Endocarditis

Question 1

Usually the endocardium is

Answer 1

non-sticky and resistant to bacterial seeding

Question 2

most cases of endocarditis are associated with

Answer 2

structural defect of the bicuspid aortic valve

Question 3

when does endocarditis generally occur

Answer 3

Endocarditis generally occurs when bacteria or fungi another part of your body, such as your mouth, spread through your bloodstream and attach to damaged areas in your heart. If it’s not treated quickly, endocarditis can damage or destroy your heart valves and can lead to life-threatening complications.

Question 4

patient risk factors

Answer 4

• Everyday oral activities- such as brushing teeth (activities which may cause gums to bleed), allow bacteria to enter bloodstream
• Catheters
• Needles for tattoos and body piercing
• IV drug use
• Certain dental procedures

Question 5

activities which put you at risk of endocarditis

Answer 5

Bicuspid aortic valve is the most common congenital cardiac defect

Question 6

bicuspid aortic valve

Answer 6

• Result of abnormal aortic cusp formation during valvulogenesis.
• Adjacent cusps fuse to form a single aberrant cusp, larger than its counterpart yet smaller than 2 normal cusps combined
• Range of tissue, molecular and genetic abnormalities

Question 7

why does it increase risk of endocarditis

Answer 7

• Abnormal flow of blood over the valve and associated abnormal valve tissue
• Greater risk of microbes in the blood sticking to the valve cusp and setting up a local infection (with a biofilm)

Question 8

other causes of endocarditis

Answer 8

• Artificial heart valve – more likely to attach to artificial heart valve
• History of endocarditis
• Damaged heart valve

Question 10

bacterial pathogens

Answer 10

Staphylococcus aureus

Viridans Streptococcus

Coagulase negative staphylococci

Enterococci

Question 11

fungal pathogens

Answer 11

Candida albicans

Aspergillus

Question 12

Patient symptoms

Answer 12

• Fever
• Heart murmur
• Other cardiac complications
• Embolic features- small bits of vegetation (or biofilm) that become loose and travel to small capillaries where they can block the capillary or cause local infection

Question 13

Embolic features

Answer 13

• janeway lesions
• splinter haemorrhages
• roth spots in the eye
• oslers nodes

Question 14

Janeway lesions

Answer 14

• haemorrhagic nodular lesion with irregular border present on palms and soles. Micro-abscess formation and localised necrosis

Question 15

Splinter haemorrhages

Answer 15

• These are linear minute capillary engorgements usually in distal third of the nail bed.

Question 16

Roth spots in the eye

Answer 16

• These are described as linear haemorrhagic spots seen in the retina of the eye

Question 17

Oslers nodes

Answer 17

• These are painful, erythematous nodules on pads of fingers and toes. They may have a dual aetiology as they are related to both: septic micro-emboli and immune complex related vasculitis

Question 18

Hallmark of endocarditis is the formation of

Answer 18

vegetation (biofilm) that binds to valves or mural endocardium

Question 19

Three hallmarks of endocarditis:

Answer 19

1. Constitutional symptoms which are cytokine mediated
2. Local spread of infection causing myocardium destruction
3. Distal blood borne septic embolization
   4.

Question 21

mechanism of action

Answer 21

1. Aberrant flow predisposes to a collection of fibrin, platelets and scant inflammatory cells –> formation of vegetation
2. Microorganisms that enter blood stream from:
   
   • Skin
   • Mucosa etc
3. These bind to vegetation and cause local infection leading to a pro-coagulant state
4. Further fibrin deposition, platelet aggregation and bacterial invasion lead to an infection cascade causing infective carditis
5. Bacterial colonies deep within vegetation are dormant and hard to eradicate using antibiotics
6. Superficial colonies tend to embolise (lodge and obstruct) distally causing septic phenomenon as well as reinfection of vegetation
7. Vegetation is a BIOFILM

Question 22

virulence factor of s.aureus

Answer 22

S.aureus has fibronectin binding proteins and is capable of binding to intact endothelium and therefore can infect previously uninfected endocardium

Question 23

Diagnosis

Answer 23

Follow: Duke Criteria for diagnosing endocarditis.

This includes:

• Standard features of infection such as fever
• Cardiac features such as a murmur
• Microbiological features- such as a positive blood culture
• Embolic features relating to the vegetation/ biofilm and release of bit vegetation (biofilm) into the blood stream

Question 24

For the purpose of determining the duration of therapy

Answer 24

the first day in which negative blood cultures are obtained is considered the first day of therapy

Question 25

succesfful treatment requires

Answer 25

appropriate antibiotic therapy (emperic therapy- educated gueess)

Question 26

types of antibiotics given

Answer 26

* Vancomycin or ampicillin plus aminoglycoside * Septic antibiotics will depend on the given organism

Question 27

surgery

Answer 27

(only needed in some patients) Structural and functional integrity of cardiac valves may be damaged by infection--\> valvular regurgitation or flow obstruction in valves with large vegetations

Question 28

preventative antibiotics

Answer 28

Certain dental and medical procedures may allow bacteria to enter your bloodstream. For some people with heart disease or damaged or diseased heart valves, taking antibiotics before these procedures can help destroy or control the harmful bacteria that may lead to endocarditis. This is because these people are more at risk of developing endocarditis after having these procedures.

Question 29

outcome of infections: complications

Answer 29

* Heart problems e.g. murmur, valve damage, heart failure * Stroke * Seizure * Paralysis * Pulmonary embolism if infected vegetation travels to the lungs and blocks a lung artery * Kidney damaged * Enlarged spleen