Infective endocarditis usually preceeded by predisposing cardiac lesion.
Congenital heart disease (bicuspid aorta, VSD, coarctation of aorta, Tetralogy of Fallot).
Cardiac conditions (such as aortic stenosis) create flow abnormalities - venturi effect.
The gerater the pressure gradient, the higher the risk.
Pressure gradient creates post-stenotic pressure drop (venturi effect, like water going past opening beween the rocks... see pooling of debris downstream).
Vegetations form on downstream of low-pressure side of valve lesion.
Aortic stenosis --> vegetations on aortic coronary cusp.
Mitral regurg --> atrial vegetations.
Tricuspid regurg --> rare (only IV drug users).
Bacteria enter the endocardium --> induce platelet aggregation --> platelet-fibrin complex--> protective environment for bacteria (WBC cannot enter).
Alternate from biologically active to dormat phase.
Prosthetic valves serve as perfect sites for bacterial adherence.
Strep express dextran to adhere to tooth enamel. (cause dental carries).
#1 cause of bacterial endocarditis.
S. mutans and S. sanguis most commonly cause endocarditis.
Enters bloodstream via GI tract - colonic carcinoma portal.
Haemophius aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae.
Fungi (C. albicans - IV drugs and prosthetic valves).
Mucosal surface damage --> transient bacteremia.
Dental extractions, periodontal surgery, gum chewing, tooth brushing.
Non-specific symptoms begin 2 weeks after bacteremia.
Often takes 5 weeks to diagnose.
Low-grade fever ~38, maybe chills (night sweats uncommon).
Fatigue, anorexia, weakness, malaise, weight loss.
Commonly associated with S.aureus, enterococci, and occasionally S. pneumo.
Rapid diagnosis needed to decrease valvular destruction and embolic complications!!!
Heart murmur (almost always) - often unchanging (unless leaflet destroyed w/ S. aureus) or chordae tendinae rupture.
New aortic regurg murmur = bad sign. ---> CHF develops.
If vegetation large enough can cause aortic stenosis!
Fundoscopy = Roth spots, retinal hemorrhages.
Petechiae on bucchal mucosa, palate, extremities.
Check pads of fingers, toes, and thenar eminence.
Janeway lesions (S. aureus infection).
If neuro symptoms (CT /MRI head).
No contarct --> embolic infarction, intracerebral hemorrhage, brain abscess.
Blood cultures (do X2 preferrably 20min apart !!!!) and then once again before starting abx.
If elevated WBC count --> myocardial abscess?
Mimic connective tissue disorders b/c vegetation seeds bacterial chronically.
ECG --> watch for conduction defect (infection spread to conduction system).
Endocarditis --> constant low-level bactermia.
Sensitivity: 85-95% on first culture, and 95-100% on second.
Third blood culture documents constancy of bactermia.
Trans-Thoracic Echo TTE (sens 44-63%) for detecting vegeations.
Definitive diagnosis of infective endocarditis in absence of valve tissue pathology is difficult.
Echocardiographic minor criteria --> removed from minor.
Need cidal antibiotics b/c bacterial in fibrin cannot be accessed by neutrophils.
Aminoglycoside: Synergy in killing (I guess stops B-lactamase production).
PenG OR amp+gent are first line.
Ceftriaxone + gent + vanco 2nd line.
Often not curative alone (esp if prosthetic valve). Surgical prosthetic valve replacement or debridement of valve improves survival.
1. Moderate-to-severe CHF (most frequent indication) Death can be sudden.
Regurgitation (leaflet destruction), stenosis, Perivalvular extension. Conduction problems.
Embolic Strokes, Intra-cerebral hemorrhage, encephalopathy, meningitis, meningoencephalitis, brain abscess.
High in elderly and thrombocytopenia.
R-sided endocarditis (IV drug use) --> pulmonary emboli or abscesses.
Infectious emboli lodged in arterial bifurcations (occlude vasa vasorum of vessel lumen --> damage of musclar layer --> aneurism--> risk of rupture).
The following are indications for dental procedures involving gingival manipulation.
Cardiac valvulopathy in cardiac transplant recipients.
Give as single dose 30-60min before the procedure.