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Cardiology > Infective endocarditis > Flashcards

Infective endocarditis Flashcards

1
Q

What is infective endocarditis?

A

-infection of the endothelium of the heart

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2
Q

What are four predisposing factors for infective endocarditis?

A

Heart valve abnormality:

  • calcification/sclerosis in elderly
  • congenital heart disease
  • post rheumatic fever

Prosthetic heart valve

Intravenous drug users

Intravascular lines

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3
Q

What is the pathogenesis of infective endocarditis?

A

Heart valve damaged

Turbulent blood flow over roughened endothelium

Platelets / fibrin deposited

Bacteraemia (may be very transient) e.g. from dental treatment

organisms settle in fibrin/platelet thrombi becoming a microbial vegetation

Infected vegetations are friable and break off, becoming lodged in the next capillary bed they encounter causing abscesses or haemorrhage - may be fatal

Usually left side of heart affected (mitral and aortic valves) unless IDU and then it’s right sided

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4
Q

What organisms cause endocarditis in a native heart valve? (4)

A 
Staphylococcus aureus	(38%) - IVDU
Viridans streptococci	(31%) - mouth/dentist
Enterococcus sp 	(8%) 
Staph epidermidis 	(6%) - indwelling lines/surgery
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5
Q

What are the unusual organisms that cause endocarditis?

A

Atypical organisms:
Bartonella, Coxiella burnetii (Q-fever), Chlamydia, Legionella, Mycoplasma, Brucella

Gram-negatives:
-HACEK organisms:
Haemophilus spp. , Aggregatibacter spp, ( was Actinobacillus) , Cardiobacterium, Eikenella sp., Kingella sp.
-Non HACEK gram negatives

Fungi - in immunocompromised individuals/IVDU/IV lines

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6
Q

What two signs = endocarditis until proven otherwise?

A

New murmur + fever

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7
Q

describe the clinical features of an acute endocarditis? 10

A
  • fever
  • new heart murmur
  • haematuria (secondary to renal failure)
  • rigors
  • night sweats
  • splinter haemorrhages
  • nail fold infarcts
  • roth spots
  • embolic incidents (TIA/Stroke 15%)
  • malaise

Overwhelming sepsis and cardiac failure usually due to staph aureus

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8
Q

In subacute endocarditis what are the clinical features? 8

A
  • fever
  • rigors
  • murmurs
  • palpable spleen (coxiella infection causes large liver/spleen)
  • clubbing
  • general fatigue
  • purpura
  • oslers nodes
  • janeway lesions (specific for endocarditis)

(viridans)

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9
Q

How is infective endocarditis diagnosed?

A

For definitive information on making a diagnosis, we have the Duke criteria. This divides symptoms into two categories; major and minor criteria

You can then assess whether IE is present or not.

IE definitely present:
2 major criteria present 
OR
1 major criteria, 3 minor criteria 
OR
5 minor criteria

IE possibly present:
1-4 minor criteria
AND
No other more likely diagnosis

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10
Q

What are dukes major criteria?

A

Positive blood culture for infective organisms (on 2 separate tests if >12 hours apart, or on 3/3 or 3/4 tests >1 hour apart)
-if blood culture is negative consider serology for atypicals

Evidence of IR from other tests:

  • Echocardiogram shows strictures, unusual blood flow, implanted /unusual material
  • Abscesses

New valve regurgitation

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11
Q

What are dukes minor criteria? 6

A

Fever >38’C

Predisposition to IE; e.g. IV drug user, congenital heart condition, prosthetic valve

Unusual echo, but not with findings stated above

Immunological factors present; Roth spots, Osler’s nodes, glomerulonephritis, rheumatoid factor

Blood cultures positive, but major criteria not satisfied

Vascular abnormalities; embolism, aneurysm, infarcts, conjunctival haemorrhage, intracranial haemorrhage etc

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12
Q

Describe the differences between transthoracic echocardiography and transoesophageal echocardiography?

A

TTE: rapid, non-invasive. high specificity but sensitivity only 60-70%. vegetations below 2mm easily missed.

TOE: echo via oesophagus. higher sensitivity 90%. identifies vegetations of 1mm and higher. better view of prosthetic heart valves

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13
Q

When is a TTE used in the diagnosis of infective endocarditis?

A

in everyone with native heart valves where there’s a clinical suspicion of IE

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14
Q

When is a TOE used in the diagnosis of infective endocarditis?

A

In those with a prosthetic heart valve

In those with a positive or non-diagnosis TTE

In those with a negative TTE but clinical suspicion is still high

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15
Q

How should blood cultures be taken when infective endocarditis is suspected?

A

3 sets of optimally filled blood cultures should be taken from peripheral sites
(does not require to be
different sites )
with ≥ 6 hours between them prior to commencing anti microbial therapy

severe sepsis or septic shock
at the time of presentation, 2 sets of optimally filled blood cultures should be taken at different times within 1 hour prior to commencement of empirical therapy,

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16
Q

Other than blood cultures what other general lab tests are important when suspecting infective endocarditis?

A

Full blood count- A normocytic, normochromic anaemia (anaemia of chronic disease) may be present, as are polymorphonuclear leucocytes.
Thrombocytopaenia (low platelet count) and thrombocytosis (high platelet count) are also common.

U+E- Renal dysfunction is common

LFT’s- ALP is likely to be raised, other values may be slightly abnormal

Inflammatory markers – CRP and ESR are likely to be raised. CRP is a more acute phase protein than ESR, and thus is more accurate and useful in monitoring progress.

Urine – proteinurea may occur, and microscopic haematuria is nearly always present

17
Q

What is the difference between the pathophysiology of infection in early (within 60days) and late presentations of prosthetic valve endocarditis?

A

Early- usually infected at time of valve insertion and usually due to Staphylococcus epidermidis or Staphylococcus aureus

Late - up to many years after valve insertion - due to co-incidental bacteraemia. Wide range of possible organisms

18
Q

What is the empirical treatment for infective endocarditis

  • native heart valve
  • prostetic heart valve
  • IVDU ?
A

Native = IV amoxicillin and gentamicin
(if penicillin allergic vancomycin and gentamicin)

Prosthetic valve endocarditis
Vancomycin & gentamicin IV
Add in day 3 to 5 (delayed) rifampicin PO
often valve replacement is required

Drug user endocarditis
Flucloxacillin IV
After that as guided by culture results

19
Q

What is the treatment for

  • S.Aureus (not-MRSA)
  • MRSA
  • strep. Viridans
  • enterococcus
  • s. epidermidis
A 
Staphylococcus aureus (not MSSA)
Flucloxacillin IV

MRSA treat as per prosthetic valve

Viridans streptococci
Benzylpenicillin iv & gentamicin iv (synergistic)

Enterococcus sp.
Amoxicillin/ vancomycin & gentamicin IV

Staphylococcus epidermidis
Vancomycin & gentamicin IV & rifampicin PO

20
Q

Describe the algorithm in identifying the organism for infective endocarditis?

A

If blood cultures are positive can do antimicrobial susceptability testing

if blood cultures are negative can do serologies and PCR, if then PCR is negative check anti-nuclear antibodies, anti-phospholipid antibodies and anti-pork antibodies

21
Q

What specific treatment is given for:

  • S. aureus
  • MRSA
  • Viridans streptococci
  • Enterococcus sp
  • staphylococcus epidermidis?
A 
Staphylococcus aureus (not MSSA)
Flucloxacillin IV

MRSA treat as per prosthetic valve

Viridans streptococci
Benzylpenicillin iv; gentamicin iv (synergistic)

Enterococcus sp.
Amoxicillin/ vancomycin; gentamicin IV

Staphylococcus epidermidis
Vancomycin IV , gentamicin IV, rifampicin PO

22
Q

in infective endocarditis:

How long is IV abiotics given for? what is important to monitor? what to do if failing on abiotics?

A

IV antibiotics usually given for 4 - 6 weeks

Monitor cardiac function, temperature and serum C-reactive protein (CRP)

If failing on antibiotic therapy, consider referral for surgery early

23
Q

what does OPAT mean in the management of infective endocarditis?

A

out patient abiotic therapy

24
Q

When is OPAT considered in the management of infective endocarditis?

A

Critical phase wks 0-2:

  • if oral strep. or strep bovis
  • AND if native valve/pt stable

Continuation phase wks 2+:

  • if medically stable
  • NOT if HF, echo is concern, neuro signs, renal impairment
25
Q

What are the symptoms 4 and signs 2 of myocarditis?

A

More common in young people (cause of sudden death)

Symptoms -fever, chest pain, shortness of breath, palpitations

Signs -arrythmia, cardiac failure

26
Q

What are the organisms that usually cause myocarditis?

A

Mainly caused by enteroviruses -Coxsackie A & B, echovirus, but other viruses possible the list is extensive.

27
Q

How is myocarditis diagnosed?

A

Diagnosed by viral PCR. Throat swab and stool for enteroviruses. Throat swab for influenza

28
Q

What is the treatment of myocarditis?

A

supportive

29
Q

What are the three outcomes of myocarditis?

A
  • Resolution
  • Autoimmune myocarditis: immune response remains active and ongoing myocardial injury
  • dilated cardiomyopathy: can occur after myocarditis or after autoimmune myocarditis - ongoing immun response and ongoing myocardial injury
30
Q

In pericarditis what is the main feature? what are two other clinical features? what is heard on auscultation?

A

characteristic chest pain (retrosternal, pleuritic, worse on lying flat, relieved by sitting forward), tachycardia and dyspnoea.

There may be an associated pericardial friction rub or evidence of a pericardial effusion.

31
Q

what is the aetiology of pericarditis?

A

viral mainly

  • post cardiothoracic surgery
  • rarely secondary spread from endocarditis or pneumonia
  • often occurs with myocarditis
32
Q

what is the treatment of pericarditis

A

supportive

if bacterial - drainage and abiotics

33
Q

what is seen on the ECG in pericarditis?

A

widespread concave ST elevation and PR depression throughout most of the limb leads (I, II, III, aVL, aVF) and precordial leads (V2-6).
Reciprocal ST depression and PR elevation in lead aVR (± V1).

Cardiology (17 decks)

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