Endocarditis Flashcards
How is endocarditis classified?
Infective endocarditis (IE)
Non-infective endocarditis (NIE)
What is endocarditis?
Inflammation of the endocardium of the heart
Often involves the heart valves
What is the hallmark sign of endocarditis?
Fever + murmur
What is the most common organism that causes IE?
Streptococcus viridans
Name other cocci that causes IE
Staphylococcus aureus (common)
Staphylococcus epidermidis - usually after prosthetic valve surgery
Strep bovis (needs colonoscopy, ?tumour)
Enterococci
Coxiella burnetti
What are the HACEK gram -ve bacteria that can cause IE?
Haemophilus
Actinobacillus
Cardioacterium
Eikenella
Kingella
Name other bacterial and fungal causes of IE
Bacteria
- diphtheroids
- Chlamydia
Fungi
- Candida
- Aspergillus
- Histoplasma
Which patient demographics are at increased risk of IE?
IV drugs user
Immunocompromised
Prosthetic valves
Congenital heart disease
Hypertrophic cardiomyopathy
Previous Hx of IE
Valvular heart disease
People with rheumatic fever - can cause rheumatic heart disease (which can cause IE); organism = Strep pyogenes
What are the septic signs of IE?
Fever
Rigors
Weight loss
Anaemia
Night sweats
Clubbing
Splenomegaly
What are the signs of IE?
Septic
Cardiac lesions
Immune complex deposition
Embolic phenomena
What are cardiac lesions?
Vegetations on the valves - can cause destruction and severe regurgitation, or valve obstruction
Any new murmur/change in pre-existing murmur should raise suspicion of endocarditis
How can cardiac lesions affect the ECG?
PR prolongation (caused by aortic root abscesses)
Can eventually lead to complete AV block
Name a common cause of death in IE
LVF
What conditions/signs in IE are caused by immune complex deposition?
Vasculitis
Microscopic haematuria - glomerulonephritis and AKI may occur
Roth spots - boat shaped retinal haemorrhage with pale centre
Splinter haemorrhages
Osler’s node - painful pulp infarcts in fingers and toes
What conditions/signs in IE are caused by embolic phenomena?
Abscesses in relevant organ e.g., kidney, spleen, liver
Janeway lesions - painless, palmar or plantar macules
Which criteria is used in the diagnosis of IE?
Modified Duke’s Criteria
What are the components of the Modified Duke’s Criteria for IE?
What other diagnostic tests can be done for IE?
Blood cultures - 3 at different times and different sites at the peak of fever
- 85-90% diagnosed from 1st 2 sets
- 10% are culture-negative
Bloods
- FBC - normochromic, normocytic anaemia, neutrophilia
- ESR/CRP - high
- RF
- U+E
- LFT
- Mg2+
Urinalysis
- microscopic haematuria
CXR
- pulmonary oedema
- cardiomegaly
Regular ECGs
- look for heart block
Echocardiogram
- vegetations > 2mm
CT
- emboli (spleen, brain etc)
What is the initial ‘blind’ therapy for IE (native valve)?
Amoxicillin/ampicillin - consider adding low-dose gentamicin
If penicillin-allergic/MRSA suspected/severe sepsis = vancomycin + low does gentamicin
If severe sepsis + risk factors for Gram -ve infection = vancomycin + meropenem
What is the therapy for IE (native valve) caused by staphylococci?
Flucloxacillin + rifampicin + low-dose gentamicin - for 6 weeks, review need to continue gentamicin at 2 weeks; if gentamicin to be continued beyond 2 weeks seek specialist advice
If penicillin-allergic/MRSA = vancomycin + rifampicin + low-dose gentamicin - for 6 weeks, review need to continue gentamicin at 2 weeks; if gentamicin to be continued beyond 2 weeks seek specialist advice
What is the therapy for IE caused by fully-sensitive streptococci?
Benzylpenicillin sodium - 4-6 weeks (6 weeks for prosthetic valve)
If penicillin allergic = vancomycin (or teicoplanin) + low-dose gentamicin - for 4-6 weeks (stop gentamicin after 2 weeks)
What is the therapy for IE caused by less-sensitive streptococci?
Benzylpenicillin sodium + low dose gentamicin - 4-6 weeks (6 weeks for prosthetic valve), review need to continue gentamicin at 2 weeks; if gentamicin to be continued beyond 2 weeks seek specialist advice
If penicillin allergic or highly penicillin resistant = vancomycin (or teicoplanin) + low-dose gentamicin - for 4-6 weeks , review need to continue gentamicin at 2 weeks; if gentamicin to be continued beyond 2 weeks seek specialist advice, stop at 2 weeks if pathogens moderately sensitive to penicillin
What is the therapy for IE caused by enterococci?
Amoxicillin/ampicillin + ((low dose gentamicin) OR (benzylpenicillin sodium + low-dose gentamicin))
for 4-6 weeks (stop gentamicin after 2 weeks), review need to continue gentamicin at 2 weeks; if gentamicin to be continued beyond 2 weeks seek specialist advice
If penicillin-allergic or highly penicillin resistant = vancomycin (or teicoplanin) + low-dose gentamicin - for 4-6 weeks , review need to continue gentamicin at 2 weeks; if gentamicin to be continued beyond 2 weeks seek specialist advice
If gentamicin resistant = amoxicillin/ampicillin, add streptomycin (if susceptible) for 2 weeks
Suggested duration of Tx = at least 6 weeks
What is the therapy for IE caused by HACEK?
Amoxicillin/ampicillin + low dose gentamicin for 4 weeks (6 weeks for prosthetic valve); stop gentamicin after 2 weeks
If amoxicillin-resistant = ceftriaxone (or cefotaxime) + low dose gentamicin for 4 weeks (6 weeks for prosthetic valve); stop gentamicin after 2 weeks
What is the initial ‘blind’ therapy for IE (prosthetic valve)?
Vancomycin + rifampicin + low-dose gentamicin
What is the prognosis of IE?
50% require surgery
20% in-hospital mortality (overall)
- Staphs = 30%
- bowel bacteria = 14%
- Streps = 6%
15% recurrence at 2 years
TRUE OR FALSE
Antibiotic prophylaxis is no longer recommended for those at risk of IE undergoing invasive procedures
TRUE
However, if they are given Abx for other procedural reasons it should cover the common IE organisms
What info about prevention of IE can you give to patients?
Importance of maintaining good oral health
Symptoms that indicate IE and when to seek expert advice
The risk of invasive procedures inc. non-medical procedures e.g., body piercing or tattooing
What are the NIEs?
Nonbacterial thrombotic endocarditis (NBTE)
Libman-Sacks endocarditis
What are the characteristics of NBTE?
- most commonly found on previously undamaged valves
- vegetations are small, sterile and tend to aggregate along the edges of the valve or the cusps
- does not cause an inflammation response from the body
- usually occurs in a hypercoagulable state e.g., system-wide bacterial infection, pregnancy
- can also occur in patients with venous catheters
- can also occur in malignancies esp. mucinous adenocarcinoma
What are the characteristics of Libman-Sacks endocarditis?
- occurs more often in SLE
- thought to be due to deposition of immune complexes
- involves small vegetations (unlike NBTE) - IE contains large vegetations
- does not have a preferred location of deposition (unlike NBTE) - may form on the valves’ undersurfaces or even on the endocardium
- Mx = anticoagulant in cases with previous thromboembolic event for prevention, surgical intervention if significant valvular dysfunction
- has high morbidity and mortality
Sources
Pg 150 Oxford Handbook of Clinical Medicine
https://en.wikipedia.org/wiki/Endocarditis
https://en.wikipedia.org/wiki/Nonbacterial_thrombotic_endocarditis
https://en.wikipedia.org/wiki/Libman%E2%80%93Sacks_endocarditis
https://www.nhs.uk/conditions/endocarditis/causes/
https://bnf.nice.org.uk/treatment-summaries/cardiovascular-system-infections-antibacterial-therapy/
