Infective Endocarditis

Question 1

Define Infective Endocarditis?

Answer 1

Infection of intracardiac endocardial structures (mainly heart valves)

Question 2

What are the most common organisms causing Infective Endocarditis?

Answer 2

Streptococci (40%) - mainly a-haemolytic S.viridans and S. bovis
Staphylococci (35%) - S. aureus and S. epidermidis
Enterococci (20%) - usually E. faecalis

Question 3

What are the other organisms that can cause Infective Endocarditis?

Answer 3

Haemophilus 
Actinobacillus 
Cardiobacterium
Coxiella Burnetii 
Histoplasma (fungal)

Question 4

What is the pathophysiology of Infective Endocarditis?

Answer 4

Vegetations form when organisms deposit on the heart valves during a period of bacteraemia
The vegetations are made up of platelets, fibrin and infective organisms
They destroy valve leaflets, invade the myocardium or aortic wall leading to abscess cavities
Activation of the immune system can lead to the formation of immune complexes leads to vasculitis, glomerulonephritis, arthritis

Question 5

What are the risk factors for Infective Endocarditis?

Answer 5

Abnormal valve (e.g. congenital, calcification, rheumatic heart disease)
Prosthetic Heart valves
Turbulent blood flow (e.g. patent ductus arteriosus)
Recent dental work/poor dental hygeine (source of S. viridans)

Question 6

What is the epidemiology of Infective Endocarditis?

Answer 6

UK Incidence: 16-22/1 million per year

Question 7

What are the presenting symptoms of Infective Endocarditis?

Answer 7

Fever with sweats/chills/rigors (may be relapsing and remitting)
Malaise 
Arthralgia
Myalgia 
Confusion
Skin Lesions

Question 8

What do we have to remember to ask with Infective Endocarditis?

Answer 8

Ask about recent dental surgery or IV drug use

Question 9

What are the signs of Infective Endocarditis on physical examination?

Answer 9

Pyrexia 
Tachycardia
Signs of Anaemia 
Clubbing 
New regurgitant murmur or muffled heart sounds 
Frequency of heart murmurs: Mitral > Aortic > Tricuspid > Pulmonary
Splenomegaly
Vasculitis Lesions

Question 10

What are the more specific signs of Vasculitic lesions in Infective Endocarditis?

Answer 10

Roth spots on retina
Petechiae on phayrngeal and conjuctival mucosa
Janeway lesions (painless macules on the palms which blanch on pressure)
Osler’s nodes (tender nodules on finger/toe pads)
Splinter haemorrhages

Question 11

What bloods would you do for Infective Endocarditis?

Answer 11

FBC -high neutrophils, normocytic anaemia
High ESR/CRP
U&Es

Question 12

What do patients with Infective Endocarditis tend to have in bloods?

Answer 12

Tend to be rheumatoid factor positive

Question 13

Why do we do a Urinalysis for Infective Endocarditis?

Answer 13

Microscopic Haematuria

Proteinuria

Question 14

What do we do alongside a blood culture for Infective Endocarditis?

Answer 14

Do microscopy and sensitivies as well

Question 15

What echocardiography do we do for Infective Endocarditis?

Answer 15

Transthoracic or transoesophageal (produces better image)

Question 16

What is the Duke’s Classification for Infective Endocarditis?

Answer 16

A method of diagnosing Infective Endocarditis based on the findings of the investigations and the symptoms/signs

Question 17

What is the management plan for Infective Endocarditis?

Answer 17

Antibiotics for 4-6 weeks

Question 18

What is the empiracal treatment/ What antibiotics do we give for clinically suspected Infective Endocarditis?

Answer 18

Benzylpenicillin

Gentamycin

Question 19

What antibiotics do we give for Streptococci caused Infective Endocarditis?

Answer 19

Same as empirical treatment (Benzylpenicllin and Gentamycin)

Question 20

What antibiotics do we give for Staphylococci-caused Infective Endocarditis?

Answer 20

Flucloxacillin/vancomycin

Gentamicin

Question 21

What antibiotics do we give for Enterococci-caused Infective Endocarditis?

Answer 21

Ampicillin

Gentamycin

Question 22

What antibiotics do we give for Culture-negative Infective Endocarditis?

Answer 22

Vancomycin

Gentamycin

Question 23

What surgery can we do for Infective Endocarditis?

Answer 23

Urgent Valve Replacement may be needed if there is a poor response to antibiotics

Question 24

What are the possible complications of Infective Endocarditis?

Answer 24

Valve incompetence 
Intracardiac fistulae or abscesses 
Aneurysm 
Heart Failure 
Renal Failure 
Glomerulonephritis 
Arterial emboli from the vegatations shooting to the brain, kidneys, lungs and spleen