Lecture 22 - Endocarditis

Question 1

Endocarditis - symptoms

Answer 1

• fever, lethargy for past 2 weeks
• on examination has fever, splinter haemorrhages, early diastolic murmur , conjunctival haemorrhages
• small clot in nail bed leading to damage of that arteriol and leakage of blood
• also can have this in the conjuntiva

Question 2

What happens

Answer 2

• get infection of the value - either aortic valve or mitral valve usually
• normally due to infection of a bacterial species on the valve
• leads to clumps of fibrin and platelets growing on the surface of valve to produce vegetations
• these bits break off and travel in the arterial blood supply and end up where it get deliverd - fingers, toes ect.
• these can block arteries - can get death e.g stroke
• can also lead to damage of valve
• if the damage extends down to chorda tempini, then can get regurgitation, and heart failure

Question 3

Why can you not recover without antibiotics

Answer 3

heart valves dont have capillaries running along them, so infeciton on surface of heart valve - ends up havign infeciton where there are no blood vessles to bring neutrophils , and instead the neutrophils come from travelign in lungs deliverd by pulmonary veins and flow past mitral valve and out up the aorta

• and it is traveling at a speed which doesnt allow them to stick
• can never survive unlesshave antibiotic treatmnet becasue it cannot get neutrophils in

Question 4

Pathogenesis

Answer 4

• generally occurs to people with an abnormal heart valve - usually mitral or aortic could be due to rheumatic fever, or genetic
• leads to rough surface, and then can get platelets and firbin attatchign to the damaged valvular epithelium which form vegetations
• organsims living in the mouth can get out when chewing on food and get into capilaries and get into blood
• neutrophils usually kill them
• howver these types of bacteria can easily stikc onto platelets and firbin and some can stick onto heart valve with the fibrin platelet clot
• also could be due to staph in nose and this can also stick to the heart valves
• infected vegetation enlarges and sheds infected emboli and leads to vavlular destruction

Question 5

Diagnosing endocarditis

Answer 5

• high conc of bacteria in and on vegetation, bacteria shedding from vegetation into blood
• “constant bacteraemia”
• organsims will be constantly falling off the heart valve and into the blood so take blood ever 30 mins then will have it all the time as it is consantly breakign off - and will cotnain the same organsims causing this

Question 6

True bacteraemia
Contaminant bacteraemia
Transient bacteraemia

Answer 6

True - pathogens cultured that can cause infective endocarditis

COntaimnant - skin commensal curutred, only one set of positive cultures , no apparent infective source

Transient bacteraemia
-gut or mouth organism cultured, blood cultures only positive briefly

Question 7

Treatment

Answer 7

Dependant on organism, but always IV

• high dose
• usually at least 2 weeks, often 4 weeks

Question 8

rheumatic fever confusion with endocarditis

Answer 8

Endocardi)s
-get bloods 
viridans streptococci + others
mouth commensals
infec)on of valves
vegeta)ons on valves
treatment with IV penicillin for one month
prophylaxis with oral penicillin when dental work

Rheuma)c Fever
-take throat swab
Streptococcus pyogenes only pharyngi)s
immunologic damage to valves nodules on valves
treatment with oral penicillin for 10 days
prophylaxis with IM penicillin for many years

Question 9

Main cause

what antibiotic treatment ?

Answer 9

Viridans streptococci - in mouth

• only really cause this
• can stick to heart valves
• aplha haemolysis

Pencillin