38 Cardiology infections Flashcards
IE involves endothelial linings of the heart, usually including heart valves. Majority have pre-existing heart defect e.g rheumatic fever/ congenital/ prosthetic valve/ cardiac device
How do vegetations form?
Route of entry into bloodstream e.g dental work, urinary tract, GI tract
Organisms bind to fibrin-platelet vegetations on damaged valves/ endothelium
Multiply further, as protected by vegetation
Slow process, so from bacteraemia to symptoms can take 5 weeks
Which organisms cause native valve IE?
Most commonly affects aortic/ mitral valves
30% of infections can be classified as HAI - due to lines/ procedures
Staph aureus 30%
Coagulase negative staph 5%
Streptococci -
- viridans species - mutans/ sanguinis/ mitis 40%
- Group D - enterococcus 10%
Gram neg rods 5%
HACEK 5%
Candida
Culture negative 5-25%
Staph aureus is the most common in IVDU 70%
What are less common causes of native valve IE?
blood culture negative
Strep pneumoniae
Coagulase negative staph
If blood cultures negative test for - Haemophilus influenzae Brucella Bartonella Coxiella Chlamydia Legionella HACEK (if grown in wrong medium) Trephonema whipplei
What are causes of prosthetic valve IE?
Often divided into early (within 1 year of insertion) and late infection. There are microbiological differences in aetiology
Staph epidermidis 30%
Staph aureus 40%
Strep viridans <5%
Pseudomonas
Serratia marcescens
Diptherioids
HACEK
Fungi
Most patients with IE with have fever and murmur.
What are the modified duke criteria?
Major -
- typical organism demonstrated in culture or in vegetation in 2 separate blood cultures - Staph/ Strep/ HACEK
- one positive blood culture for coxiella burnetti
- vegetation showing endocardial involvement
Minor -
- fever
- predisposition - IVDU, predisposing heart condition
- vascular phenomena - Janeway lesions, septic emboli Splinter haemorrhages
- immunologic phenomena - Oslers nodes, Roth spots, glomerulonephritis (haematuria)
- microbiological evidence - blood culture is not typical for IE
Definite IE -
2 major
1 major 3 minor
5 minor
Possible IE -
1 major 1 minor
3 minor
What are investigations for IE?
Blood cultures - 3 sets, at different sites, with 6 hours between them
Urinalysis - haematuria
TTE/ TOE
Consider investigation for rarer organisms
May need PET/CT scan - look for uptake around valves. Only use if prosthetic valve been in situ for >3 months
IE has mortality rate between 20-50%, why is this?
Late presentation
Vegetation resistant to host defenses/ antibiotics
Vegetation has high bacterial desnity
What is treatment for IE?
Native valve - indolent presentation
Native valve - sepsis
Native valve - indolent presentation
- Amoxicillin 2g 4 hourly
- gentamicin 1mg/kg BD
Native valve - sepsis
- vancomycin
- gentamicin 1mg/kg BD
What is treatment for IE?
Prosthetic valve
Vancomycin
Gentamicin 1mg/kg BD
Rifampicin 600mg PO/IV BD
Proven Staphyloccal endocarditis (MSSA)
What is treatment?
Native valve
Prosthetic valve
Native valve
- flucloxacillin 2g IV QDS
Prosthetic valve
- flucloxacillin 2g QDS
- gentamicin 1mg/kg BD
- rifampicin 600mg BD
Switch flucloxacillin for vancomycin if MRSA
Proven Streptococcal endocarditis
What is treatment?
Native valve/ prosthetic valve is the same
Benzylpenicillin 1.2g 4 hourly
or
Ceftriaxone 2g OD - suitable for OPAT
Proven enterococcal endocarditis
What is treatment?
Amoxicillin 2g 4 hourly
Vancomycin if resistant - enterococci usually are
+
Gentamicin 1mg/kg BD
Swap amoxicillin for vancomycin if penicillin allergic
Coxiella burnetti is rare cause of IE
What are treatment options?
Treatment required for approx 3 years, depending on antibody response
Doxycyline + hydroxychloroquine
Doxycycline + ciprofloxacin
Proven candida endocarditis.
What are treatment options?
Caspofungin
or
Ambisome (amphotericin B
+
Flucytosine
Proven aspergillus endocarditis
What are treatment options?
Voriconazole (monitor levels)
or
Ambisome (amphotericin B
+
Flucytosine
Up to 50% of patients with IE will require cardiac surgery.
What are indications?
Any IE with existing prosthetic mateiral
Heart failure - severe regurgitation causing pulmonary oedema
Uncontrolled infection - abscess, aneurysm, persisting fever >10 days
Large vegetations - can cause embolic episodes should be removed
Sometimes antibiotics are required a prophylaxis in dental procedures.
Who is recommended to have prophylaxis?
Give amoxicillin 2g oral or clindamicin 600mg, 30-60min before procedure
- Previous endocarditis
- Valve (any) replacement
- Right to left shunts (e.g. cyanotic congenital heart disease)
- Or on the specific recommendation of consultant cardiologist following formal letter advising as such.
No prophylaxis for bronchoscopy/ endoscopy
What is typical duration of antibiotic therapy for IE?
4-6 weeks IV from date of negative blood culture
6 weeks IV from date of cardiac surgery, if valve culture was positive
Can be via OPAT
POET trial showed oral can be option for selected groups
Gentamicin dosing,
What levels should peak/ trough be?
trough <1mg/l
peak 3-5mg/l
Pericarditis and myocarditis can be caused by various pathogens.
What are the most common ones?
Viral - echovirus Enterovirus Coxsackie A + B CMV HBV EBV HIV
Bacteria Staph aureus Strep pneumoniae Mycoplasma TB
Other causes post-MI post-cardiac surgery uraemia drug induced trauma
With myocarditis/ pericarditis, what are risk factors necessitating admission?
Fever
Large pericardial effusion/ tamponade
Lack of response to aspirin/ NSAIDs
Which organism is associated with IE in context of bowel cancer?
Group D streptococcus - S gallolyticus (S Bovis)
Recommend colonoscopy. If negative, suggest repeat in 6 weeks time
If cardiac device being implanted, the perioperative antibiotics are given.
If patient is recovering from infection, how long should they wait before have cardiac device inserted?
2 weeks after infection
Which organisms are included in HACEK group?
- gram-negative coccobacillary organisms
- fastidious growth
- typically oropharyngeal commensals, but also GI/GU tract. So dental disease most common route of infection
Haemophilus species Aggregatibacter species Cardiobacterium hominis Eikenella corrodens Kingella species
The HACEK group accounts for approximately 5%-10% of community-acquired native-valve endocarditis
How does treatment differ in HACEK IE?
Generally resistant to ampicillin
Ceftriaxone is usual treatment
CT scan incidentally shows splenic infarcts.
What is significance of this?
Can indicate IE with septic emboli
Up to 30% patients with IE develop renal failure.
Why is this?
Drug induced
Immune complex deposition
Renal infarction - micro emboli
Under-perfusion - heart failure
Patient with PPM, presents with fever, raised CRP.
ECHO shows no vegetations. Suspecting device infection.
What is treatment?
Remove device
Flucloxacillin + rifampicin
6 weeks
Rifampicin helps with biofilms
Switch flucloxacillin to vancomycin in MRSA suspected
