Infective Endocarditis Flashcards
Definition
Infection of endocardium due to:
- causative bacteria
- colonising bacterial endothelium (causing vegetations)
Epidemiology
Men
Risk Factors
Male, Elderly, Prosthetic valves
Young IV drug user
Young Px with congenital heart defect
Rheumatic fever
Skin breaches (dermatitis, lines, wounds)
Renal failure
Aetiology
Bacterial:
- Strep viridans ( = gram + alpha haemolytic optochin resistant strep, associated with POOR DENTAL HYGIENE = Lower virulence, symptoms onset = weeks-months = SUBACUTE
- Staph aureus (most common in IV drug users, T2DM, surgery) = Increased virulence. Symptoms onset = days to weeks = ACUTE
- S. Bovis (associated with colon cancer
- P. Aeruginosa
Rare bacterial causes of IE (HACEK)
Gram negative bacteria
- Haemophilus Influenzae
- Actinobacillus
- Cardio bacterium
- Eikenella
- Kingella
Which valve is most commonly effected in IE
IE typically effects MITRAL VALVE (LSide)
BUT IN IV Drug users = TRICUSPID VALVE (RHS AV VALVE)
Pathophysiology
Abnormal/damaged endocardium have increased platelet deposition, bacteria adheres to this + causes vegetations
- typically, around valves
- causing regurgitation (aortic + mitral insufficiency = increased risk of HF)
Assume infective endocarditis when Px presents with…
Fever + new murmur = Assume infective endocarditis unless told otherwise
Any fever > 1 week in those at risk = prompt blood cultures
Signs
SIGNS TO LOOK OUT FOR:
- Embolic skin lesions
- Petechiae
- Splinter haemorrhages = on fingernails
- Osler nodes - bacterial Ag-Ab complex = finger nodules
- Janeway lesions = septic emboli = painful marks on hands
- Roth spots = bacterial Ag-Ab complex - retinal haemorrhage
Microscopic haematuria = common
Septic signs (Fever, rigors, night sweats, malaise, weight loss, anaemia, splenomegaly, clubbing)
Glomerulonephritis + AKI
Brain embolization = embolic stroke or intracerebral haemorrhage
Symptoms
Fever or chills
Headache
SOB
Night sweats, malaise, fatigue,
Wt loss
Joint pain maybe due to septic emboli
Diagnosis
Fever + new murmur - infective endocarditis until proven otherwise
FIRST LINE = TTE (if negative do TOE)
GOLD STANDARD = 3 cultures from 3 different spots at peak points of fever
= Aerobic
= Anaerobic
= Fungi
Bloods =
- normocytic, normochromic anaemia
- high ESR. CRP
- Neutrophilia
CXR = Cardiomegaly, pulmonary oedema
TOE = done in patients with
- prosthetic valves
- implantable cardiac device
- obese
- chest wall abnormalities
ECG - prolonged PR interval
Dukes’ criteria
2 Major or 1 Major + 2 Minor
Major
- 2 < +ve blood cultures
- ECHO, TOE shows vegetations
Minor
- Predisposing heart condition or IVDU
- Immunological signs (Glomerulonephritis, Osler nodes, Roth spots, Rheumatoid factor)
- Vascular abnormalities (septic emboli, arterial emboli, ICH, pulmonary infarct)
- 1 +ve blood test
- Hyperpyrexia 38 degrees
Treatment
Stable patient can start antibiotic therapy AFTER detaining blood cultures
If patient unwell (septic) = dont wait for blood cultures
STAPH + NATIVE VALVE = FLUCLOXACILLIN = Beta lactam or VANCOMYCIN if MRSA
STAPH + PROSTHETIC VALVE = FLUCLOXACILLIN + RIFAMPICIN + GENTAMYCIN
STREP = BENZYLPENECILLINS + GENTEMYCIN - 4-6 weeks
ENTEROCOCCI = AMOXICILLIN + GENTEMYCIN
Surgery -> remove valve if incompetent + replace with prosthetic
Complications
Heart Failure
Aortic root abscess
Septic emboli
SEPSIS
