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Infectious Diseases > Infective endocarditis > Flashcards

Infective endocarditis Flashcards

1
Q

TTE vs TOE for diagnosis of endocarditis

Other investigations used in infective endocarditis

A
  • TTE and TOE have similar specificity but TTE sensitivity much lower for endocarditis
    • TTE sen 70% (50% in PVE) - better day 5-7, consider repeat if initial negative and high clinical suspicion
    • TOE sen 96% (92% PVE)
    • Generally start with TTE. Recommend TOE after (particularly if prosthetic valve/cardiac device) regardless if negative or positive (exception if right sided valve involvement with good images)
  • ECHO criteria for infective endocarditis:
    • Vegetations
    • Aortic root abscess
    • Valve regurgitations

Other investigations:

  • Multi-slice CT can be used to detect abscesses with a diagnostic accuracy similar TOE
  • MRI → cerebral MRI greater sensitivity than CT in identifying cerebral complications of IE → significant as in a non-definite IE case, confirming cerebral complications gives you a minor Duke Criterion
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2
Q

Valves involved in endocarditis

A
  • Incidence of endocarditis higher in bioprosthetic valves rather than mechanical valves
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3
Q

Predisposing conditions associated with infective endocarditis

A
  • Current IV drug use
  • Previous IE
  • Invasive procedure in last 60 days
  • Chronic iV access
  • Endocavitary device → pacemaker, ICD
  • Congential heart disease
  • Native valve predisposition
  • Generally native valve > prosthetic valve > paemaker/ICD
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4
Q

Microbiologic aetiology of infective endocarditis

A

In order of most common

  • Staph. aureus
  • Viridans group streptococci e.g. strep mutans group, strep sanguinis group, strep mitis group
  • Coagulase negative staphylocci → mostly prosthetic valve, or pacemaker/ICD associated
  • Enterococci
  • Strep bovis and other strep
  • HACEK organisms → Haemophilus species, Aggregatibacter species, Actinomycetemcomitans, cardiobacterium hominis, eikenella corrodens, kingella kingae
  • Fungi/years
  • Polymicrobial (1%)
  • 10% culture negative

Considerations in elderly:

  • Higher prevalence of CONS, enterococci, strep gallolyticus (predisposing bowel lesions) - consider colonscopy
  • Drug regimens more likely to cause toxicity
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5
Q

Management of enterococcus faecalis endocarditis

A
  • Penicillin/amoxicillin 4-6 weeks PLUS gentamicin OD for 2-4 weeks
  • If CrcL <50 → Ampicillin + ceftriaxone (6 weeks)

Ampicillin + ceftriaxone as effective as amoxicillin + gent and safer

Gent can be given as single daily dose and safely shortened from 4-6 week course to 2 weeks only

All enterococci

Reduced susceptibility to beta lactam antibiotics, decreases susceptibility to amoxicillin, penicillin. High level resistance to cephalosporins → requires addition of synnergy antibiotic to increase cure rates

  • Addition of gentamicin → 4 log reduction in colony count
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6
Q

RCTs looking at PO antibiotics for treatment of infective endocarditis

A

Iversen et al NEJM 2019 (POET Study)

  • Left sided endocarditis, staphlycocci, streptococci, enterococci and coagulase negative staphylococci
  • IV treatment vs switch to 2 x PO antibiotics (each with a different mechanism of action)
  • Primary end point
    • All cause mortality
    • Unplanned cardiac surgery
    • Embolic event
    • Relapse of bacteraemia within 6 months
  • PO arm non inferior
    • First study of its type - needs to be repeated
    • Very select group
    • Not all organisms responsible for endocarditis included
    • Argument that a lot of patients could have been cured by the time they were randomised (all got 10 days IV antibiotics before randomisation)
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7
Q

Empiric therapy native valve endocarditis

A
  • Benzylpenicillin 1.8g Q4H

PLUS

  • Flucloxacillin 2g Q4H

PLUS

  • Gentamicin

Flucloxacillin more effective than vancomycin for MSSA staph - if risk for MRSA replace benpen with vancomycin

If pen allergic → cefazolin + vanc + gent

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8
Q

Empiric treatment of prosthetic valve endocarditis

A
  • Fluclox + vanc + gent
  • Pen allergic → replace fluclox with cefazolin
  • Needs cardiothoracic surgery involvement
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9
Q

Treatment of viridans group streptococci endocarditis

A
  • 4 weeks ben pen or ceftriaxone

OR

  • 2 weeks ben pen/ceftriaxone PLUS gentamicin
    • Synergistic killing effect on VGS and S. gallolyticus
    • Cure rates similar to those with 4 weeks monotherapy
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10
Q

Treatment of MSSA infective endocarditis

A
  • Flucloxacillin 2g Q4H 4-6 weeks
  • Pen allergic → cafazolin
  • Vancomycin is delayed severe hypersensitivity (desensitise if immediate)

Prosthetic valve endocarditis

  • Flucloxacillin 12g/day for 6 weeks
  • Some guidelines suggest rifampicin + gentamicin but significant toxicities
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11
Q

Treatment of MRSA infective endocarditis

A

Native valve endocarditis

  • IV vancomycin 6/52
    • Ceftaroline, daptomycin, linezolid (or adding cefazolin for synergistic effect) are other options

Prosthetic valve endocarditis

  • Evidence poor, high mortality
  • Some Guidelines add rifampicin and gentamicin for PVE as with MSSA but risk of toxicities
  • Consult with cardiothoracics
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12
Q

Notes on culture negative endocarditis

A
  • IE with x3 negative blood cultures after 7 days
  • Usually due to previous antibiotics
  • Fastidious organisms
    • Q fever, bartonella, streps, legionella, whipples, mycoplasma hominis, chlamydophila, fungi, brucella
    • Can’t be cultured lol → coxiella burnetii, bordatella, chlamydia, legionella
  • Ceftriaxone 2g OD 4-6 weeks for HACEK organisms
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13
Q

Notes on prosthetic valve endocarditis

A
  • Longer courses of therapy (+6 weeks therapy). Consider adding rifampicin for S. aureus
  • TOE mandatory for diagnosis
  • PET may have a role
  • Poorer prognosis (often older, comorbid)
  • Early → perioperative contamination
    • Usually involves junction between sewing ring and annulus - more likely to get perivalvular abscess and dehiscence
  • Late
    • Often on the leaflets
    • Similar micro to NVE
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14
Q

Notes on right sided infective endocarditis

A
  • 5-10% IE, often IVDU
    • Also cardiac devices, congenital heart disease
  • Right sided vegetations - lower bacterial densities
  • Staph. aureus 60-90%
  • Often two weeks of treatment is sufficient
    • If bacteraemia cleared quickly, no large vegetations or septic pulmonary emboli or complications
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15
Q

Indications for surgery in infective endocarditis

A
  • Severe AR or MR
  • Heart failure (from valve dysfunction) - most freqent complication and most common indication for surgery
  • Fungal or MDR organism
  • Perivalvular abscess
  • Prosthetic valve endocarditis
  • Uncontrolled infection, ongoing emboli on therapy/persistent bacteraemia
  • Size of vegetation (>1cm)
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16
Q

Notes on cardiac device infections

A
  • Either local device infection OR cardiac device related infective endocarditis (extending to electrode leads, cardiac valve leaflets, or endocardial surface)
    • Hard to defferentiate in practice
  • Staphylococci, and especially CONS, account for 60-80%
  • Need to remove hardware, often do 4-6 weeks (minimum 2 weeks post removal)
17
Q

Cardiac conditions for which endocarditis prophylaxis is recommended

A
  • Prosthetic heart valve
  • Rheumatic valvular heart disease
  • Previous endocarditis
  • Unrepaired cyanotic congenital heart disease
  • Surgical or catheter repair of congenital heart disease within 6 months of repair procedure

Prophylaxis required for:

  • All dental procedures involving manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa
  • Tonsillectomy/adenoidectomy
  • Procedures involving infected tissues (for which you would be giving antibiotics anyway)
  • ?Lithotripsy

Antibiotics - amoxicillin, clindamycin if pen allergic (for dental procedures)

18
Q

General measures for prevention of endocarditis in medium- to high-risk individuals

A
19
Q

Notes on microbiological diagnosis of infective endocarditis

A
  • 3 sets of blood cultures 30 minutes apart
  • When organism identified → should repeat cultures after 48 - 72 hours to determine if cleared
  • Pathological examination of resected valvular tissue/embolic fragments → gold standard for diagnosis IE
  • When high clinical suspicion and cultures remain negative after 48 hours → look for fastidious organisms and add on ANA, RF, antiphospholipid antibodies +/- anti-pork antibodies if bio-prosthetic valve
20
Q

Diagnostic criteria for infective endocarditis

A

Definite IE

  • Pathological criteria
    • Microorganisms demonstrated by culture or on histological exam of a vege, vege that hsa embolised or intracardiac abscess or
    • Patholigcal lesions; vegetation/intracardiac abscess confirmed by histological exam showing active endocarditis
  • Clinical critera
    • 2 major criteria or
    • 1 major criterion and 3 minor criteria or
    • 5 minor criteria

Possible IE

  • 2 major and 1 minor
  • 3 minor

Rejected IE

  • Resolution of symptoms suggesting IE with antibiotics therapy ≤4 days
  • No pathological evidence IE at surgery or autopsy
21
Q

Predictors of poor outcome in patients with infective endocarditis

A
22
Q

Complications of infective endocarditis

A
  • Heart failure
    • Usually due to new/worsening MR/AR
    • In NVE often aortic > mitral
  • Perivalvular extension of infection
    • Abscess, psuedoaneursyms, fistulae
    • Poor prognosis, high liklihood of need for surgery
  • Systemic embolism (20-50%) → risk highest first 2 weeks therapy
    • CNS → stroke, TIA, haemorrhage, brain abscess, meningitis. Seen in S.aureus more commonly than other organisms
    • Spleen → emboli common and often asymptomatic. Abscess uncommon.
    • Myocarditis and pericarditis
    • Conduction disturbances → uncommon - mainly heart blocks and generally associated with perivalvular complications
    • MSK → frequent athralgia, myalgia, back pain. Can see vertebral osteomyelitis.
    • Acute renal failure → immune complex and vasculitic GN, renal infarction (septic emboli), haemodynamic (severe sepsis, cardiac surgery), AIN related to antibiotics
23
Q

Factors associated with increased risk of relapses

A

Infectious Diseases (10 decks)

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