infective endocarditis Flashcards by Sarah Anderson

What parts of the heart can be affected in infective endocarditis

infection of inner layer of heart
endocardium

heart valves:
native
prosthetic

interventricular septum
septal defect

chordae tendinae

intra-cardiac devices

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Why is infective endocarditis not a uniform disease

various presentations

possibly dependent on underlying cardiac disease

microorganism involved

presence / absence of complications

underlying patient characteristics

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What are the cardiac risk factors that can result in infective endocarditis

Native valve disease

Congenital heart disease  
   tetralogy of fallot 
  Ventral septal defect
  Patent ductus arteriosus 
  ASD - coarctation of aorta

Rheumatic heart disease

Prosthetic heart valve surgery

cardiac surgery

prior native IE

Cardia hypertrophy

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What is the non cardiac risk factors for IE

IVDA

immunocompromised eg elderly/AIDS

diabetes mellitus

AIDS

trauma (burns)

indwelling medial devises

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What is the different mode of acquisition in bacteraemia IE

Health care related e.g.
Hospital, health care contact, IV therapy, nursing home

community acquired

IV drug abuse

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What is the signs of IE

Murmur
Muscoskeletal pain

splinter haemorrhages 
vasculitic rash
Roth Spots 
Osler’s nodes 
Janeway lesions
nephritis
anemia

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What is the symptoms of IE

Fever
fatigue
malaise 
Weight loss 
Headache

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What are features of patients with a high Index of suspicion of diagnosis of IE

fever

new murmur

pyrexia of unknown origin

known IE causative organism

prosthetic material

previous IE

congenital heart disease

new conduction disorder

immunocompromised

IV drug abuser

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When could signs of IE be absent

elderly

when prior antibiotic treatment has been given before IE was considered

immunocompromised

IE involving less virulent / atypical organisms

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What are the investigations for Infective endocarditis

Blood tests: 
 FBC - full blood count 
(neutrophilia)
CRP - C-reactive protein
ESR - erythrocyte sedimentation rate
Urea &amp; electrolytes

Blood cultures
urinalysis

ECG

CXR

Echo

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What does the urea and electrolytes (blood test)indicate for in diagnosis of IE

nephritis
infection
sepsis

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What does ECG show in IE

conducting delay - due to abscess sitting on atrial ventricular septa

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What does a chest x ray show in infective endocarditis

Heart failure

Pulmonary abscesses

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What is the two types of echocardiogram

transthoracic (TTE)

+ transoesophageal (TOE

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When would you perform both atransthoracic (TTE)

+ transoesophageal (TOE)

When you have high clinical suspicion of infective endocarditis

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When would you perform a TOE

If TTE is positive:
To see complications and assesses
Measure size of vegetation

Poor quality TTE

Prosthetic valve intracardiac device present

If initial TOE negative but still have high clinical suspicion perform again within 7-10days

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When would you repeat an ECG in EI

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If new complication arrises

To asses ongoing treatment

To asses treatment success on completion

What could be the possible reasons of Infective endocarditis having a negative blood culture

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Prior antibiotic treatment

Fastidious organism - only grow with specific nutrients

Intracellular bacteria

Organisms can cause what types of IE

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Native valve IE
IVDA IE
Prosthetic valve IE

What is the pathogenesis of IE

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damage to the endothelium with invasion and adherence of micro-organism to injured surface, proliferation then breaking of causing thrombotic endocarditis
= a sterile fibrin-platelet vegetation (abnormal mass)

What is the organisms responsible for IE

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Staphylococcus aureas - most common

Strepococci (Strep. Viridans)

Pseudomonase

aerguginosa

HACEK organisms

Fungi

Enterococci

How do you test for the intracellular bacteria causing IE

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serological testing, cell culture,
gene amplification,
PCR

What is the major factors modified duke criteria for IE

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Blood culture of IE positive
- + with 2 separate culture/ persistent

Evidence of endocardial involvement

- ECG
Valve murmur

What is the minor factors in modified duke criteria

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Predisposition
- heart condition/ drug use

fever

vascular/immunologic phenomena

Microbiological evidence
+ blood culture / serological evidence

What is the criteria must be met from modified duke criteria for a definite diagnosis

2 major 1 major + 3 minor 5 minor

What is the treatments for IE

Antibiotics - IV Aminoglycosides best = bactericidal with shortened duration therapy Surgery

What does your choice of antibiotic depend upon

Received previous antibiotics if its either native or prosthetic valve When valve surgery was performed local epidemiology antibiotic resistance specific culture negative pathogens

What therapy is needed for slow growing dormant microbes

Prolonged antibiotic therapy eg 6 weeks + + removal of prosthetic material

What is the antibiotic treatment of native valve IE

IV Gentamicin 1mg/kg 12 hourly + IV Amoxycillin 2g 4 hourly {or vancomycin if if penicillin allergic, severe sepsis or MRSA}

What is the antibiotic treatment for prosthetic valve IE

``` Gentamicin + IV Vancomycin + Rifampicin ```

What is the disadvantages of Gentamicin

nephrotoxic ototoxic dose must be measured to actual body weight

What is the monitoring treatment with IE

blood tests daily ECG every 1-2days ECHO weekly

What is the complications of IE

heart failure fistula formation leaflet perforation uncontrolled infection abscess formation atrioventricular heart block embolism prosthetic valve dysfunction /dehiscence

What is the most frequent and severe complication of IE, how is it shown

Heart failure - shown by refractory pulmonary oedema

How do you know the in infection is uncontrolled

Persisting fever and positive blood cultures

What is the cause of an uncontrolled infection

Inadequate antibiotic treatment resistant organisms Infected lines extracardaic site of infection adverse reaction to antibiotics

How does abscess formation result in | atrioventricular heart block

If abscess in close proximity to base of septum innervates bundle of HIS and prevents conduction in the heart

what is most likely to cause embolism in IE

Previous embolism Multi-vascular IE The size and mobility of vegetation Increasing the antibiotic

What is the most severe IE

prosthetic valve endocarditis

What is the therapy for prosthetic valve endocarditis

removal recommended | and prolonged IV antibiotic course

What is examples of prophylaxis

avoid extensive non-evidence-based use of antibiotics Maintain good oral dental hygiene

infective endocarditis Flashcards

(41 cards)