Infective Endocarditis

Question 1

Briefly describe the pathological process of endocarditis

Answer 1

Circulating organisms (usually bacteria) colonise the endocardium and damage a heart valve

Question 2

Which heart valves are most commonly affected in Endocarditis?

Answer 2

Mitral, aortic.

Question 3

List a possible sequel are to infective endocarditis

Answer 3

Infected septic emboli break off and flow to multiple organs.

Question 4

Where are these emboli likely to go and what are the consequences of this?

Answer 4

Kidneys are a likely site. Lodge in glomerular BM, cause protein leakage, attract compliment and neutrophils, punch holes in the BM and allow things like albumin through. Immune Ag-Ab complexes may also form.

Question 5

Is effective endocarditis more or less common in cats?

Answer 5

Less

Question 6

Is infective endocarditis common or uncommon?

Answer 6

Uncommon, life-threatening, usually fatal disease

Question 7

What are, breed and size dog does infective endocarditis often occur in?

Answer 7

Medium to large, mainly purebred, middle-aged, male dogs are predisposed.

Question 8

Is infective endocarditis associated with CVHD?

Answer 8

Not associated with this.

Question 9

What may be associated with Infective Endocarditis?

Answer 9

Congenital defects: SAS, PDA

Question 10

What is the most important prequisite for infective endocarditis to occur?

Answer 10

Blood-borne infection (usually bacteraemia)

Question 11

How is the valve surface infected?

Answer 11

Directly from blood flowing past in the lumen. Lesions are found downstream of disturbed flow.

Question 12

What do the lesions in infective endocarditis consist of?

Answer 12

Fibrin/platelet (first?) then infectious organisms.

Question 13

What are the 4 pathogens that are the most common Infective Endocarditis suspects?

Answer 13

Staph app.
Strep app.
E. Coli
P. Aeruginosa

Question 14

What pathogen causing infective endocarditis is a likely culprit in hard-to-diagnose, culture-negative cases

Answer 14

Bartonella

Question 15

Outline how vegetations for in Infective Endocarditis

Answer 15

Valve leaflet endothelium ulcerated, platelets adhere to sub-endothelial collagen, fibrin deposition, enlargement, vegetations form. Flimsy (friable) a first, calcified and fibrous later.

Question 16

What do the vegetations in Infective endocarditis do to the valves?

Answer 16

Cause valvular insufficiency, sometimes stenosis, sometimes both

Question 17

Does infective endocarditis happen faster or slower than CVHD?

Answer 17

A lot faster than in CVHD

Question 18

What is it important to know that Infective Endocarditis develops a lot faster than CVHD

Answer 18

Left-sided CHF can develop early.

Question 19

What structure may be damaged as a result of aortic valve involvement in infective endocarditis?

Answer 19

AV node

Question 20

What is one of the most prominent clinical features of Infective endocarditis regarding heart sounds?

Answer 20

New/changing heart murmur

Question 21

List 5 signs pointing towards infective endocarditis

Answer 21

Fever (may be variable) - 80-90% 
New/changing murmur
Lethargy, anorexia, weight loss, GI signs
Stiffness, lameness +/- joint swelling
A very unhappy, sick dog

Question 22

Aside from fever, murmur, joint issues, lethargy and a generally unhappy and sick dog, what are two other possible clinical signs? (Not seen in every case)

Answer 22

+/- signs of congestive heart failure

+/- syncope

Question 23

What difference in demeanour exists between CVHD and Infective endocarditis dogs?

Answer 23

A very unhappy, sick dog (infective endocarditis cases)

Question 24

In one sentence, what is a major clinical sign you might expect when diagnosing an animal with infective endocarditis

Answer 24

Fever and a new murmur in an unhappy, sick dog

Question 25

Why is diagnosis of Infective Endocarditis difficult?

Answer 25

Fever of any cause can cause or exacerbate a pre-existing heart murmur. A new murmur may have just use been missed up until now, or may be the beginning of something else.

Question 26

Why is a DIASTOLIC MURMUR at the heart base in an unhappy dog with a fever strong evidence for aortic valve endocarditis

Answer 26

The valve us insufficient - backward flow during diastole from IgM pressure aorta to low pressure ventricular outflow tract

Question 27

On echocardiography, what is strong evidence of infective endocarditis

Answer 27

Flopping vegetations or valve destruction.

Question 28

List 2 definitive or strongly evident diagnostic tests confirming your shithouse diagnosis of infective endocarditis

Answer 28

Echocardiographic evidence of flopping vegetations or valve destruction.
Two or more positive blood cultures.

Question 29

Outline how you would go about getting a sample for blood culture

Answer 29

Collect a large volume >10mL for each sample
Sterile venipuncture
Do repeatedly from different veins, no more than an hour apart
Blood goes into special bottle (vented prior to blood addition), aerobic, prolonged incubation may be needed.

Question 30

How do we treat infective endocarditis?

Answer 30

Aggressive therapy with bactericidial antibiotics capable of penetrating fibrin. Supportive care

Question 31

List some antibiotics (or antibiotic combinations) we may use to treat infective endocarditis

Answer 31

B-lactam + aminoglycoside

OR a fluorquinolone

Question 32

Prognosis for infective endocarditis cases?

Answer 32

Guarded to poor, long-term