Infective Endocarditis Flashcards
Define infective endocarditis. What are the layers of the heart?
Infection of the endocardial structures (mainly heart valves)
Endocardium, myocardium, epicardium (in to out)
What is the aetiology of infective endocarditis? What organisms are most implicated?
- Streptococci - S. viridans in developing countries in dental work; low virulence but it affects those with abnormal valves
-
Staphylococci - MOST COMMON
- S. epidermis in new prosthetic heart valves (<2 months then
- S.aureus is most common again; S.aureus in drug use because skin commensal; higher virulence so it just needs introduction.
- Enterococci - streptococcus bovis in colorectal cancer (subtype of gallolyticus)
- Culture negative – HACEK will show negative blood culture
Mechanisms of entry:
- Prosthetic valve
- Intravenous drug abuse
- Pneumonia
- Dental work
- Indwelling lines
- Colonic malignancy
- Chronic cholecystitis
- Miscarriage
What are the causes of culture negative infective endocarditis?
Prior antibiotics therapy
Coxiella burnetti
Bartonella
Brucella
HACEK:
- haemophilus
- actinobacillus
- cardiobacterium
- ekinella
- kingella
How common is infective endocarditis?
Becoming more frequent
10,000 consultations for endocarditis in 2019/20 compared to 4000 in 2009/10 in England
Which organisms in IE are associated with:
- IV drug use
- prosthetic heart valves
- dental work
- colorectal malignancy
IV drug use → staphylococcus aureus
Prosthetic heart valves → staphylococcus epidermis
Dental work → streptococcus viridans
Colorectal malignancy → streptococcus bovis
What are the risk factors for IE?
RFs:
- Previous endocarditis
- Abnormal valves (e.g. congenital heart disease, post-rheumatic, calcification/degeneration with age)
- Prosthetic heart valves – bacteria loving because foreign
- IV drug use, IV catheters
- Turbulent flow (e.g. PDA or VSD)
- Recent dental work
What are the symptoms of infective endocarditis?
Symptoms:
- Fever, sweats, chills, rigors
- Malaise, arthralgia, myalgia, confusion
- Usually no chest pain in infective endocarditis (whereas present in pericarditis) - unless there is ischaemia due to decompensated heart failure
What are the signs of infective endocarditis?
Signs:
- Pyrexia , tachycardia
- New murmur (90%) : mitral > aortic > tricuspid> pulmonary (which ones get hit first with infected blood). Left site of the heart is affected less commonly. Right heart is more associated with IV drug use – right side murmurs are otherwise rare.
- Petechiae
- Clubbing 10%
- Haematuria 70%
- Splenomegaly 40%
- Vasculitic lesions - due to dislodgement of vegetation into small vessels
- Osler’s nodes (OUCH - painful on joints)
- Janeway lesions (not painful)
- Roth spots - on retina
- Splinter haemorrhages
What is the mnemonic for infective endocarditis signs?
How do you diagnose infective endocarditis?
Use Modified Duke criteria for diagnosis
- 3 sets of blood cultures - ideally at 30min intervals but do not delay if patient is unwell with sepsis, use different sites 10ml each in case of infection of lines
- Transthoracic echo (TTE) – to delineate the valves. before antibiotics to confirm infective endocarditis (TOE if uncertain)
Other:
-
Bloods –
- FBC(high neutrophils/polymorphs, normocytic anaemia),
- ESR, CRP - mildly raised
- U&Es - normal/high urea
- Rheumatic factor
- Complement - decreased (rarely done)
- Serology
- Urinalysis - may show RBC casts or microscopic haematuria
- CT/MRI - for valvular abnormalities and vegetation
Which organisms require serology rather than culture to be detected?
Serology may be needed for some atypical organisms e.g. Coxiella burnetti (Q fever), Bartonella and Brucella.
NB: cultures should not be taken from indwelling lines.
How do you manage infective endocarditis?
Management - depends if native or prosthetic valve and whether culture organism is known
MEDICAL
A-E approach if unwell
Follow local guidelines for initial blind abx therapy - usually:
- Native valve → amoxicillin +/- gentamicin
- Penicillin allergic → vanc + gentamicin
- Prosthetic → vanc + rifampicin + gentamicin
Continue for 4-6 weeks and monitor with BC. Change once culture results are back.
Antibiotics by cause:
Staphylococci
- Native → flucloxacillin (penicillin allergic: vanc+ rifampicin)
- Prosthetic → flucloxacillin + rifampicin + gentamicin (penicillin allergic: vanc + rifampicin + gentamicin)
Streptococci (e.g. viridans)
- Benpen (penicillin allergic: vanc + gentamicin)
- Less sensitive strep: benpen + gentamicin (penicillin allergic: vanc + gentamicin)
SURGICAL if:
- severe valve disease
- aortic abscess (prolonged PR)
- resistant infection
- cardiac failure refractory to meds
- recurrent emboli
What are the complications of IE?
Complications
- Congestive HF
- Valve incompetence
- Aneurysm formation
- Systemic embolisation
- Renal failure
- Glomerulonephritis
Other:
- Complete heart block
- Transient ischaemic attack
- Acute kidney injury- often multifactorial; septic emboli leading to infarction of abscess formation; drug induced; immune related glomerulonephritis
- Heart failure
- Vertebral osteomyelitis
D – no clubbing in pericarditis because it is more acute.
Blood in the stools, diarrhoea = colorectal cancer. This is a cancer associated with infective endocarditis.
Streptococcus bovis is associated with colorectal cancer.
Is a patient has ___ , raised ____ and new _____, this is infective endocarditis until proven otherwise.
Fever
Rasied ESR
Presumed new heart murmur
What is the diagnostic criteria for infective endocarditis?
Modified Duke criteria
Diagnosed if:
- pathological criteria positive OR
- 2 major OR
- 1 major 3 minor OR
- 5 minor
Pathological criteria = positive histology/microbiology of pathological material obtained at autopsy or surgery e.g. vegetations, emboli fragment, abscess.
Major criteria (bloods or echo)
- 2+ve BC with typical organisms e.g. S. viridans and HACEK OR
- 2+ve BC from cultures taken >12hrs apart OR
- 3+ve BC where pathogen is less specific (e.g. S.aureus or epidermidis)
- 1+ve serology for Coxiella burnetti, Bartonella or Chlamydia psittaci
- +ve molecular assay for specific gene targets
- +ve echo findings of vegetation
- New valvular regurgitation
Minor criteria
- Predisposition (cardiac lesion, IV drug abuse);
- Fever >38 °C
- Vascular signs, e.g. arterial emboli, Janeway lesions, splenomegaly, splinter haemorrhages, mycotic aneurysms
- Immunological signs e.g. Oslers nodes, Roth spots, glomerulonephritis
- Microbiological evidence but not fitting major criteria
What is the prognosis in native and prosthetic valve endocarditis?
Survival is 80-90% at 1yr after native valve endocarditis
Mortality is 40% in prosthetic valve endocarditis at 1yr
Name 2 causes of non-infective endocarditis.
SLE (Libman-Sacks)
Malignancy - marantic endocarditis
What is shown?
Osler nodes - Ouch → painful on the pads of fingers or toes
What is shown?
Janeway lesions - painless on palms and soles
What is shown?
Roth spots - oval pale retinal lesions surrounded by haemorrhage detected on fundoscopy
What does the arrow indicate in this TOE of endocarditis?
Vegetation on the aortic valve - repeat this within 5-7 days if initial scan is negative but suspicion is high
What ECG feature in IE may indicate aortic abscess?
Lengthening PR interval
