Week 5/6 - F - Endocarditis - acute/subacute - symptoms, risk factors, organisms, diagnosis/criteria, empirical / specific treatment

Question 1

What is a fever + new murmur thought to be until proven otherwise?

Answer 1

Infective endocarditis

Question 2

What is infective endocarditis?

Answer 2

Infective endocarditis is an infection of the endothelium of the heart valves - it is a life threatening condition

Question 3

IE can be acute or subacute in presentation What is the difference between acute and subacute endocarditis?

Answer 3

Acute IE occurs over days to weeks in patient’s with previously normal heart valves Sub-acute IE occurs usually over weeks to months i patients who already have previously damaged heart valves

Question 4

What are the different presentations of acute and subacute endocarditis?

Answer 4

Acute endocarditis occurs over days to weeks and begins suddenly with fever, fast heart rate, and rapid/extensive heart damage - patients present with sepsis Subacute endocarditis occurs over weeks to months with mild fever, moderate tachycardia, weight loss, fatigue (shows gradual presentation)

Question 5

What are the risk factors predisposing to infective endocarditis?

Answer 5

Heart valve abnormalities - * eg calcification/sclerosis in the elderly * congenital heart disease * post rheumatic fever Prosthetic heart valve IV drug users Intravascular lines

Question 6

Describe the pathogenesis of endocarditis?

Answer 6

Heart valve becomes damaged Turbulent blood flow then happens over the roughened endothelium causing endothelial damage Platelet plug / fibrin mesh deposits and bcomes a non-bacterial thrombus Transient bacteraemia then occurs eg from dental treatment This adheres to the thrombus and proliferates Becomes a microbial vegetation

Question 7

What is the most common cause of native valve acute and subacute endocarditis?

Answer 7

Most common cause of native valve acute endocarditis is staph aureus Most common cause of native valve subacute endocarditis is strep viridans

Question 8

Staph aureus and strep viridans are the two most common causes of native valve endocarditis, what are the other common causes?

Answer 8

Enteroccus and staph epidermis

Question 9

What are atypical organisms causing endocartitis?

Answer 9

Atypical organism - coxiella burnetti, legionella, mycoplasma Gram negatives (rare) - * HACEK organisms - Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella) Fungi

Question 10

Where do all the HACEK organisms that rarely cause IE colonise?

Answer 10

The HACEK organisms are a normal part of the human microbiota, living in the oral-pharyngeal region

Question 11

Why does the treatment of endocarditis involve high dose, IV antibiotics for prolonged times and using bacterocidal antibitoics?

Answer 11

Endocarditis is a deep seated infection and therefore high dose IV treatment is required Also it is given in high dose to penetrate vegetations, eliminate bacteria and to reduce the risk of septic emboli Bactericidal antibiotics are given to kill rather than slow bacteria

Question 12

How long are the high dose, prolonged duration course of bactericidal antibiotics given for in endocarditis?

Answer 12

Endocarditis treatment is prescribed for 4-6 weeks to ensure elimination of the bacteria

Question 13

What is the presentation of acute endocarditis?

Answer 13

Patient presents with overwhelming sepsis Fever, rigors, night sweats and cardiac failure

Question 14

What are the subacute presentations of bacterial endocarditis?

Answer 14

Fever, malaise, weight loss, tiredness and breathlessness New or changing heart murmur Flinger clubbing Splinter haemorrhages Splenomegaly Microscopic haematuria

Question 15

What are the vascular and immunological phenomena that can be seen in endocarditis? (usually in subacute)

Answer 15

Vascular phenomena - Emboli Janeway’s lesions - painless lesions - erythematous papules on palms and soles Immunological phenomena (immune complex depositiion) - Glomerulonephritis Osler’s nodes - painful nodules on tips of digits Roth spots - retinal haemorrhages with pale centers

Question 16

What is the criteria used to diagnose a patient with infective endocarditis? Don’t need to remember the exact points of the criteria. Just state what the major criteria are? What is needed from the modifed Duke’s criteria to diagnose infective endocarditis?

Answer 16

This would be the modified Duke Criteria Major criteria is blood culture positive and evidence of echocardial involvement For IE diagnosis, need * 2 major criteria or * 1 major and 3 minor criteria * All 5 major criteria

Question 17

If you have a clinical suspicion of endocarditis what tests are carried out?

Answer 17

Blood cultures Transthoracic echocardiography Blood tests U&Es, LFTs CXR CT to look for emboli

Question 18

Meticulous aseptic technique is required when taking blood cultures for IE to prevent contaminant with skin commensals. How are cultures taken and when are antibiotics started: In patients with suspected infective endocarditis and severe sepsis or septic shock at the time of presentation? (acute) In patients with an indolent (also known as chronic or subacute) presentation?

Answer 18

In patients with suspected bacterial endocarditis and severe sepsis - 2 optimally filled sets of blood cultures are taken at different times within one hour, prior to commencing empirical antibiotic therapy In patients with indolent (aka chronic or subacute) presentation, 3 optimally filled sets of blood cultures with >/= 6 hours apart, prior to commencing empirical antibiotic therapy

Question 19

After patients have had the transthoracic echocardiography, what is carried out if this is positive?

Answer 19

Transtoesophgeal echocardiography - more sensitive and better visualisation

Question 20

How are cultures taken and when are antibiotics started: In patients with suspected infective endocarditis and severe sepsis or septic shock at the time of presentation? What is the empirical therapy for patients presenting with native valve acute endocarditis?

Answer 20

In patients presenting with suspected BE and severe sepsis or septic shock - 2 sets of blood cultures are taken within one hour prior to starting antibiotic therapy Empirical antibiotics of choice for native valve acute BE - Needs to provide cover for main causative organism, staph aureus Flucloxacillin IV is treatment of choice

Question 21

How are cultures taken and when are antibiotics started: In patients with an indolent (also known as chronic or subacute) presentation? What is the empirical therapy for patients presenting with native valve indolent endocarditis?

Answer 21

In patients with an indolent presentation, 3 sets of optimally filled cultures are taken >/= 6 hours apart prior to commencing antibiotics therapy Empirical therapy for patients presenting with native valve subacute endocarditis - IV amoxicillin and Gentamicin

Question 22

What are the causative organisms usually in prosthetic valve endocarditis?

Answer 22

Causative organism usually due to staph epidermis or staphylococcus aureus

Question 23

What is the empirical treatment for patients with prosthetic valve endocarditis? Same as treatment for patients with native valve if MRSA suspected?

Answer 23

This would be IV Vancomycin, gentamicin and rifampicin PO Usually valve replacement will be required

Question 24

What is the most common cause of endocarditis in people who inject drugs (PWIDs)? Which side of the heart does this effect usually? When should it be suspected? What is the treatment?

Answer 24

Endocarditis in PWID - caused usually by staph aureus Affects the right side of the heart - tricuspid valve Suspect in patients with staph aureus plus septic pulmonary emboli Treatment is IV flucloxacillin

Question 25

Which is the most common bacteria indicated in * Patient who has recieved dental work? * Prosthetic valve? * Acute native valve? * Subacute native valve? * PWID?

Answer 25

* Patient who has received dental work? - strep viridans * Prosthetic valve? - staph auerus or staph epidermis * Acute native valve - staph aureus * Subacute native valve - strep viridans * PWID - staph aurus

Question 26

SUMMARY - State the empirical treatments * Native valve acute endocarditis empirical? * Native valve subacute endocarditis empirical? * Prosthetic valve or native valve if MRSA suspected? * Drug user endocarditis?

Answer 26

Native valve acute endocarditis empirical - IV flucloxacillin Native valve subacute endocarditis empirical - IV amoxicillin and gentamicin Prosthetic valve or native valve if MRSA suspected - IV vacnomycin, gentamicin and PO rifampicin Drug user endocarditis - IV flucloxacillin

Question 27

State the treatments once the organism has been identified * Staph aureus (not MRSA) * Strep viridans * Enterococcus * Staph epidermis * MRSA

Answer 27

Staph aureus (not MRSA) - Flucloxacillin IV Strep viridans - IV Benzylpenicllin and gentamicin Enterococcus - IV amoxicllin (vancomycin if pen allergic) and IV gentamicin Staph epidermis and MRSA - IV vancomycin, gentamicin and PO rifampicin

Question 28

When is surgery recommended in the treatment of endocarditis?

Answer 28

Surgery if * Heart failure * Valvular obstruction * High risk emboli * Persistent sepsis * Fungal