Infective Endocarditis

Question 1

Infective endocarditis

Answer 1

Infection involving the endocardial surface

Question 2

What other structures can it effect (4)

Answer 2

• Valvular structures- native and prosthetic valve
• Chordae Tendineae
• Sites of septal defects
• Mural endocardium

Question 3

Incidence

Answer 3

More common in men

Worse prognosis in women

Question 4

MDT (6)

Answer 4

• Referring doctors/GPs
• Microbiologists/Infectious disease team
• Cardiothoracic surgeon
• Radiologists
• Neurologists/Neurosurgeon
• Reference centre- complicated cases

Question 5

Evolving epidemiological profile

Answer 5

• Past- young adults (chronic/subacute course)
• Present- older patients with degenerative heart disease, healthcare associated procedure, valve diseases, congenital heart disease, prosthetic valve, IVDU, Immunocompromised patients

Question 6

Risk factors for Native IE (9)

Answer 6

• Mitral valve disease
• Rheumatic heart disease
• Congenital heart disease
• Degenerative heart disease
• Asymmetrical septal hypertrophy
• IV drug abusers
• Alcoholic cirrhosis
• Diabetes mellitus
• Indwelling medical devices

Question 7

Pathophysiology of IE in the valve endothelium (4)

Answer 7

Mechanical disruption exposes EM
Produces tissue factors
Deposition of fibrin and platelets
NBTE facilitates adherence and infection

Question 8

Causes of damaged endothelial valve (5)

Answer 8

• Turbulent blood flow (venturi effect-low pressure)
• Electrodes
• Catheters
• Inflammation (rheumatoid carditis)
• Degenerative valve disease

Question 9

Venturi Effect

Answer 9

• Reduction in fluid pressure when a fluid flows through constricted area of pipe
• High velocity and low pressure

Question 10

Pathophysiology of endothelial Inflammation (3)

Answer 10

• Inflammation leads to expression of integrins (B1 family)
• Integrin acts like a hook that binds circulating fibronectin on staph aureus
• Adherent organisms trigger active internalisation into valve endothelial cells

Question 11

Causes of Bacteraemia

Answer 11

Invasive procedures
Extra cardiac infections
Non invasive activities

Question 12

Name 6 Causative organisms of IE

Answer 12

• Viridans group streptococci
• Staphylococcus aureus
• Enterococci
• Coagulase-negative staphylococci
• Streptococcus bovis
• Fungi

Question 13

Classification of IE (6)

Answer 13

• Acute- days/weeks
• Subacute- weeks/months
• Nidus- localisation
• Mode of acquisition
• Active
• Recurrence

Question 14

Localisation (2)

Answer 14

Left or Right sided

Native or Prosthetic valve

Question 15

Mode of acquisition (4)

Answer 15

Nosocomical
Non Nosocomical
Community acquired
IV drug abuse

Question 16

Active IE (4)

Answer 16

Persistent fever and positive blood cultures
Active inflammatory morphology
Histopathological evidence
Histopathological evidence of active IE

Question 17

Recurrence

Answer 17

Relapse
Reinfection
less than 6 months since the last episode

Question 18

Diagnosis (5)

Answer 18

• High index of suspicion
• Bacteraemia with audible murmur should raise suspicion
• Elderly or immunocompromised
• Acutely- fever, embolic signs/symptoms or decompensated HF
• Subacute fever, non-specific constitutional symptoms or palpitation

Question 19

Common symptoms (6)

Answer 19

• Fever/chills
• Night sweats, malaise, fatigue, anorexia, weight loss
• Weakness
• Arthralgia
• Headache
• SOB

Question 20

Clinical signs (10)

Answer 20

• Cardiac murmur (regurgitant murmur)- with signs of HF
• Janeway lesions
• Petechial haemorrhage
• Osler nodes
• Roth spot- retinal haemorrhage
• Meningeal signs
• Splinter haemorrhage
• Cutaneous infarcts
• Vasculitic rash
• Immune complex deposition

Question 21

Investigations (8)

Answer 21

• Blood culture (3 sets and sites 30mins apart)
• FBC. ESR/CRP elevated acute inflammatory markers
• U+Es- renal failure
• Urinalysis for blood
• ECG- prolongation of PR interval >200ms
• CXR: pulmonary congestion or abscess
• MSCT, MRI, PET.CT and leucocyte SPECT/CT
• Transthoracic or transoesophageal echocardiography

Question 22

Modified Duke’s Criteriea (1)

Answer 22

1. Blood cultures positive for IE
   A. Typical micororganisms consistent with IE from 2 seperate blood culture
   B. Microorganisms consistent with II from persistently positive cultures
   C. single positive blood culture

Question 23

A. Typical micororganisms consistent with IE from 2 seperate blood culture

Answer 23

Viridans streptococci, Streptococcus gallolyticus (Streptococcus bovis), HACEK group,
• Staphylococcus aureus; OR
• Community-acquired enterococci, in the absence of a primary focus;

Question 24

C. single positive blood culture

Answer 24

Coxiella burnetii or phase I IgG antibody titre >1:800

Question 25

Modified Dukes Criteria (2)

Answer 25

Imaging positive for IE A. Vegetation B. Abnormal activity around the site of prosthetic valve C. Definite paravalvular lesions by cardiac CT

Question 26

A. Echocardiogram positive for IE:

Answer 26

* Vegetation * Abscess, pseudoaneurysm, intracardiac fistula •Valvular perforation or aneurysm * New partial dehiscence of prosthetic valve

Question 27

B. Abnormal activity around the site of prosthetic valve implantation

Answer 27

detected by 18F-FDG PET/CT (only if the prosthesis was implanted for >3 months) or radiolabelled leukocytes SPECT/CT.

Question 28

ESC 2015 Modified Duke’s Criteria- Minor Criteria (5)

Answer 28

1. Predisposition such as predisposing heart conditions or IV drug use 2. Fever defined as temperature above 38 3. Vascular phenomena 4. Immunological phenomena 5. Microbiological evidence

Question 29

Diagnosis of definite IE (3)

Answer 29

* 2 major * 1 major +3 minor * 5 minor

Question 30

Diagnosis of possible IE (2)

Answer 30

* 1 major + 1 minor | * 3 minors

Question 31

Rejection of the diagnosis of IE

Answer 31

• Resolution of endocarditis with antibiotic therapy

Question 32

What does the treatment depend on (3)

Answer 32

* Whether patient received previous antibiotic therapy * Whether infection affects native or prosthetic valve * The mode of infection

Question 33

Treatment for community acquired native or late prosthetic valves (3)

Answer 33

Ampicillin Flucloxacillin Gentamicin IV

Question 34

Treatment for community acquired native or late prosthetic valves with penicillin allergy

Answer 34

Vancomycin and Gentamicin IV

Question 35

Early PVE post surgery or noscomical or non-nosocomial (3)

Answer 35

Vancomycin Gentamicin Rifampin

Question 36

Patient characteristics that can cause complications (4)

Answer 36

Older age Prosthetic valve DM Comorbidity

Question 37

Clinical complications of IE

Answer 37

``` HD Renal failure Ischaemic stroke Brain Haemorrhage Septic shock ```

Question 38

Microorganism complications (3)

Answer 38

Staph aureus Fungi Non-HACEK gram negative bacilli

Question 39

ECHO findings (7)

Answer 39

``` Periannular complications Severe left-sided valve regurgitation Low left ventricular ejection fraction Pulmonary hypertension Large vegetation Valve dysfunction elevated systolic pressure ```

Question 40

Complications and Indications for Surgery (4)

Answer 40

* Heart failure in IE * Uncontrolled infection * Migration of cardiac vegetation to brain/spleen from left IE * Pulmonary embolisms are the result of right sided IE

Question 41

Principles of prevention of IE (3)

Answer 41

• Antibiotic prophylaxis must be limited with patients with the highest risk of IE  Patients with prosthetic valves  Previous IE  Congenital heart disease • Good oral hygiene and regular dental review are more important than antibiotic prophylaxis to reduce the risk • Aseptic measures

Question 42

Preventative measures (7)

Answer 42

* Strict dental hygiene * Disinfection of wounds * Curative antibiotics * No self-medication with antibiotics * Strict infection control * Discourage piercing and tattooing * Limit the use of infusion catheters and invasive procedures