Endocarditis

Question 1

What are some signs / symptoms of endocarditis

Answer 1

fever and lethargy for the past few weeks

On examination: fever, splinter haemorrhages and an early diastolic murmur

Question 2

Endocarditis pathogenesis

Answer 2

Turbulent flow through ABNORMAL valve, due to congenital abnormality, nodules from rheumatic heart disease etc
Platelets and fibrin attach to damaged valvular epithelium forming sterile vegetations
Transient bactereamia arising from mouth, skin, gut, urinary tract etc. seeds bacteria onto sterile vegetations
Infected vegetation enlarges and sheds infected emboli and leads to valvular destruction

Question 3

What are the mouth bacteria that cause endocarditis?

Answer 3

Viridians Streptococci

Question 4

What are the nose/skin bacteria that cause endocarditis

Answer 4

Staph aureus

Question 5

what are the gut/urinary tract bacteria that cause endocarditis?

Answer 5

Enterococcus faecalis

Question 6

How can you die from endocarditis?

Answer 6

Either:
- Impaired valve function causing heart failure
OR
- Emboli causing infarcts

Question 7

Cure?

Answer 7

0% chance by host defences
100% mortality without effective treatment
Heart valves are avascular, so neutrophils can’t be delivered to them through capillaries and the blood flowing past the valves in the heart is flowing at a speed that doesn’t allow the neutrophils to stick

Question 8

Diagnostic methods?

Answer 8

Document CONTINUOUS bacteremia
- expect all blood cultures to be positive (with organism likely to cause endocarditis)
Culture blood on 3 occasions at least 20min apart
and possibly culture excised valve
oranges identified in about 95% of cases
*even of you’re dying from a bacterial infection e.g. pneumonia, could still take samples of blood that WONT show a bacteria culture

Question 9

What is bacteremia?

Answer 9

bacteria cultured from blood sample

Question 10

True bacteremeia

Answer 10

pathogen cultures
sometimes more than one set of cultures positive
clinically compatible infective source identified

Question 11

Contaminant bacteremia

Answer 11

Skin contaminant cultured
Only one set of blood cultures positive
No apparent infective source

Question 12

Transient bacteremia

Answer 12

gut or mouth organism cultured
Blood cultures only positive briefly
No apparent infective source

Question 13

Treatment

Answer 13

bactericidal treatment for weeks, antibiotic dependant on organism 
Always through IV 
Always high dose 
2-4 weeks 
Cure rate 70-90%

Question 14

Endocarditis microbial etiology

Answer 14

mainly caused by viridians streptococci (alpha haemolytic)

this is a usually harmless bacteria that resides in the mouth but sticks to heart valves

Question 15

Rheumatic fever and endocarditis the sources of confusion

Answer 15

RF

• Strep. pyogenes only
• Pharyngitis
• Immunologic damage to valves
• Nodules on valves
• Treatment with oral penicillin for 10 days
• Prophylaxis with IM penicillin for many years

ECD

• Viridans strep and others
• mouth commensals
• Infection of valves
• Vegetations on valves
• Treatment with IV penicillin for one month
• Prophylaxis with oral penicillin when dental work operating