CVS -Part 2

Question 1

What is infective endocarditis

Answer 1

An infection of the endocardium or vascular endothelium of the heart.
Known as subacute bacterial endocarditis.

Question 2

Where can infective endocarditis infections occur?

Answer 2

• Valves with congenital or acquired defects (usually on the left side of the heart). Right sided endocarditis is more common in IV drug addicts
• Normal valves with virulent organisms such as Streptococcus pneumoniae or Staphylococcus aureus
• Prosthetic valves and pacemakers

Question 3

Infective Endocarditis: more common in men or women

Answer 3

Men

Question 4

Infective Endocarditis: in what countries is it more common?

Answer 4

Developing countries

Question 5

Infective Endocarditis: In what people is it more common

Answer 5

• men
• the elderly or those with prosthetic valves
• the young IV drug user
• the young with congenital heart disease

Question 6

Aetiology of infective endocarditis?

Answer 6

Staphylococcus aureus (IVDU, diabetes and surgery) - most common cause
Pseudomonas aeruginosa
Streptococcus viridans (dental problems) - GRAM POSITIVE, alpha haemolytic and optochin resistant (Strep. mutans, strep, sanguis, strep. milleri & strep. oralis)

Question 7

Risk factors of infective endocarditis

Answer 7

• IV drug use
• Poor dental hygiene
• Skin and soft tissue infection
• Dental treatment
• IV cannula
• Cardiac surgery
• Pacemaker

Question 8

Pathophysiology of infective endocarditis

Answer 8

Usually results from one of:

• presence of organisms in the bloodstream
• abnormal cardiac endothelium that facilitates their adherence and growth

Bacteraemia may arise for patient-specific reasons e.g. poor dental hygiene, IV drug use, soft tissue infections

Can be associated with diagnostic or therapeutic procedures such as dental treatment, intravascular cannula, cardiac surgery, permanent pacemakers

Damaged endocardium promotes platelet and fibrin deposition, which allows organisms to adhere and grow, leading to an infected vegetation

Virulent organisms destroy the valve they are on resulting in regurgitation and worsening heart failure

Question 9

Why can poor dental hygiene lead to bacteraemia?

Answer 9

bacteria in tooth plaque can cause gum disease which results in bleeding and inflammation of gums meaning when brushing/in dental procedure this bacteria can enter the bloodstream and reach the heart

Question 10

Clinical manifestations of infective endocarditis

Answer 10

Splinter haemorrhages on nail beds of fingers
Embolic skin lesions - black spots on skin (infarcts causes by bits of
infective vegetation blocking small capillaries)
Osler nodes - tender nodules in the digits
Janeway lesions - haemorrhages and nodules in the fingers
Roth spots - retinal haemorrhages with white or clear centres seen on fundoscopy
Petechiae - small red/purple spots caused by bleeds in the skin

Question 11

High suspicion clinical presentation of infective endocarditis

Answer 11

• New valve lesion/regurgitant murmur
• Embolic events of unknown origin
• Sepsis of unknown origin
• Haematuria, glomerulonephritis and suspected renal infarction
• Fever plus:
- Prosthetic material inside the heart
- Risk factor for infective endocarditis e.g. IV drug user
- Newly developed ventricular arrhythmias or conduction disturbances

Question 12

General clinical presentation of IEndocarditis

Answer 12

Headache, fever, malaise, confusion, and night sweats - quite unspecific so often misdiagnosed and missed
Also finger clubbing
If Staphylococcus aureus then will develop very quickly - high fever and feel
ill rapidly, with the other virulent ones you don’t feel as ill Embolisation of vegetations e.g. stroke, pulmonary embolus, bone
infections, kidney dysfunction and myocardial infarction Valve dysfunction result in in arrhythmia and heart failure
Endocarditis should be excluded in ANY patient with a heart murmur and fever

Question 13

Diagnosis of Infective Endocarditis

Answer 13

DUKES Criteria
Urinalysis - look for haematuria
CXR - cardiomegaly
ECG - long PR interval at regular intervals
Echocardiogram

Blood cultures (3 sets from different sites over 24 hours, take BEFORE antibiotics started, identifies 75% of cases)

Blood test (CRP and ESR raised; neutrophilia; normochromic (normal conc of Hb), normocyctic (Norm size of RBCs) anaemia)

Question 14

What are 2 options of echocardiogram for diagnosis of Infective Endocarditis

Answer 14

• Transthoracic echo (TTE) - safe, non invasive, no discomfort BUT often poor images so low sensitivity but can identify vegetations (if greater than 2mm) - however a negative TTE DOES NOT exclude the diagnosis of infective endocarditis
• Transoesophageal echo (TOE) - much more sensitive but very uncomfortable, is useful for visualising mitral lesions and possible development of aortic root abscess

Question 15

Is Transthoracic echocardiogram (TTE) or Transoesophageal echocardiogram (TOE) better at diagnosing (Infective Endocarditis)?

Answer 15

TOE - Transoesophageal echo

Question 16

Treatment of Infective Endocarditis

Answer 16

Antibiotics for 4-6 wks
Treat complications e.g. arrhythmia, heart failure, heart block, embolisation, stroke rehab and abscess drainage
Surgery - removing valve and replacing with prosthetic one:
• Operate if the infection cannot be cured with antibiotics i.e. returns after treatment
• Operate to remove infected devices
• Operate to remove large vegetations before they embolise
In term of prevention recommend GOOD ORAL HEALTH and inform patients
of symptoms that may indicate infective endocarditis

Question 17

Treatment of Infective Endocarditis: If NOT staphylococcus, what drug would you give?

Answer 17

Penicillin

ideally Benzylpenicillin & Gentamycin (doesn’t work on own since cannot get through bacterial cell wall)

Question 18

Treatment of Infective Endocarditis: if staphylococcus, what drug would you give?

Answer 18

Vancomycin

Rifampicin (if MRSA)