Infective Endocarditis

Question 1

What is infective endocarditis?

Answer 1

It is the infection of the endocardial surface of the heart involving the heart valves +/- Mural endocardium +/- septal defect

Question 2

What are the 4 main complications of infective endocarditits?

Answer 2

Valvular failure
Heart failure
Sepsis
Embolic disease

Question 3

One of the major complications of IE is embolic disease. What could this lead to?

Answer 3

Stroke, MI, mycotic aneurysm, AKI, Liver injury, distal embolus (blue toe syndrome)

Question 4

What side of the heart is more affected in IE?
Which valve is most effected?

Answer 4

Left side > Right side (95% are left sided)
Mitral > Aortic valves

Question 5

Explain the pathophysiology of infective endocarditis

Answer 5

The endocardial surface or valves become infected after exposure to microemboli from bacteria or fungi circulating in the blood stream. Previously damaged tissue (previous IE, surgery) or non-native valves predispose to this infection

These organisms proliferate in the evolving thrombus + Persistent shedding into the blood stream causes an immune response resulting in symptoms

Vegetations in the valves causes valvular destruction and failure

Question 6

What are the RFs for infective endocarditis?

Answer 6

Patient factors:
Age>60
Immunocompromised (DM, chemo, splenectomy, sickle cell, transplant, HIV)

Pathology:
Congenital/Structural heart disease
Valvular heart disease
Previous IE
Bowel Cancer

Procedure:
IVDU
Surgical procedure (valvular replacement, stent, and even if not cardiac)
Termination of pregnancy
Haemodialysis
Failure of aseptic technique

Question 7

What is the most common organism causing IE?

What is the most common organism causing IE in Prosthetic valves?

What is the most common organism causing subacute IE?

What is the most common organism causing IE in a patient with lower GI/GU disease and bowel malignancy?

Answer 7

Staph aureus is the most common

Strep epidermidis and aureus are most common in prosthetic valves

Strep viridans is most common in subacute disease

Enterococci (Faecalis and Faecium) for GI/GU disease and bowel malignancy

Question 8

What are the organisms that are most likely involved in IE?

Answer 8

Staph aureus is the most common

Strep epidermidis and aureus are most common in prosthetic valves

Strep viridans is most common in subacute disease

Enterococci (Faecalis and Faecium) for GI/GU disease and bowel malignancy

Coxiella (needs only 1 positive culture)

Fungi in immunocompromised patients

HACEK group in 2% of cases

Question 9

What murmurs are most a/w IE?

Answer 9

AR or MR are most associated with IE (remember left sided and vegetations)

Question 10

Are Osler nodes painful or painless?
Where are they typically located?

Answer 10

Painful and palm, pads of fingers and toes

Question 11

Are Janeway lesions painful or painless?
Where are they typically located?

Answer 11

Painless (and haemorrhagic) on the palms of hand and soles of foot

Question 12

Go through the signs and symptoms of IE

Answer 12

Symptoms: Fever, night sweats, anorexia, weight loss, Myalgia
In advanced disease, HF: SOB/dyspnoea, PND, orthopnoea, chest pain, cough with pink, frothy sputum

Signs: FROM JANE

Fever
Roth Spots
Osler Nodes
(New) Murmur - typically left sided

Janeway lesions
Anaemia
Nailbelt haemorrhages
Embolic (Stroke, MI, mycotic aneurysm, AKI, Liver injury, distal embolus)

+ clubbing, poor dentition, and scars of previous cardiac surgery on closer inspection

+ Splenomegaly on palpation (mild)

Question 13

What are the major criteria in Duke’s criteria?

Answer 13

Major:
a) Blood cultures: 2 separate cultures of typical organisms
or 1 culture of coxiella

b) Imaging:
TOE ECHO 2V2A: showing vegetations or valvular perforation or Abscess or Aneurysm/pseudoaneurysm

Cardiac CT: Paravalvular lesions

PET CT FDG: Abnormal activity around prosthetic valve

Question 14

What are the minor criteria in Duke’s criteria?

Answer 14

Minor Criteria:

a) Fever >38
b) Microbiology evidence but inadequate for major
c) Predisposing factors (tissue damage, previous IE…)
d) Vascular phenomena (emboli/thrombosis)
e) Immunological phenomenon (osler’s, Janeway lesions, Glomerulonephritis)

Question 15

What is required for a Definite IE dx vs probable?

Answer 15

Definite if:
a) Pathological evidence on histology of vegetations or intracardiac abscess
b) 2 major criteria
c) 1 major + 3 minor
d) all 5 minor

Probable if:
a) 1 major + 1 minor
b) 3 minor

Question 16

Fully explain Duke’s criteria in the diagnosis of IE

Answer 16

Definite if:
a) Pathological evidence on histology of vegetation or intracardiac abscess
b) 2 major criteria
c) 1 major + 3 minor
d) all 5 minor

Probable if:
a) 1 major + 1 minor
b) 3 minor

Major Criteria:
a) Blood cultures: 2 separate cultures of typical organisms
or 1 culture of coxiella

b) Imaging:
TOE ECHO 2V2A: showing vegetations or valvular perforation or Abscess or Aneurysm/pseudoaneurysm

Cardiac CT: Paravalvular lesions

PET CT FDG: Abnormal activity around prosthetic valve

Minor Criteria:

a) Fever >38
b) Microbiology evidence but inadequate for major
c) Predisposing factors (tissue damage, previous IE…)
d) Vascular phenomena (emboli/thrombosis)
e) Immunological phenomenon (osler’s, Janeway lesions, Glomerulonephritis)

Question 17

What investigations would you like to order if you are suspecting IE?

Answer 17

Bedside: ABG/VBG, ECG, Urine dipstick/urinalysis (source of sepsis and signs of kidney injury)

Bloods:
FBC -> Hb anaemia, raised WCC, low platelets in sepsis, DIC
CRP -> elevated
U&E -> AKI (end-organ failure from sepsis or emboli) + for medications or contrast
LFTs -> Liver injury due to emboli

Imaging:
ECHO (for valvular vegetation and perforation + abscess, aneurysm/pseudoaneurysm)
Cardiac CT (paravalvular lesions)
PET CT FDG (Abnormal activity around prosthetic valve)
+
CT/MRI brain for emboli and infarcts

Question 18

What echo will you use for IE?

Answer 18

Initially TTE the TOE. TOE required to visualise vegetations and or

Question 19

What will you find on urinalysis showing kidney disease? (not necessarily as a complication of IE)

Answer 19

Oliguria/anuria
Proteinuria
Haematuria
Casts (RCC, WCC, granular)

Question 20

What is the prophylactic antibiotic regimen given to patients at risk of IE? e.g. prosthetic valve, prior IE, heart defects, immunocompromised…

When is it indicated?

Answer 20

2g amoxicillin 30-60 minutes prior to
1) High risk dental procedures
2) Interventions on infected mucosa (Resp, GU, derm)

Question 21

What preventative measures can you advise the patient about (IE)?

Answer 21

1) Good dental hygeine
2) 2g amoxicillin 30-60 minutes prior to
1) High risk dental procedures
2) Interventions on infected mucosa (Resp, GU, derm)

Question 22

What is the antibiotic regimen for a native valve IE?

Answer 22

Native: 2-6 weeks IV
Subacute: amoxicillin/benzyl + Gentamicin
Acute or IVDU: Vancomycin + Gentamicin

Question 23

What is the antibiotic regimen for a prosthetic valve IE?

Answer 23

Prosthetic: >6 weeks IV
Vancomycin + Gentamicin + Rifampicin

Question 24

Half of those with IE will require surgical intervention.

What are the absolute indications for surgical management?

What is the surgical management of IE?

Answer 24

Severe aortic or mitral regurg.
Atrial or Mitral Vegetations >10mm after 1 embolic episode
Atrial or Mitral Vegetations > 15mm regardless
Uncontrolled infection despite AB

Surgical repair involving valve repair, reconstruction, replacement (nothing specific)

Question 25

What is the subacute/acute management for IE?

Answer 25

Pharmacological:
Prolonged antimicrobrial therapy (2-6 weeks in native valve and >6 weeks in prosthetic valve) according to antimicrobial guidelines

Native: 2-6 weeks IV
Subacute: amoxicillin/benzyl + Gentamicin
Acute or IVDU: Vancomycin + Gentamicin

Prosthetic: >6 weeks IV
Vancomycin + Gentamicin + Rifampicin

Surgical repair involving valve repair, reconstruction, replacement

Question 26

What is the chronic management of IE?

Answer 26

1) Good dental hygeine
2) 2g amoxicillin 30-60 minutes prior to
1) High risk dental procedures
2) Interventions on infected mucosa (Resp, GU, derm)

Continuous antibiotic prophylaxis if required in high risk patients

Question 27

What are the complications of IE?

Answer 27

Cardiac:
HF
Re-infection
Aortic abscess causing AV block
Valvular failure

Non-Cardiac:
Embolism causing Stroke, Splenic infarct, distal ischaemia (blue toe), MI, Limb ischaemia, PE, mesenteri ischaemia…
AKI
Glomerulonephritis

Question 28

Embolism complicated up to 50% of cases decreasing to 20% post-AB therapy. It is associated with the size and mobility of vegetation. What period of time is the risk of embolism highest?

Answer 28

First 2 weeks