Infective Endocarditis and Other Cardiac Infections Flashcards
describe blood cultures
blood is normally sterile
the presence of bacteria in the bloodstream (bacteraemia) is a potentially life threatening event- if not treated promptly the patient may develop septic shock and die
which organisms are commonly found in cardiac implantable electronic devices?
staphylococcus aureus staphylococcus epidermidis corynebacterium sp. proprionibacterium acnes a biofilm can form
risk factors for ICED infections
pre procedure prophylaxis complexity of procedure temporary pacer use type of device number of revisions/ reinterventions fever within 24 hours heart failure, renal failure haematoma post procedure
generator pocket infection
localised cellulitis pain swelling discharge wound breakdown
clinical features of ICED-IE/ ICED-LI
non specific signs and symptoms of systemic infection including fevers, chills, night sweats, malaise and anorexia
may present with secondary foci such as spinal or pulmonary infection
what can be used to assist in the diagnosis of ICED-ID/ ICED-LI
Duke Criteria
infective endocarditis
infection of the endothelium of the heart valves
life threatening
may be acute or subacute
predisposing factors to infective endocarditis
heart valve abnormality - calcification/ sclerosis in elderly - congenital heart disease - post rheumatic fever prosthetic heart valve intravenous drug users intravascular lines
pathogenesis of endocarditis
heart valve damaged
turbulent blood flow over roughened endothelium
platelets/ fibrin deposited
bacteraemia
organisms settle in fibrin/ platelet thrombi becoming a microbial vegetation
infected vegetations are friable and break off, becoming lodged in the next capillary bed they encounter causing abscesses or haemorrhage
usually left side of heart affected (right side in drug users)
organisms causing endocarditis native valve
staphylococcs aureua
viridans group streptococci
enterococcus
staphylococcus epidermidis
unusual organisms causing endocarditis
atypical - bartonella - coxiella burnetti - chlamydia - legionella - mycoplasma - brucella gram negatives - HACEK organisms - haemophilus - aggregatibacter - cardiobacterium - eikenella - kingella - non HACEK gram negatives fungi
blood cultures positive for an IE
detection of an endocarditis specific pathogens in 2 independant blood cultures
-or-
microorganisms compatible with an IE persistenly positive blood cultures
-or-
a single positive blood culture with coxiella burnetti or a phase I IgG antibody titer > 1:800
taking blood cultures
Take 3 sets of blood cultures -very important since if all are positive there is good evidence of continuing bacteraemia. If only one set taken and is positive might be a contaminant. Better clinical outcome when causative organism is identified
Should be taken before any antibiotics
If blood cultures negative, consider serology for “atypical” organisms
staph epidermidis
Most common coagulase-negative Staphylococcus
Often a skin contaminant, BUT can infect prosthetic material e.g. Intravascular line infections, prosthetic heart valves/joints
Take more than one set of blood cultures to confirm significance
common skin contaminants
staph epidermidis
corynebacterium
presenting symptoms of acute endocarditis
Presents as overwhelming sepsis and cardiac failure
Usually due to aggressive (virulent) organisms such as Staphylococcus aureus
symptoms of subacute endocarditis
fever malaise weight loss tiredness breathlessness
signs of subacute endocarditis
fever new or changing heart murmur finger clubbing splinter haemorrhages splenomegaly roth spots janeway lesions osler nodes microscopic haematuria
viridans group streptococci
alpha haemolytic strep - strep mitis - strep sanguinis - strep mutans - strep salvarius subacute endocarditis - normal oral commensals - no lancefield group or capsule
investigations for infective endocarditis
transthoracic echocardiography
transoesophageal echocardiography
positive echocardiography for an IE
vegetation, abscess, pseudonaneurysm, intracardiac fistula, valve preforation, new partial dehiscence of a valve prothesis
prothetic valve endocarditis
Early (within 60 days) and late presentations
Early- usually infected at time of valve insertion and usually due to Staphylococcus epidermidis or Staphylococcus aureus
Late - up to many years after valve insertion - due to co-incidental bacteraemia. Wide range of possible organisms
endocarditis in PWID
Right-sided endocarditis (tricuspid > >mitral > aortic)
Usually Staphylococcus aureus
Suspect in Staphylococcus aureus plus septic pulmonary emboli
treatment for native valve endocarditis (viridans strep)
amoxicillin and gentamicin IV
treatment for prosthetic valve endocarditis
vancomycin and gentamicin IV
add in day 3 to 5 rifampicin PO
often valve replacement
treatment of drug user endocarditis (MSSA)
flucloxacillin IV
staphyloccocus aureus treatment
flucloxacillin IV
MRSA treatment
treat as per prosthetic valve
viridans strep treatment
benzylpenicillin IV and gentamicin IV
staph epidermidis treatment
vancomycin and gentamicin IV
rifampicin PO
monitoring treatment
IV antibiotics usually given for 4-6 weeks
Monitor cardiac function, temperature and serum C-reactive protein (CRP)
If failing on antibiotic therapy, consider referral for surgery early
patient characteristics increasing mortality
older age
prosthetic valve IE
diabetes mellitus
comorbidity
clinical complications increasing mortality
heart failure renal failure moderate area of ischaemic stroke brain ahaemorrhage septic shock
microorganisms increasing mortality
staph aureus
fungi
non HACEK gram- bacilli
myocarditis
more common in young people
mainly causes by enteroviruses- Coxsackie A & B, echovirus, but other viruses possible the list is extensive.
Diagnosed by viral PCR. Throat swab and stool for enteroviruses. Throat swab for influenza
Supportive treatment
symptoms of myocarditis
fever
chest pain
SoB
palpitations
signs of myocarditis
arrhythmia
cardiac failure
pericarditis
Often occurs with myocarditis
Chest pain main feature
Viral aetiology mainly, Supportive treatment
bacteria less common
e.g post cardiothoracic surgery, rarely secondary spread from endocarditis or pneumonia treatment : antibiotics & drainage
