Infective Endocarditis

Question 1

Abx prophylaxis indications:

ref: LIFTL

Answer 1

must have high risk patient AND high risk surgery

high risk patients:

1. any prosthetic material in used in valve repair
2. previous infectious endocarditis
3. congenital heart disease (unrepaired cyanotic, partially repaired, or completely repaired <6 months previously)
4. cardiac transplant patients with valvulopathy
5. ATSI population with rheumatic heart disease

high risk surgery
1. all dental procedures that involve manipulation of gingival tissue or periapical region of teeth or perforation of oral mucosa
— thus only check ups and simple fillings that don’t involve gingiva don’t need antibiotic prophylaxis
2. respiratory tract surgery
— incision and biopsy, tonsillectomy, adenoidectomy

Question 2

1/What is infective endocarditis?
2/Which valve does it commonly effect?

(ref: LIFTL)

Answer 2

1/Inflammation of the endocardium, typically affecting the heart valves, infection can be be acute, subacute or chronic
2/ aortic valve

Question 3

Risk factors for Endocarditis
(ref: LIFTL)
50% occur in normal valves

Answer 3

1/ Cardiac lesions
congenital heart disease
rheumatic heart disease
mitral valve prolapse
valve regurgitation
degenerative valve disease
prosthetic valve (1-5%) – early (<60 days) or late (>60 days)

2/ Predisposition to infection
IV drug use – tricuspid, aortic and mitral valve
haemodialysis
high risk surgery (e.g. dental, respiratory and infective)
long lines
bone marrow transplant recipients
immunosuppressed (e.g. HIV)

Question 4

How may a patient present?

Answer 4

— asymptomatic
— malaise, night sweats, anaemia, weight loss
— crashing cardiogenic shock and sepsis

haematuria (glomerulonephritis)

embolic complications
— stroke (esp if PFO), intracranial haemorrhage
— septic pulmonary emboli
— splenic infarction

(ref: LIFTL)

Question 5

Examination findings

Answer 5

Skin rash
Splinter haemorrhages and conjunctival haemorrhages
Oslers nodes – tender nodules on pulps of fingers and toes
Janeway lesions – non-tender haemorrhagic pulps on fingers and toes
Roth spots – retinal hemorrhages with a pale centre
Splenomegaly
New neurological signs
New murmur, e.g. aortic regurgitation and associated systemic features
Left ventricular failure – basal crackles and effusions
Emboli — major arteries, pulmonary, spleen
Haematuria

Question 6

Investigations

Answer 6

ECG: look for widening PR interval, p mitrale, TWI, dysrhythmia

Laboratory
Blood cultures (90% of the time positive)
— need at least 2 sets drawn 12 hours apart, or
— minimum of 3 out 4 sets postive with first and last positive set >1 hour apart
Serology for causative organisms
Rheumatoid factor
PCR for microbial 16S ribosomal RNA genes from valve tissue (if culture negative)

ECHO
TTE = 60% sensitive, TOE = 90-99% sensitive, specificity of 90%

(ref: LIFTL)

Question 7

Criteria for diagnosis

Answer 7

Modified Duke Criteria

ref: LIFTL

Question 8

COMPLICATIONS

Answer 8

embolic (major arteries, brain, limbs, lungs, organs such as spleen)

sepsis (local and metastatic abscess formation)

valve incompetence and heart failure / cardiogenic

shock

arrhythmias
death

(ref: LIFTL)

Question 9

Organism causes

Answer 9

Staphylococcus aureus (MSSA or MRSA)
Coagulase negative Staphylococci: S. epidermidis, S. lugdenensis 
Streptococcus viridans
Streptococcus bovis
Enterococcus
HACEK organisms
-> Haemophillus aphrophilus, parainfluenzae and paraphrophilus
-> Actinobacillus actinomycetemcomitans
-> Cardiobacterium hominis
-> Eikenella corrodens
-> Kingella kingae

Fungi

Culture negative endocarditis
Brucella
Bartonella
Coxiella burnetti (Q fever)
Chlamydia
Legionella
Mycoplasma
Whipples disease (Trophyerma whipplei)

(ref: LIFTL)