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What distinguishes endocarditis from other valvular diseases?
causes multisystemic disease- fever, lethargy, etc
What is the most common location and source of endocarditis in cattle?
- right-sided- tricuspid valve
- source- translocation of bacteria from liver/ GI tract important
What is the most common location of endocarditis in dogs and why?
left-sided valves- subvalvular aortic stenosis predisposes to aortic endocarditis
Endocarditis doesn't really occur in _________ [species].
What is a classic gross lesion assocaited with endocarditis?
vegetative- cauliflower valve leaflets
Describe the pathogenesis of bacterial endocarditis.
bacteremia--> bacteria adhere to valves (depending on virulence of microorganism)--> bacteria agglutinate and inoculate valve surface--> infection begins of surface facing normal blood flow--> vegetations form--> consist of bacterial colonies, thrombi, inflammatory cells, granulation tissue, fibrosis
Where on the valve does endocarditis begin?
on the surface FACING normal blood flow (ex. MV- atrial surface)
The first thing that happens to a valve with endocarditis is it starts to _______, so you hear....
leak; murmurs of insufficiency first (after healing attempts, you hear murmurs of stenosis)
What gross lesions appear with chronic endocarditis? (3)
contractions of lesions (fibrosis) and often calcification, jet lesions
Describe the microscopic pathologic findings with infective endocarditis. (3
- bacteria, platelets, fibrin, and inflammatory cells
- valvular destruction
- localized agranulocytosis (thrombin layers)
What kind of antimicrobial do you need to treat endocarditis and why?
- bactericidal drugs that can penetrate fibrin (agranulocytosis)
- fibrin isolates bacterial colonies from host defenses so bacteriostatic won't work (no immune cells get in to kill existing bacteria)
What is unique about Bartonella endocarditis?
aortic endocarditis in dogs, will culture negative on blood culture, have to use PCR or immunological methods to isolate
Describe the pathophysiology of how endocarditis causes multisystemic disease.
- infection of the valve—> shed bacteria—>predisposed to systemic inflammation and fever—> vegetations get big and friable—> break off—> emboli bland (no bacteria) or septic (bacteria)—> seed infection downstream—> body mounts immune reaction—> immune complexes form Ab-Ag—> filtered in kidney and joint—> immune mediated polyarthritis (common sign of infectious endocarditis) and glomerulonephritis
- Inflammation and thrombi- embolic pneumonia, lung abscesses, metastatic infections, vasculitis
What cardiac injuries can occur secondarily to infective endocarditis? (6)
valve injury, myocarditis, myocardial infarction, arrhythmias (secondary to inflammation), cardiomegaly from volume overload (valve leakage), CHF (chronic)
What are historical findings that predispose to infective endocarditis? (3)
prior or current infection, immunosuppressive drugs, shaking/shivering
What clinical findings are often associated with endocarditis? (9)
new heart murmur, hemorrhages/ thrombosis (vasculitis), tachycardia, hyperkinetic pulses, arrhythmia, signs of CHF, fever, polyarthritis, neurologic signs
What are potential causes of heart murmurs with endocarditis? (3)
regurg of leaky valves, functional ejection murmur due to fever, stenotic valves (if chronic)
Embolic pneumonia usually occurs in the _____________, just like ____________.
caudodorsal lung field; noncardiogenic edema
What lab findings are consistent with endocarditis? (6)
- CBC: anemia, leukocytosis (increased neuts or monos), thrombocytopenia (DIC), elevated plasma fibrinogen (LA)
- Chem: azotemia, increased globulins
What specific lab test are usually run to identify endocarditis and guide the antimicrobial plan?
- blood cultures (often neg, esp with Bartonella or if animal was recently on an atb)
- PCR (if culture negative)
With clinical findings __________ is confirmatory of endocarditis.
What echo findings can you use to diagnose endocarditis?
- thick, irregular, hyperechoic, valve leaflets may oscillate, scarring, SAM
- cardiac size and function used to prognosticate
What may cause you to suspect right-sided endocarditis? (6)
bovine, fever, lab signs (fibrinogen), murmur of TR, signs of pneumonia +/- R-CHF
What may cause you to suspect left-sided endocarditis? (4)
fever, lab signs of inflammation (leukocytosis, inc globulins), murmur of mitral or aortic regurg, polyarthritis
What triad of signs is VERY suggestive of endocarditis in a dog?
fever, polyarthritis, aortic regurgitation
What are the principals of therapy of endocarditis?
- antibiotic therapy based on cultures (if neg, based on common isolates for that species)- must be bactericidal and penetrate fibrin, IV initially, long term (6-8weeks)
- if evidence of thrombosis, aspirin or plavix
Why is the prognosis for endocarditis guarded to poor?
usually ends with heart failure, permanent valvular lesions always result
What is the "Duke Criteria" for diagnosing infectious endocarditis?
major + minor clinical signs, laboratory findings, and imaging findings= score for likelihood of IE