-
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].
cats
-
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.
echocardigraphy
-
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
|
|