and higher incidence of structural cardiac predisposing risk factors such as rheumatic disease and untreated congenital heart disease. ,

According to the site of infection and the presence of intracardiac materials, endocarditis can be classified as left-sided native valve IE, left-sided prosthetic valve IE, right-sided IE, or device-related IE (on pacemaker or defibrillator wires with or without associated valve involvement). This differentiation is important because the pathophysiology and diagnostic strategy of the different subtypes of endocarditis are different.

The diagnosis of IE is based on the clinical picture, echocardiographic findings, and microbiological diagnosis. The Duke criteria and the modified Duke criteria provide high sensitivity and specificity for diagnosis ( Table 114.1 ). , IE can present acutely with septic changes and rapidly progressive infection but also as a subacute or chronic disease with a low-grade fever and nonspecific symptoms, which may delay the diagnosis, especially when occurring in patients with no previous history of valve disease. A range of other conditions, including rheumatic disease, chronic infection, malignancy, and autoimmune disease, can be suspected before the diagnosis of IE is established.

TABLE 114.1
Modified Duke Criteria for the Diagnosis of Infective Endocarditis
Adapted from Li JS, et al: Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis, Clin Infect Dis 30:633–638, 2000.
Major Criteria
Blood Cultures Positive for IE
Typical microorganisms consistent with IE from two separate blood cultures:

  • Viridans streptococci, Streptococcus bovis , HACEK group, Staphylococcus aureus or community-acquired enterococci in the absence of a primary focus

  • Or microorganisms consistent with IE from persistently positive blood cultures: at least two positive cultures of blood samples drawn >12 hours apart

  • Or All of three or a majority of four or more separate cultures of blood (with first and last sample drawn at least 1 hour apart)

  • Or single positive blood culture for Coxiella burnetii or phase I IgG antibody titer >1:800

Evidence of Endocardial Involvement

  • Echocardiography positive for IE: vegetation, abscess, new partial dehiscence of prosthetic valve

  • New valvular regurgitation

Minor Criteria

  • Predisposition: predisposing heart condition, injection drug use

  • Fever: temperature >38°C

  • Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhages, conjunctival hemorrhages, Janeway lesions

  • Immunologic phenomena: glomerulonephritis, Osler nodes, Roth spots, rheumatoid factor

  • Microbiological evidence: positive blood culture but does not meet a major criterion or serologic evidence of active infection with organism consistent with IE

Diagnosis of IE is definite in the presence of:

  • Two major criteria

  • Or one major and three minor criteria

  • Or five minor criteria

Diagnosis of IE is possible in the presence of:

  • One major and one minor criterion

  • Or three minor criteria

HACEK, Haemophilus spp., Aggregatibacter spp., Cardiobacterium hominis, Eikenella corrodens, and Kingella spp.; IE, infective endocarditis.

In IE caused by virulent organisms such as Staphylococcus aureus , the diagnosis can be missed when extracardiac signs of infection predominate and the clinical signs of valve disease are initially absent or difficult to evaluate ( , ). It is necessary to consider the diagnosis of IE in all cases of sepsis, particularly in all patients presenting with fever of unclear origin and an embolic episode even if there is no previous history of cardiac disease.

Video 114.1. Example of Staphylococcus aureus endocarditis affecting the aortic valve. Transesophageal echocardiography shows vegetations and a torn leaflet.

Video 114.2. Example of Staphylococcus aureus endocarditis affecting the aortic valve. Real-time two-dimensional echocardiography shows vegetations and a torn leaflet.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts