Infective Endocarditis

Question 1

What is infective endocarditis?

Answer 1

Inflammation of the inner tissues of the heart, especially the heart valves

Caused by infectious agents

Question 2

What two symptoms are said to indicate endocarditis until proven otherwise?

Answer 2

Fever + new murmur

Question 3

What types of IE are there?

Answer 3

Native = affects natural valves

Prosthetic = prosthetic valves

Device related: pacemakers, defibrillators etc.

Question 4

Is it more common to get prosthetic IE in your left or right valves?

Answer 4

Left, since its rare to have your right valves replaced

Question 5

Which valves are found on the right side of the heart?

Answer 5

Tricuspid valves

Pulmonary valves

Question 6

Which valves are found on the left side of the heart?

Answer 6

Bicuspid (mitral) valves

Aortic valves

Question 7

What is the difference between early and late prosthetic IE?

Answer 7

Early occurs within a year of operation and the infection is likely to have been introduced during the operation

Late occurs at least a year after the operation. Unlikely to have been introduced during operation

Question 8

What % of cases of IE occur on normal valves?

Answer 8

50%

Question 9

What are the risk factors for IE?

Answer 9

Valve disease
Congenital cardiac disease
IVDU
Invasive IV procedures
Dental procedures
Elderly
Very young

Question 10

Which bug is usually the culprit of IE?

Answer 10

Staph aureus

Strep viridans
Strep A, B, C, D
Staph epidermidis
Pseudomonas
Enterococci

Kingella kingae
Cardiobacterium

Question 11

How do the heart valves end up getting infected?

Answer 11

A damaged valve forms a blood clot

Platelets and fibrin accumulate

Bacteria adhere to the platelet + fibrin site on the heart valve

More and more bacteria accumulate forming lumps of infected fibrin/clot on the valves called vegetation

Question 12

What is vegetation?

Answer 12

A lump of infected fibrin and blood clot hanging off the heart valve

Question 13

What causes heart valve damage?

Answer 13

Altered/turbulent blood flow leading to fibrosis and clot formation

Catheters, electrodes, prostheses etc. that might be inserted into the heart

Solid particles from repeated IV injections

Chronic inflammation: auto-immune conditions

Question 14

How do IE patients present?

Answer 14

Fever

A new heart murmur

Embolic events of unknown origin:

Sepsis of unknown origin

Peripheral stigmata

Question 15

What complications can happen to the vegetation on heart valves?

How might this present?

Answer 15

The vegetation can break off and become an embolus
Causing blockages of other vessels and introducing infection to other parts of the body

Stroke
PE
Bone infections
Kidney dysfunction
MI
Abscesses in any part of the body

Question 16

What are the peripheral stigmata of IE?

Answer 16

Petechiae: small red/purple spot caused by bleeding into the skin

Janeway lesions: non-tender, small red lesions on the palms

Splinter haemorrhages: tiny haemorrhages under fingernail

Osler’s nodes: small, painful, red subcutaneous nodules on the pulp of the digits

Question 17

Investigations for IE?

Answer 17

Bloods: FBC, UE, CRP
Blood cultures (during fever)

Echo: transthoracic or trans-oesoph, look for
vegetation on heart valve, abscess, new valvular regurgitation

CXR: cardiomegaly
ECG

Question 18

What blood tests need to be done? And what results might you see?

Answer 18

-FBC:
May see normo-chromic + cytic anaemia
White count is not useful
IgG presence

-U+E

-ESR/CRP
Raised usually

-Microbiology:
Don't always see anything!
3 sets at
3 different times from
3 different sites at peak of fever

Question 19

Why might you not see anything on blood microbiology tests?

Answer 19

Often, the patient presented to their GP with a non-specific infection

The doctor, unsure what the infection was, simply prescribed antibiotics which might have started to kill of bacteria

Question 20

Management of IE?

Answer 20

Anti-microbials: long course via Hickman line
Before cultures: amoxicillin or if severe vancomycin
If prosthetic: vanc + gent + rifamp

Then, depends on bug:

• Staph: fluclox, vanc, rifamp
• Strep: Ben-Pen

Treat complications: heart failure, arrhythmia, heart block

Surgery: only if really serious

Question 21

Which fungi are often the culprits of IE?

Answer 21

Candida

Aspergillus

Question 22

In what situations should you operate in IE?

Answer 22

The infection can’t be cured with antibiotics

Complications: severe valve damage, aortic root abscess

To remove infected prostheses

To remove large vegetations before they embolise

Question 23

Diagnostic criteria of IE?

Answer 23

Duke’s

Major:
\+ve blood cultures on two occasions
\+ve findings of IE on ECHO
- mass on valves
- abscess
- new valvular regurgitation

Minor:

• temp over 38
• IVDU or heart structural disease
• Vascular phenomenon: Janeway, splinter + conjunctival haemorrhages
• Immuno phenomenon: Osler’s, glomerulonephritis

Question 24

List vascular and immunological phenomena of IE?

Answer 24

Vascular: Janeway lesions, splinter and conjunctival haemorrhages

Immunological: Osler’s nodes, glomerulonephritis, rheumatoid factor