Infective Endocarditis

Question 1

Presentation of Breathlessness, Fever, and Heart murmurs. What are differentials ?

Answer 1

Infective endocarditis, Pericardial disease, Myocarditis, Sepsis

Question 2

What is infective endocarditis ?

Answer 2

Infection of the endothelium of the heart valves
-Life threatening - often diagnosed late
-Up to 25% mortality
-May be “acute” or “subacute”

Vegetations grown:

Question 3

What are predisposing factors to infective endocarditis ?

Answer 3

Heart valve abnormality
-Calcification/sclerosis in elderly
-congenital heart disease (e.g. bicuspid aortic valve)
-post rheumatic fever
Prosthetic heart valve
People who inject drugs
Intravascular lines

Question 4

How does endocarditis develop ?

Answer 4

1) Heart valve damaged
2) Turbulent blood flow over roughened endothelium
3) Platelets/fibrin deposited
4) Bacteraemia (may be very transient) e.g. from dental treatment in high- risk patients
5) Organisms settle in fibrin/platelet thrombi becoming a microbial vegetation

Question 5

Which side of the heart is more commonly affected by infective endocarditis ?

Answer 5

Left side of heart more commonly affected (mitral and aortic valves)
-In IV drug users right side more likely to be affected

Question 6

How can vegetations cause further issues ?

Answer 6

Infected vegetations are friable and break off, becoming lodged in the next capillary bed they encounter causing abscesses or haemorrhage - may be fatal. Lungs, brain etc.

Question 7

How does acute infective endocarditis present and what causes it ?

Answer 7

Presents as overwhelming sepsis and cardiac failure

Usually due to aggressive (virulent) organisms such as Staphylococcus aureus

Question 8

How does subacute infective endocarditis present and what causes it ?

Answer 8

Slow onset
Fever
Malaise
Weight loss
Tiredness
Breathlessness

Question 9

What are roth spots ?

Answer 9

Non-specific red spots seen on the retina
-caused by infective endocaridits

Question 10

What are Janeway lesions ?

Answer 10

Non-tender, small, erythematous or haemorrhagic or nodular lesions on the palm or sole caused by septic emboli
-Can be caused by infective endocarditis

Question 11

What are Osler nodes ?

Answer 11

Painful, red, raised lesions found on the palms or sole caused by immune complex deposition
-Can be caused by infective endocarditis

Question 12

How can a definitive infective endocarditis result be determined ?

Answer 12

Two major criteria, one major + three minor criteria, or all five minor criteria

Duke criteria

Question 13

What are the microbiology major criteria for infective endocarditis ?

Answer 13

> 2 separate sets of blood cultures with typical organisms isolated
3 separate sets of blood cultures with non-typical organisms
Laboratory tests (pcr or IgG

Causes sustainced positive blood cultures; 1+ and 1- means not IE

Question 14

What is bacteraemia ?

Answer 14

Blood is normally sterile, viable bacteria in the bloodstream cause bacteraemia
-Potentially life-threatening but not always significant
-If body’s response to infection is dysregulated and causes organ dysfunction, this is called sepsis

Used to be called septicaemia

Bacteria found in blood may not be the one causing any illness

Question 15

What should be done for suspected IE before confirming results are obtained ?

Answer 15

Empiric treatment; best-guess

Question 16

What is the difference between staph and streptococcus ?

Answer 16

Staphylococcus = Gram-positive cocci in clusters
Streptococcus = Gram positive cocci in chains

Gram positives are the big endocariditis ones

Question 17

How can different staphylococci be distinguished ?

Answer 17

Coagulase test distinguishes Staphylococcus aureus from Coagulase-negative staphylococci (like Staphylococci epidermidis)
-Coagulase negatives are rarely virulent and seldom need antibiotics unless complicating factors exist e.g. metal/plastic in body or sustained + results

Question 18

What is MALDI-TOF ?

Answer 18

Matrix Assisted Laser Desorption/Ionisation – Time Of Flight
-Alows for rapid organism identification and rapid determination of its susceptibility

Question 19

How should blood cultures be used in IE?

Answer 19

Take 3 sets of blood culture taken
-If all are positive there is good evidence of continuing bacteraemia.
-If only one set taken and is positive might be a contaminant.
-Should be taken before any antibiotics
-If blood cultures negative, consider serology for additional organisms

(Sets taken over 30-60 mins)

Contaminant = bacteria added to sample during extraction; error

Question 20

What are common bacteria causing native valve IE ?

Answer 20

Question 21

What are unusual organisms which can cause IE ?

Answer 21

Not usually cultured organisms (PCR used)
-Bartonella, Coxiella burnetii (Q-fever), Chlamydia, Legionella, Mycoplasma, Brucella

Gram-negatives
-HACEK organisms; Haemophilus spp. , Aggregatibacter spp , Cardiobacterium, Eikenella sp., Kingella sp.
-Non HACEK gram negatives
-Hard to grow

Fungi
-Hard to treat here

Question 22

What are examples of gram positive bacteria which cause IE ?

Answer 22

Staph A
Staph Epidermis
Viridans Group Streptococci

Question 23

What is staph epidermis ?

Answer 23

Often a skin contaminant, but can infect prosthetic material e.g. ICED, prosthetic heart valves/joints, lines
-Most common coagulase-negative staphylococci
-Take more than one set of blood cultures to confirm significance

Question 24

What are signs of subacute IE ?

Answer 24

Fever
New or changing heart murmur
Finger clubbing
Splinter haemorrhages
Splenomegaly
Roth spots, Janeway lesions, Osler nodes
Microscopic haematuria

Question 25

What are viridans group strep ?

Answer 25

Cause Subacute endocarditis -Alpha haemolytic strep (partial breakdown, gree-Alpha haemolytic strep (partial breakdown, green colour)n colour) -Normal oral commensals; brushing teeth moves bactera into blood so poor dentition and prosthetics are a risk

Question 26

What is prosthetic valve endocarditis and its types ?

Answer 26

Early (within 60 days) and late presentations Early- usually infected at time of valve insertion and usually due to Staphylococcus epidermidis or Staphylococcus aureus Late - up to many years after valve insertion - due to co-incidental bacteraemia. Wide range of possible organisms

Question 27

What is endocarditis in intravenous drug users like ?

Answer 27

Right-sided endocarditis (tricuspid >mitral > aortic) -Usually Staphylococcus aureus -Suspect in Staphylococcus aureus plus septic pulmonary emboli | If tricuspid vegetations can break off and go into lungs

Question 28

What is the empiric treatment of native valve infection by viridans strep ?

Answer 28

Amoxicillin +/- synergistic gentamicin IV

Question 29

What is the empiric treatment of prosthetic valve infection ?

Answer 29

-Vancomycin +/- gentamicin IV -Add in day 3 to 5 (delayed) rifampicin PO -Often valve replacement is required

Question 30

What is the empiric treatment of IE in intravenous drug users (MSSA) ?

Answer 30

Flucloxacillin IV

Question 31

What drug is used for Staph A ?

Answer 31

Flucloxacillin IV -If MRSA treat as per prosthetic valve

Question 32

What drugs are used for viridans group strep ?

Answer 32

Benzylpenicillin iv & gentamicin iv (synergistic)*

Question 33

What drugs are used for Enterococcus sp. ?

Answer 33

Amoxicillin/ vancomycin + gentamicin IV*

Question 34

What drugs are used for ? Staphylococcus epidermidis

Answer 34

Vancomycin & gentamicin IV* & rifampicin PO

Question 35

What are risk factors for Implanatable cardiac electric devices ? (ICED)

Answer 35

Pre procedure prophylaxis errors Complexity of procedure Temporary pacer use Type of device Number of revisions / reinterventions Fever within 24 hours Heart failure, renal failure Haematoma post procedure

Question 36

What is myocarditis ?

Answer 36

More common in young people (cause of sudden death) Symptoms -fever, chest pain, shortness of breath, palpitations Signs -arrhythmia, cardiac failure Diagnosed by viral PCR. Throat swab and stool for enteroviruses. Throat swab for influenza Supportive treatment

Question 37

What are causes of myocarditis ?

Answer 37

Mainly caused by enteroviruses -Coxsackie A & B, echovirus, but other viruses possible the list is extensive. COVID-19 infection | Mainly viral cause

Question 38

What is pericarditis ?

Answer 38

Often occurs with myocarditis Chest pain main feature Viral aetiology mainly, Supportive treatment bacteria less common e.g post cardiothoracic surgery, rarely secondary spread from endocarditis or pneumonia treatment : antibiotics & drainage