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Cardiovascular > Infective endocarditis > Flashcards

Infective endocarditis Flashcards

1
Q

What is infective endocarditis?

A

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

Plus showers of infectious material around your bloodstream, and/or damaging the heart valves to cause heart failure.

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2
Q

Epidemiology of IE

A
  • IE is a rare disease. Between 2009-2010, there were 3,969 episodes of acute and subacute endocarditis in the UK
  • M>F
  • More common in developing countries
  • The mitral valve is most commonly affected overall
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3
Q

What is the treatment for IE?

A
  • Main is antibiotics/antimicrobials: intravenous for around 6weeks; choice of agent/s based on culture sensitivities
  • May require cardiac surgery to remove the infectious material and/or repair the damage
  • Treatment of other complications- emboli, arrythmia, heart failure, heart block, stroke rehab, access drainage etc)
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4
Q

Endocarditis categories

A

Non-bacterial thrombotic ‘marantic’:

  • Anon-infectivecause of endocarditis secondary to thrombus formation on the valvular surface
  • Associated withmalignancyor SLE (Libman-Sacks endocarditis: antigen-antibody complexes attack the endocardium)

Acute:

  • Develops over days to weeks
  • Most commonly associated withS. aureus
  • Rapid valvular destruction

Subacute:

  • Develops over weeks to months
  • Most commonly associated withS. viridans
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5
Q

Types of IE

A

Left sided native IE (mitral or aortic)

Left sided prosthetic IE

Right sided IE (rarely prosthetic as rare to have PV or TV replaced)

Device related IE (pacemakers, defibrillators, with or without valve IE

Prosthetic; can be Early (within year) or Late (after a year) post op

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6
Q

How does someone get IE?

A
  • Have an abnormal valve; regurgitant or prosthetic valves are most likely to get infected.
  • Introduce infectious material into the blood stream or directly onto the heart during surgery
  • Have had IE previously
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7
Q

Who does IE mostly affect? RFs

A

the elderly (in an ageing population)
the young i.v. drug abusers
the young with congenital heart disease.
Anyone with prosthetic heart valves
Males
Poor dental hygiene
Immunosuppressed

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8
Q

Pathophysiology

A

Abnornal endocardium causes turbulent blood flow - damaged endothelium exposed underlying collagen and TF > platelets and fibrin adhere forming a thrombus - if bacteria added to this get IE

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9
Q

How do microbes attach to thrombus on endocardium

A
  • Use adhesins to adhere to one another creating a biofilm allowing them to aggregate
  • Happen normally in lower pressure
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10
Q

How does endocarditis present clinically?

A
  • Depends on site, organism, etc
  • Signs of systemic infection (fever, sweats, etc)
  • Embolisation; stroke, pulmonary embolus, bone infections, kidney dysfunction, myocardial infarction
  • Valve dysfunction; heart failure, arrythmia
  • Lots of different presentations
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11
Q

What is the Modified Dukes criteria?

A

Used to diagnose IE

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12
Q

What are the major criteria for MDC?

A
  • Pathogen grown from blood cultures
  • evidence of endocarditis on echo
  • new valve leak
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13
Q

What are the minor criteria for MDC?

A
  • Predisposing factors
  • Fever
  • Vascular phenomena
  • Immune phenomena
  • Equivocal blood cultures
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14
Q

What symptoms of MDC show definite IE?

A

2 major, 1 major+3 minor, 5 minor

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15
Q

What symptoms of MDC show possible IE?

A

1 major, 1 major+3 minor, 5 minor

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16
Q

What are the typical microorganisms consistent with IE?

A

Viridians streptococci
Streptococcus bovis
HACEK group
SA
Community acquired enterococci

17
Q

Primary investigations of IE

A
  • Inflammatory markers:raised WCC often with neutrophilia, as well as raised CRP and ESR
  • Blood cultures
  • CXR
  • 12 lead ECG
18
Q

What is technique is primarily used to find IE?

A

Echocardiography
Echocardiogram

19
Q

Transthoracic echo (TTE)

A

Safe, non-invasive, no discomfort, often poor images so lower sensitivity

20
Q

Transoesophageal (TOE/TEE). (Echocardiogram)

A

Excellent pictures but more invasive. Patients rarely want to have a second TOE. Generally safe but risk of perforation or aspiration.

21
Q

What are the symptoms of IE called? (Also called this for other diseases)

A

Peripheral stigmata

22
Q

Examples of peripheral stigmata?

A

Petechiae 10 to 15%, - bruising
Splinter hemorrhages
Osler’s nodes (small, tender, purple, erythematous subcutaneous nodules are usually found on the pulp of the digits- embolization)
Janeway lesions are erythematous, macular, nontender lesions on the fingers, palm, or sole
Roth spots on fundoscopy.
Heart murmur

23
Q

Where are Macular petechial and embolic skin lesions found?

A

Tips of fingers and around nails

24
Q

Where are splinter haemorrhages found?

A

Tiny little red lines at end of finger nails

25
Q

What are osler’s nodes?

A

Tender nodules in the fingers of a patient with infective endocarditis.

26
Q

Symptoms of IE

A
  • Fever or chills
  • Headache
  • Shortness of breath
  • Night sweats, malaise, fatigue, weight loss
  • Joint pain
27
Q

For the diagnosis of IE:

A
  • Cultures may remain negative in 2% to 5% of patients with IE.
  • Certain organisms: cell media; special media or microbiological methods, or may require long incubtion 7-21/7.
  • The most common cause for negative blood cultures in patients with IE is prior antimicrobial therapy.
  • WBC is rarely helpful.
  • Raised CRP is almost always present.
28
Q

How can we use ECG for IE diagnoses?

A

ECG (ischemia or infarction, new appearance of heart block)

29
Q

Whats important in detecting a vegetation?

A

TTE

30
Q

Why can we not just use transthoracic 2D echocardiography?

A

sensitivity of transthoracic 2-D echocardiography is still only about 60%; may need transoesophageal echo either for diagnosis or to assess complications such as:

severity of valve damage
aortic abscess formation
function of prosthesis

31
Q

Whats the best echo to use?

A

Transoesophageal echo (TOE) has improved the rate of detection of vegetations on native valves to 90–95%
TOE improves the sensitivity of detecting vegetations on prosthetic valves to up to 96%
A negative TTE/TOE does not eliminate the possibility that IE is present.

32
Q

When do we operate for IE?

A
  • the infection cannot be cured with antibiotics (ie recurs after treatment, or CRP doesn’t fall)
  • complications (aortic root abscess, severe valve damage)
  • to remove infected devices (always needed)
  • to replace valve after infection cured (may be weeks/months/years later
  • To remove large vegetations before they embolise
33
Q

Management of IE

A

1st line - IV antibiotics for 4-6 weeks
2nd line surgery

34
Q

IE complications

A
  • Regurgitation
  • Congestive HF
  • Septic embolism

Cardiovascular (14 decks)

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