Infective Endocarditis

Question 1

What is infective endocarditis?

Answer 1

Infection of the endocardium (inner lining of heart, mainly valves)

Question 2

List the 3 main causative organisms of infective endocarditis

Answer 2

Streptococci: A-haemolytic S. viridans + S. bovis
Staphylococci: S. aureus + S. epidermidis
Enterococci: E. faecalis

Question 3

Describe the pathophysiology in infective endocarditis

Answer 3

Vegetations form when organisms deposit on valves during a period of bacteraemia
Vegetations composed of platelets, fibrin + infective organisms
Destroy valve leaflets, invade myocardium/ aortic wall leading to abscess cavities

Question 4

List 7 symptoms of infective endocarditis

Answer 4

Fever/ chills/ rigors
FLAWS
Myalgias
Weakness
Arthralgias
Chest pain 
Back pain

Question 5

Describe the epidemiology of infective endocarditis

Answer 5

2-6 per 100,000

Question 6

List 5 signs on general examination in infective endocarditis

Answer 6

Clubbing
Pyrexia  
Tachycardia  
Signs of anaemia 
Splenomegaly

Question 7

What may be heard on auscultation in infective endocarditis?

Answer 7

New regurgitant murmur or muffled heart sounds
Frequency of heart murmurs:
Mitral > Aortic > Tricuspid > Pulmonary

Question 8

What vasculitic lesions may be seen in infective endocarditis?

Answer 8

Roth spots on retina
Petechiae on pharyngeal + conjunctival mucosa
Janeway lesions (painless macules on palms which blanch on pressure)
Osler’s nodes (tender)
Splinter haemorrhages

Question 9

What blood investigations are appropriate in infective endocarditis?

Answer 9

FBC: leukocytosis, normocytic anaemia 
High ESR/CRP  
U+Es: normal/ elevated
Blood culture: MC+S
Many pts are rheumatoid factor positive

Question 10

What bedside investigations are appropriate in infective endocarditis? What may be found?

Answer 10

ECG: prolonged PR interval, non-specific ST/T wave abnormalities, AV block
Urine dipstick: RBC casts, WBC casts, Proteinuria, Pyuria

Question 11

What imaging investigations are appropriate in infective endocarditis? What will be seen?

Answer 11

Echocardiography

Valvular, mobile vegetations

Question 12

What system is used for diagnosing infective endocarditis based on the findings of the investigations + the symptoms/signs?

Answer 12

Dukes Classification

Question 13

What is the management plan in suspected/ streptococci infective endocarditis?

Answer 13

Benzylpenicillin

Gentamicin

Question 14

What is the management plan in staphylococci, enterococci and culture negative infective endocarditis?

Answer 14

Staphylococci: Flucloxacillin/ Vancomycin + Gentamicin
Enterococci: Amoxicillin + Gentamicin
Culture Negative: Vancomycin + Gentamicin

Question 15

When may surgical treatment be needed in infective endocarditis?

Answer 15

Urgent valve replacement may be needed if poor response to Abx

Question 16

List 7 complications of infective endocarditis

Answer 16

CHF
MI
Heart valve insufficiency.
Valvlar dehiscence, rupture or fistula
Splenic abscess
Glomerulonephritis
Arterial emboli, infarctions, mycotic aneurysms.

Question 17

What is the prognosis in infective endocarditis?

Answer 17

FATAL if untreated

15-30% mortality even WITH treatment

Question 18

Which valve is most commonly affected in IV drug users? Which organism is most common?

Answer 18

Tricuspid valve

S aureus

Question 19

List 5 cardiac risk factors for infective endocarditis

Answer 19

Abnormal valves (e.g. congenital, calcification, rheumatic heart disease)
Prosthetic heart valves
Pacemaker
Turbulent blood flow (e.g. patent ductus arteriosus)
Previous endocarditis

Question 20

List 4 non-cardiac risk factors for infective endocarditis

Answer 20

IV drug use
Recent dental work/ poor dental hygiene (S. viridans)
IV catheter
Immunosuppression