Infective Endocarditis Flashcards
The analogous process involvingarteriovenous shunts, arterio-arterial shunts (patent ductus arteriosus),or a coarctation of the aorta is called
infective endarteritis
is a hectically febrile illness that rapidly damages cardiac structures, seeds extracardiac sites, and, if untreated, progresses to death within weeks.
Acute endocarditis
follows an indolent course;
causes structural cardiac damage only slowly, if at all; rarely metastasizes; and is gradually progressive unless complicated by a major embolic event or a ruptured mycotic aneurysm
Subacute endocarditis
The risk of PVE is greatest during the first____ after valve replacement; gradually declines to a low, stable-rate thereafter; and is similar for mechanical and bioprosthetic devices.
6–12 months
Injection drug use–associated endocarditis, especially that involving the tricuspid valve, is commonly caused by____ which in manycases is resistant to methicillin. Left-sided valve infections in addictshave a more varied etiology
S. aureus,
PVE arising within 2 months of valve surgery—i.e., early PVE—is generally nosocomial and is the result of intraoperative contamination of the prosthesis or a bacteremic postoperative complication. This nosocomial origin is reflected in the primary microbial causes:
S. aureus CoNS (coagulase-negativestaphylococci) facultative gram-negative bacilli diphtheroids and fungi
TRue or false
HIV infection in drugusers does not significantly influence the causes of endocarditis.
True
Endothelial injury (e.g., at the site of impact of high-velocity blood jets or on the low-pressure side of a cardiac structural lesion) allows either direct infection by virulent organisms or the development of a platelet–fibrin thrombus—a condition called
nonbacterial thrombotic endocarditis (NBTE)
nonbacterial thrombotic endocarditis (NBTE)
also arises as a result of a hypercoagulable state;
this phenomenon gives rise to____ (uninfected vegetations seen in patients with malignancy and chronic diseases) and to bland vegetations complicating systemic lupus erythematosus and antiphospholipid antibody syndrome.
marantic endocarditis
The classic nonsuppurative peripheral manifestations of SUBACUTE endocarditis are related to prolonged infection; with early diagnosisand treatment, these have become infrequent.
Janeway lesions
In contrast, septic embolization mimicking some of these lesions is common in patients with ACUTE S. aureus endocarditis
subungual hemorrhage
Osler’s nodes
are focal dilations of arteries occurring at points in the artery wall that have been weakened by infection in the vasa vasorum or where septic emboli have lodged
Mycotic aneurysms
Almost 50% of endocarditis associated with injection drug use is limited to the ____ valve and presents with fever but with faint or nomurmur and no peripheral manifestations.
tricuspid
Blood cultures:
In patients with suspected NVE, PVE, or CIED endocarditis who have not received antibiotics during the prior 2 weeks
three 2-bottle blood culture sets, separated from one another by at least 2 h, should be obtained from different venipuncture sites over 24 h.
What Single positive blood culture is a major criterion for IE
Coxiella burnetii or
phase I IgG antibodytiter of >1:800
is the optimal method for the diagnosis of PVE andCIED endocarditis as well as for the detection of myocardial abscess,valve perforations, or intracardiac fistulae
TEE
Use for E. faecalis isolates with or without high-levelresistance to gentamicin and streptomycin or for patientsat high risk for aminoglycoside nephrotoxicity (creatinineclearance rate <50 mL/min; see text).
Ampicillin (2 g IV q4h) plus ceftriaxone (2 g IV q12h) both for 6 weeks
is the major indication for cardiac surgery
Moderate to severe refractory CHF caused by new or worsening valve dysfunction or intracardiac fistulae
This complication, is the most common Perivalvular Infection and occurs in 10–15% of patients with NVE and in 45–60% of those with PVE.
aortic valve infection
is the test of choice to detect perivalvular abscesses(sensitivity, ≥85%).
TEE with color Doppler
Surgical treatment is also advised for endocarditis caused by organisms against which effective antimicrobial therapy is lacking (e.g.,
yeasts
fungi
P. aeruginosa
other highly antibiotic-resistant bacteria,Brucella species).
True or false:
Surgical treatment should be considered for patients with MRSA left-sided NVE who remain septic and unresponsive to alternative antibiotics.
True
True or false
Isolated tricuspid-valve S. aureus endocarditis, even with persistent fever, rarely requires surgery.
True