Infetive endocarditis Flashcards
what is infective endocardittis?
Infection of the
endocardium
(endothelial lining) of
the heart
Usually occurs on the
heart valves
Can involve septal
defects and mural
surfaces and prosthetic
devices(pacemaker
wires)
pathogenissi?
Endothelium becomes damaged by
- Trauma
- Congenital defects
- Previous disease
microorganisms adhere to the
endothelial surface
Triggers an inflammatory and immune
response
vegegation path
predisposing factors
Heart defects
- Congenital
(VSD, biscupid AV, prolapsed MV, (ASD))
Acquired
- Rheumatic heart disease
- Atherosclerotic degeneration
- Valve replacement (prosthetic, homograft)
Prosthetic devices
- Intravenous long lines
- Pacemaker wires
Others
- Intravenous drug abuse
site
Maximum deposition of thrombus bacteria
occurs at sites of turbulent flow
- eg when blood is driven from a high to a low
pressure area
AV > MV > TV > PV
Exceptions
- Rheumatic heart disease predisposes infection of
the MV
- IV drug abuse (mainlining) and intravenous lines
predispose the right side of the heart
causative organisms
endocarditis
Sometimes referred to as
- Acute
(Rapidly fulminant course with death occurring within
days – weeks)
- Subacute (SBE)
(Indolent and prolonged course)
Based on progression of untreated disease as
determined by the virulence of the organism
Ignores frequent overlap of syndromes
Classification based on aetiology more
appropriate beacause it has implications for
management and treatment
clinical findings
Fever
Heart murmur (new or changing)
Peripheral signs
- splinter haemorrhages
- petechiae
- Osler’s nodes
- Janeway lesions
- Roth spots
Systemic emboli
Splenomegaly
Haematuria
Anaemia
lab findings
Blood cultures
- Positive in 90% of cases
Non-specific
- Evidence of infective process
( Raised WBC, anaemia, raised CRP/ESR)
- Evidence of immune complex disease
( Low complement levels, haematuria)
Cardiological
- Echocardiography
- ECG
culture negative endocaritis
Causes
- Previous antibiotics
- Non-culturable
(Rickettsiae, Chlamydiae) - Fastidious organisms
(Nutritionally dependent, Slow-growing) - Right-sided disease
duke criteria major
major
Positive blood cultures
- Typical organism (eg staph/strep) from 2 sets in
absence of a focus
- Persistent bacteraemia with organism from
( 2 sets drawn >12 hours apart, 3 out of 4 sets drawn one hour apart)
Evidence of endocardial involvement
- New valvular regurgitation
- Positive echocardiogram
(Oscillating intracardiac mass, Abscess)
- New or partial dehiscence of prosthetic valve
duke criterai minor
Predisposition
- Heart defect, prosthetic valve, drug abuse
Fever
Vascular phenomena
- Haemorrhage, emboli, infarcts
Immunological phenomena
- Splinters, Osler’s nodes, Roth spots
Blood cultures not meeting major criteria
Echo abnormality not meeting major criteria
Serological evidence of infection
(Raised CRP)
duiagnsis
Definite histological
- Pathologically confirmed by culture and
histology of specimen
Definite clinical
- 2 major criteria
- 1 major and 3 minor criteria
- 5 minor criteria
marantic vegetation
Marantic endocarditis, also known as non-bacterial thrombotic endocarditis (NBTE), is the deposition of small sterile vegetations on valve leaflets.
The previous term for nonbacterial thrombotic endocarditis (NBTE) was marantic endocarditis, from the Greek marantikos, meaning “wasting away.”[1]
The term “Marantic endocarditis” is still sometimes used to emphasize the association with a wasting state[2] such as cancer.[3]
Marantic vegetations are often associated with previous rheumatic fever.
Other risk factors include:
hypercoagulable states,
mucin-producing adenocarcinomas, (most commonly associated with pancreatic adenocarcinomas)
lupus and
trauma (e.g., catheters).
treatemtn
Use cidal antibiotics in synergic combinations
Use parenteral antibiotics for a minimum of 2
weeks (often 4 weeks required) before
switching to oral regimens for total of 6 weeks
Identify the organism wherever possible and
determine MICs
Synergic: the activity of the combination of antibiotics is greater
than the sum of the individual activities
MIC: minimum inhibitory concentration. The lowest
concentration of antibiotic required to inhibit growth of the
organism in vitro
antibiotic regime
