W4 20 endocarditis and septicaemia

Question 1

How does blood move through the heart?

Answer 1

Arterial blood from the lungs to the left atrium to the left ventricle, out to the aorta to the rest of the body. From the body blood enters the heart via the superior and inferior vena cavas.

Question 2

What valves are in the left side circulation? (Img pg223)

Answer 2

Left atrium and left ventricle are separated by the mitral (bicuspid) valve
Left ventricle and aorta separated by the aortic valve

Question 3

What happens if a lump of bacteria sits on the aortic valve?

Answer 3

It’ll continue to get bigger, break off and spread to the rest of the body, eg brain causing stroke, kidneys causing renal ischaemic, coronary arteries causing heart attack

Question 4

What valves are in the right side circulation?

Answer 4

Right atrium and right ventricle separated by tricuspid valve
Right ventricle and pulmonary artery to lungs are separated by pulmonary valve

Question 5

Where do IV drug users inject and what will this cause (and by what bacteria)?

Answer 5

They inject into the femoral vein, inoculating bacteria, flowing to the right atrium into right ventricle. This will affect the tricuspid valve. Commonly Staph aureus infection for IV drug users.

Question 6

What are the layers of the cardiac wall? (Pg224)

Answer 6

Pericardium - outermost layer consisting of parietal pericardium, pericardial cavity and visceral pericardium
Myocardium - cardiac muscle layer (forming bulk - middle)
Endocardium - endothelial layer of inner myocardial surface (innermost layer)

Question 7

What is pericarditis and myocarditis?

Answer 7

Pericarditis - condition caused by inflammation of the pericardium
Myocarditis - inflammation of myocardium
Infective causes for both - usually viral (rarely bacterial)

Question 8

What is endocarditis?

Answer 8

Infection of the hearts endocardial surface.

Question 9

What are some risk factors for endocarditis?

Answer 9

Cardiac conditions
Lifestyle - IV drug use
Procedure related - intravascular devices, bacteraemia

Question 10

What sort of cardiac conditions are risk factors for endocarditis?

Answer 10

Congenital heart disease (bicuspid valve, ventricular septal defect)
Valvular heart disease (aortic stenosis/regurgitation/prolapse)
Prosthetic heart valve (sometimes after previous endocarditis)
Previous infective endocarditis (vegetation of valve affects structure of valve etc) - age related; high cholesterol causing ischaemia; complications of myocardial infarction

Question 11

Endocarditis can be classified by acute and subacute. Describe the features of acute endocarditis.

Answer 11

Healthy, normal valves
Sudden
Rapidly progressive
Patient suddenly very unwell
Mortality high
Usually staph aureus

Question 12

Endocarditis can be classified by acute and subacute. Describe the features of subacute endocarditis.

Answer 12

Pre-existing valve disease
Indolent (causing little or no pain)
Slowly progressive
Patient unwell for few weeks
Mortality also high
Usually streptococci/coagulase negative staph (eg staph epidermidis)

Question 13

Other classifications of endocarditis involve native valve endocarditis, prosthetic valve endocarditis, IV drug use (IVDU). What causes native valve endocarditis?

Answer 13

Commonly Staph aureus, streptococci, HÁČEK group (uncommon)

Question 14

What is the commonest isolate in IVDUs (exam favourite!)?

Answer 14

Staph aureus

Question 15

Describe IE associated with colon malignancy (exam favourite!)

Answer 15

Caused by Streptococcus bovis
Immediately screen for bowel cancer
Likes to live in gut and if spilled out onto gut, might be a defect in the gut wall leading to a bacteraemia and seeding onto the heart valves.

Question 16

What is IE with emboli to multiple organs likely affecting? (Exam favourite!)

Answer 16

Likely the left-heart valve - aortic valve

Question 17

What is IE with emboli to lungs likely affecting? (Exam favourite!)

Answer 17

Likely right-heart valve - tricuspid valve

Question 18

What may culture negative endocarditis be caused by? (exam favourite!)

Answer 18

Coxiella

Question 19

What is the pathogenesis of endocarditis?

Answer 19

1. Alteration of valvular endothelium leading to deposition of platelets and fibrin
2. Bacteraemia with seeing of thrombotic vegetation
   3l adherence and growth, further platelet and fibrin deposition
3. Extension to adjacent structures, eg papillary muscle, valvular ring abscess, cardiac conduction tissue (can cause arrhythmia)

Question 20

What are the complications of endocarditis from the local spread of infection?

Answer 20

Heart failure - extensive valve damage
Valvular abscess - most common in IVDU, can cause arrhythmias
Pericarditis
Fistulous intracardiac connections

Question 21

What are the complications of endocarditis from embolism phenomena?

Answer 21

Myocardial infarction
Stroke
Pulmonary emboli (dyspnea, pleuritic chest pain)
Splenic and renal infarcts
Discitis, septic arthritis
Mycotic aneurysm - large aorta gets a bacterial mass and can rupture

Question 22

What are the non-specific symptoms of acute and subacute endocarditis and when do they start?

Answer 22

Usually start 2 weeks after initial bacteraemia. Diagnosis usually after 5.
Acute endocarditis - patient has very high fever (40°) and looks acutely ill
Subacute - low grade fever, night sweats, fatigue, malaise, anorexia, weight loss
Some pt report symptoms related to embolic phenomena eg dyspnea with PE, back pain with discitis, facial droop with stroke

Question 23

Some signs of endocarditis (img pg226)

Answer 23

Fever and new murmur = endocarditis until proven otherwise
Roth spots
Jane way lesions
Osler’s nodes
Haematuria
Splenomegaly
Conjunctival petechiae

Question 24

What investigations can be taken for endocarditis?

Answer 24

ECG - as maybe conduction abnormalities
Urine dip - for haematuria
Bloods - FBC, U&E, CRP
Blood cultures
Chest x-ray - to check for other chest pain reasons
Echocardiography - for visible mass on valve

Question 25

When and why do you take blood cultures in endocarditis, and why is it different to fever?

Answer 25

If subacute take 3 at least 6 hours apart. Don’t jump to antibiotics without know the bug. Unrelated to fevers - in endocarditis the level of bacteraemia is constant. The blood sitting on the heart valve flows through the heart so bacteraemia flows around the body. In usual practice for a fever, take a blood culture while feverish because in other scenarios like an abscess, when they have a fever is the highest level of bacteria in the blood.

Question 26

Why might endocarditis cause haematuria?

Answer 26

In the event of emboli, there is renal ischaemia, the glomeruli are disrupted so the blood tends to escape into the urinary tract.

Question 27

What are the different echocardiograms done?

Answer 27

Transthoracic - TEE - ultrasound onto chest wall Transoesophageal - TOE, done if TEE is negative. Light sedation, probe through oesophagus and looking at valves from back of heart. Useful in obesity since no chest wall tissue obstructing view.

Question 28

What are the 2 major criteria for the diagnosis of endocarditis?

Answer 28

Blood cultures for infective endocarditis Evidence of endocardial involvement

Question 29

What are the 7 minor criteria for endocarditis diagnosis?

Answer 29

Predisposing factor Temperature >38°C Vascular phenomena Immunological phenomena Microbiological evidence PCR Echo not meeting major criteria

Question 30

How many major/minor criteria are needed for the diagnosis of endocarditis?

Answer 30

Definitive diagnosis: 2 major criteria, 1 major and 3 minor, 5 minor Possible diagnosis: 1 major 1 minor, 3 minor

Question 31

PG228 - what is the modified duke criteria explanations

Answer 31

Please just read pg228 images I cba cos it doesn’t go through it in the lecture but think it would be useful to read over.

Question 32

How do you manage patients with suspected endocarditis?

Answer 32

If come in and are stable, take 3 blood cultures 6 hours apart, get the echo, grow something and start tailored antibiotics Fever may persist for several days after starting treatment and can be relieved with paracetamol Intravenous antibiotics, talk to an infection specialist, probs 4-6 weeks +- surgery Surgery if: uncontrolled infection; extremely larger vegetations >1cm Always refer to hospital prior to starting antibiotics?

Question 33

You should always test before giving antibiotics, but what are the most likely ones if endocarditis is following a dental procedure or they are an IV user?

Answer 33

Recent dental procedures - amoxicillin - usually virudent streptococci and bugs living in the mouth IVDU - broad cover antibiotic

Question 34

What are the different guidelines for antibiotic prophylaxis?

Answer 34

NICE (UK) - says no prophylaxis to anyone. But warn patients of signs and symptoms of endocarditis, advise good oral health, warn of risks of other invasive procedures, explain why antibiotic prophylaxis might not be the best ESC (Europe) and USA say yes for high risk groups only - 1 dose amoxicillin 2g for high risk patients undergoing high risk dental procedures. Controversial.

Question 35

What procedures are invasive to be causing bacteraemia?

Answer 35

Dental, neurological, gastric procedures etc Non medical - eg tattooing or piercing

Question 36

Should chlorhexidine mouthwash be offered as prophylaxis against infective endocarditis to people undergoing dental procedures?

Answer 36

No, due to chlorhexidine resistance and not enough days to back up it being beneficial

Question 37

What is the risk of antibiotic prophylaxis?

Answer 37

Increases risk of AMR Adverse drug reaction Cost (due to high frequency of dental procedures)

Question 38

What are some high risk of IE groups according to NICE?

Answer 38

Acquired valvular heart disease with stenosis or regurgitation Hypertrophic cardiomyopathy Previous IE Structural congenital heart disease eg septal defects Valve replacements Europeans give to people with heart transplant after first 6 months

Question 39

What are the European guidelines for high risk procedures?

Answer 39

Tooth extraction Periodontal surgery, subgingival scaling and root planing Replanting of avulsed teeth Other surgical procedures eg implant placement of apicoectomy

Question 40

Case studies/quiz in this lec

Answer 40

Pg 231/ min48-58 of lec