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Endocarditis: defn

Microbial infection of heart valves or endocardium.

2 Types of bacterial Endocarditis

1. Subacute bacterial endocarditis (SBE):
-Insidious onset
-Symptoms prior to Dx: weeks-months
-Preexisting damaged valve
-viridans streptococci
2. Acute bacterial endocarditis:
-Acute onset- less than 5 weeks
-Normal valve often
-Staphylococcus aureus

Pathogenesis of Endocarditis (4 things that need to happen to develop endocarditis)

1. Hemodynamic change
2. Platelet-fibrin thrombi
3. Bacteremia
4. Adherence

1. Hemodynamic change

Anatomical alteration within the heart results in blood going from high pressure zone into low pressure sink.
eg. Mitral regurgitation; VSD, but not ASD

2. Platelet-fibrin thrombi

"Vegetations" made up of sterile platelet-fibrin thrombi form when hemodynamic change causes trauma to the endothelial surface and exposes collagen.

3. Bacteremia

Bacteria need to enter the bloodstream to get to the damaged heart valves.
-on a daily basis we do things that put bacteria from mucous membranes to blood stream (eg: brushing teeth) and IV drug users inject non-sterile things directly into their bloodstream (hence acute)

4. Adherence

The bugs have to stick.
-not every bacteria will cause endocarditis because not all have the ability to stick
-bacteria that stick:
enterococcous, staph aureus, staph epidermidis, viridans streptococcus, pseudomonas

Predisposing heart disease

1. Mitral prolapse with MR * most common
2. Rheumatic (MR, AR, AS)
3. Atherosclerotic
4. Congenital (VSD, bicuspid AV)
5. Prosthetic valves
6. A-V shunts
7. Trauma from central catheter

Bacteria that cause endocarditis (by order of prevalence)

1. Staphylococci (most aureus): 30-40%; 1/3 of these due to central catheters
2. Streptococci (most viridans): 20-30%
3. Enterococci: 10%
4. Gram Neg: 2% + Fungi: 2%
5. Culture Neg: 10%; can be due to prescribing antibiotic for wrong reason or organisms difficult to grow, but #1 reason is Bartonella

Culture Negative Endocarditis

1. Prior antimicrobials (prescribing antibiotics for wrong reason)
2. Hard to grow/fastidious bugs:
-Bartonella**, H.A.C.E.K, Brucella, nutritionally variant streptococci, Legionella, mycobacteria
3. Fungi
4. Coxiella, Chlamydia
5. Non-infective endocarditis (SLE, marantic)

Special Cases: IV drug users and Prosthetic valves.

1. IV drug users: staph aureus
2. Prosthetic valves: staph epidermidis

Clinical Picture

1. Infection
2. Heart
3. Emboli
4. Immune complexes
-infection is in the intravascular space so immune complexes can form

Clinical Picture:
1. Infection

1. Fever
2. Chills, sweats
3. Leukocytosis
4. Elevated sedimentation rate
-rate that RBCs drop (norm 20 mm/hr)
-in endocarditis can be 100 mm/hr due to fibrinogen that attaches to RBCs and causes them to clump and fall faster
5. Anemia
-anemia of chronic disease
6. splenomegaly

Clinical Picture:
2. Heart

1. Murmur
2. Heart failure
3. Heart block

Clinical Picture:
3. Emboli

1. Stroke
2. Skin lesions
3. Hematuria
4. Metastatic infections
5. Spleen infarction
6. Cavitary lung nodules (tricuspid valve)

Clinical Picture:
4. Immune complexes

1. Arthritis
2. Glomerulonephritis (hematuria)
3. Vasculitis
-petechiae, Roth spot (retinal hemorrhages with clear center), Osler's node (raised, tender lesions on fingers/toes), Janeway lesions (non-raised, tender lesions on fingers/toes)
4. Rheumatoid factor
5. Decreased complement

When to think of endocarditis

1. Fever and a murmur
2. Fever and IV drug use
3. Fever of unexplained origin (FUO): fever>3wks
4. Fever and systemic emboli (stroke)
5. Fever after valve surgery

Diagnosis of endocarditis

1. Clinical picture
2. Blood cultures: 3 separate sticks at least 20 mins apart
4. Echocardiography
-Transthoracic vs. transesophageal
5. "Duke criteria"

Treatment of endocarditis

1. Bactericidal drugs: bc bacteria are within platelet-fibrin complexes
-synergy: penicillin + gentamicin
2. High doses
3. Long time

Note: there are 3 times you NEED to use bactericidal drugs over bacteriostatic drugs: endocarditis, meningitis, patients with low WBC count

Major indication for surgery on NATIVE heart valves

intractable heart failure

the other indicated time to do surgery is if the patient has an artificial valve infection. the infection is around the sutures when prosthetic valves get infected, therefore they need to be taken out.

Endocarditis prophylaxis

1. Give antibiotics to those at high risk for endocarditis at time of procedures likely to be attended by bacteremia.
2. Directed at endocarditis etiologies.
3. Standard of care.
4. No proof of efficacy.
5. Even if worked wouldn't prevent most cases.

Prophylaxis= penicillin (if allergy, clindamycin)

Who should get prophylaxis?

Only those with cardiac conditions associated with the highest risk of adverse outcome from endocarditis:
1. Prosthetic cardiac valve
2. Previous endocarditis
3. Congenital heart disease (only those listed here):
-Unrepaired cyanotic CHD, including palliative shunts and conduits.
-Completely repaired CHD with prosthetic material or device, whether placed by surgery or by catheter, during the first 6 months after the procedure.
-Repaired CHD with residual defects at or adjacent to prosthetic patch or device.
4. Cardiac transplantation recipients who develop valvulopathy.

What procedures should get it?

All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa.*

*Not for routine anesthetic injections, taking dental radiographs, placement of orthodontic brackets, shedding of deciduous teeth, and bleeding from trauma to lips or oral mucosa.

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