Infective Endocarditis Flashcards
What is infective endocarditis?
Inflammation of the inner tissues of the heart, especially the heart valves
Caused by infectious agents
What two symptoms are said to indicate endocarditis until proven otherwise?
Fever + new murmur
What types of IE are there?
Native = affects natural valves
Prosthetic = prosthetic valves
Device related: pacemakers, defibrillators etc.
Is it more common to get prosthetic IE in your left or right valves?
Left, since its rare to have your right valves replaced
Which valves are found on the right side of the heart?
Tricuspid valves
Pulmonary valves
Which valves are found on the left side of the heart?
Bicuspid (mitral) valves
Aortic valves
What is the difference between early and late prosthetic IE?
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
What % of cases of IE occur on normal valves?
50%
What are the risk factors for IE?
Valve disease Congenital cardiac disease IVDU Invasive IV procedures Dental procedures Elderly Very young
Which bug is usually the culprit of IE?
Staph aureus
Strep viridans Strep A, B, C, D Staph epidermidis Pseudomonas Enterococci
Kingella kingae
Cardiobacterium
How do the heart valves end up getting infected?
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
What is vegetation?
A lump of infected fibrin and blood clot hanging off the heart valve
What causes heart valve damage?
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
How do IE patients present?
Fever
A new heart murmur
Embolic events of unknown origin:
Sepsis of unknown origin
Peripheral stigmata
What complications can happen to the vegetation on heart valves?
How might this present?
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
What are the peripheral stigmata of IE?
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
Investigations for IE?
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
What blood tests need to be done? And what results might you see?
-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
Why might you not see anything on blood microbiology tests?
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
Management of IE?
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
Which fungi are often the culprits of IE?
Candida
Aspergillus
In what situations should you operate in IE?
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
Diagnostic criteria of IE?
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
List vascular and immunological phenomena of IE?
Vascular: Janeway lesions, splinter and conjunctival haemorrhages
Immunological: Osler’s nodes, glomerulonephritis, rheumatoid factor
