Infective Endocarditis

Question 1

Risk factors for IE

Answer 1

Prosthetic heart valve/prosthetic material in-situ following a cardiac value repair
History of previous IE
IV drug use
Heart surgery
Untreated cyanotic congenital heart disease

Question 2

Symptoms and signs of IE?

Answer 2

Persistent fever (less common if elderly or immunosuppressed), sweats, malaise, SOB, poor appetite, weight loss.

A new (or changing) heart murmur (85% patients)
Harsh systolic murmur and palpable thrill

Embolic phenomenon (25% patients)

Question 3

What progression (timing) of the disease can be seen?

Answer 3

Acute, sub-acute, chronic

Question 4

What peripheral stigmata of IE may be seen?

Are these commonly seen?

Answer 4

Janeway lesions (palms)
Osler nodes (finger pads)
Roth spots (fundoscopy)
Splinter haemorrhages (nails)

Late clinical manifestations and increasingly uncommon in the developed world.

Question 5

What are some less common signs of IE?

Answer 5

Splenomegaly, anaemia, arthritis, congestive cardiac failure, renal involvement.

Question 6

What investigations should be performed?

Answer 6

Full blood count: Renal function, CRP, ESR
Blood cultures: 3 at 30 minute intervals
Urine dipstick: proteinuria and microscopic haematuria
Transthoracic echo (TTE)
(If TTE -ve but high suspision, a transoesophangel echo (TOE) may be performed)

Question 7

What criteria can be used to support the diagnosis?

Answer 7

The modified Duke’s critieria

Question 8

What organism is likely causative organism?

Answer 8

Staphylococcus aureus (30%)
Enterococcus (if urinary source ie. catheter which is traumatic and introduces bacteria to bloodstream - for this reason a prophylactic abx may be used)
Strep. viridans

Question 9

How might the disease be prevented?

Answer 9

Antibiotic prophylaxis for high risk patients:
Traumatic catheterisation or suprapubic catheterisation
Strict dental and cutaneous hygiene
Curative antibiotics
Infection protocols
Avoidance or piercings/tattoos
Peripheral over central canulas

Question 10

What infective organism is the most common cause of IE in intravenous drug users?

Answer 10

Staphylococcus aureus

Most commoly affects the right side of the hear and can cause septic emboli which can travel to the lungs.

Question 11

What is the treatment of acute IE?

Answer 11

Enterococcus IE is treated with
4-6 weeks of Amoxicillin and Gentamycin
(Difficult to reach the infection)

Question 12

Complications of IE?

Answer 12

Systemic embolisation
Heart failure (from destruction of tissues)
Uncontrolled infection
Neurological Complications
Splenic aneurysms
Myocarditis/pericarditis
Arrythmias and conduction disturbances
Renal failure

Question 13

What management may be required if antibiotic treatment is ineffective?

Answer 13

Surgery
Absolute indications include:
Abscess formation
Acute valvular regurgitation with pulmonary oedema
Dehiscence of a prosthetic valve

Question 14

What is infective endocarditis?

Answer 14

Infection of the heart valve/s or other endocardial lined structures within the heart (such as septal defects, packmaker leads, surgical patches, etc)

Question 15

What are the most common types of IE?

Answer 15

Left sided native IE (mitral or aortic)
Left sided prosthetic IE
Right sided IE (rarely prosthetic as rare to have replaced)
Device related IE (pacemakes etc.)

Question 16

What is the epidemiology of IE?

Answer 16

Previously: Young with rheumatic heart disease
Now:
Elderly, young IV drug users, young with congenital defects, prosthetic heart valves.