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Year 3 > Infective endocarditis (CV) > Flashcards

Infective endocarditis (CV) Flashcards

1
Q

Define infective endocarditis.

A

Infection of the endocardium (including valvular structures, chordae tendineae, sites of septal defects or the mural endocardium) that typically affects one or more heart valves

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2
Q

Which groups is infective endocarditis most common in? (2)

A
  • M>F
  • > 60 years old
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3
Q

List the valves in the order of likeliness of being affected in infective endocarditis from most to least.

A

MATP

  • mitral
  • aortic
  • tricuspid (but most likely affected in IVDU)
  • pulmonary
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4
Q

Which valve is most likely affected in IVDU-infective endocarditis?

A

Tricuspid valve

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5
Q

What is the pathophysiology of infective endocarditis?

A
  • vegetations (platelets, fibrin, infective organisms) form when organisms deposit on the valves during a period of bacteraemia
  • they destroy valve leaflets, invade myocardium or aortic wall –> abscess cavities
  • activation of the immune system can lead to formation of immune complexes –> vasculitis, glomerulonephritis, arthritis
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6
Q

Describe the course of infective endocarditis.

A

Follows an acute course, presenting with acute heart failure +/- emboli

(Can also be subacute)

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7
Q

What is the most common causative agent of acute infective endocarditis?

A

Staphylococcus aureus

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8
Q

List risk factors for infective endocarditis caused by S. aureus. (2)

A
  • patients with prosthetic valves
  • IV drug use
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9
Q

What is commonly the causative agent of infective endocarditis if <2 months post-valve surgery?

A

Staphylococcus epidermidis

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10
Q

What is the most common causative agent of subacute infective endocarditis?

A

Streptococcus viridans (a-haemolytic) - mainly affects pre-damaged native valves, commonly caused by dental procedures

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11
Q

What is commonly the causative agent of infective endocarditis associated with GI malignancy?

A

Streptococcus bovis

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12
Q

What is atrial myxoma (differential to infective endocarditis)?

A

Benign tumour most common in LA - presence of mass on echocardiogram distinguishes it from IE

  • mitral valve obstruction (mid-diastolic murmur)
  • systemic embolisation
  • constitutional symptoms
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13
Q

What are the clinical features of infective endocarditis? (8)

A
  • fever/chills
  • new cardiac murmur
  • dyspnoea on exertion
  • night sweats, malaise, fatigue, anorexia, weight loss, myalgias
  • weakness
  • arthralgias
  • headache
  • skin lesions
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14
Q

What may you find on examination in infective endocarditis? (10)

A
  • embolic phenomena:
    • splinter haemorrhages (under fingernails)
    • Janeway lesions (painless macule on palms and soles, blanch)
  • vasculitic lesions due to immune complex depositions:
    • Osler nodes (painful nodules on finger/toe pads)
    • Roth spots (white centred retinal haemorrhage on fundoscopy caused by septic emboli)
    • petechiae on pharyngeal and conjunctival mucosa
    • glomerulonephritis
  • new cardiac murmur (MATP)
  • pyrexia + tachycardia
  • clubbing
  • signs of anaemia
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15
Q

What acronym can we use to remember the signs of infective endocarditis?

A

FROM JANE C:

  • Fever
  • Roth spots
  • Osler nodes
  • Murmur
  • Janeway lesions
  • Anaemia
  • Nail - splinter haemorrhages
  • Emboli
  • Clubbing
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16
Q

What are some risk factors for infective endocarditis? (6)

A
  • prosthetic heart valves
  • abnormal heart valves (e.g. congenital, calcification, rheumatic heart disease)
  • dental procedures (/hygiene)
  • IV drug use (more likely to present with right-sided valve problems)
  • structural congenital heart disease
  • turbulent blood flow
17
Q

What are the first-line investigations for infective endocarditis? (4)

A
  • blood cultures
  • echocardiography (transthoracic first-line, transoesophageal better image)
  • FBC
  • CRP
18
Q

What do we do before commencing Abx therapy for infective endocarditis?

A
  • obtain 3 sets of blood cultures from different sites at 30-minute intervals prior to Abx initiation
  • if patients is very unwell do not delay empirical Abx therapy while waiting to take 3 sets
  • repeat 4-72h after treatment to assess effectiveness
19
Q

What is the most sensitive diagnostic test for infective endocarditis?

A
  • transthoracic echo - valvular, mobile vegetations
  • do transoesophageal echo (better image) if:
    • prosthetic valve/intracardiac device
    • transthoracic echo comes back negative
20
Q

What would FBC show in infective endocarditis?

A

High neutrophils, normocytic anaemia

21
Q

What might ECG show in infective endocarditis? (3)

A
  • prolonged PR interval
  • non-specific ST/T wave abnormalities
  • AV block
22
Q

What diagnostic criteria is used for infective endocarditis?

A

Duke criteria for infective endocarditis:

  • definitive diagnosis: 2 majors OR 1 major+3 minor OR 5 minor
  • possible diagnosis: 1 major+1 minor OR 3 minor
23
Q

What acronym helps us remember the major and minor Duke criteria for infective endocarditis?

A

BE TIMER

24
Q

What are the major Duke criteria for infective endocarditis? (2)

A

BE (TIMER)

  • Blood culture positive >/=2 times 12hrs apart for typical microorganism consistent with IE, or single positive culture for Coxiella burnetti or positive antibody titre
  • Echocardiogram +ve for IE - vegetation, abscess, partial dehiscence of prosthetic valve, new valvular regurgitation
    • (PET-CT shows abnormal activity around site of prosthetic valve)
    • (cardiac CT shows paravalvular lesions)
25
Q

What are the minor Duke criteria for infective endocarditis? (5)

A

(BE) TIMER

  • Temperature >38C (fever)
  • Immunological phenomena - Osler’s nodes, Roth spots, RF, glomerulonephritis
  • Microbiological evidence - blood culture not meeting major criteria, serological evidence of active infection with organism consistent with IE
  • Embolic (vascular) phenomena - arterial/septic emboli, infarcts, intracranial/conjunctival/splinter haemorrhages, Janeway lesions
  • Risk factors - predisposing heart condition or IVDU
26
Q

What signs on echocardiogram indicate infective endocarditis (major Duke criteria)? (4)

A
  • vegetation
  • abscess
  • partial dehiscence of prosthetic valve
  • new valvular regurgitation
27
Q

What are some immunological phenomena seen in infective endocarditis (minor Duke criteria)? (4)

A
  • Osler’s nodes
  • Roth spots
  • rheumatoid factor
  • glomerulonephritis
28
Q

What are some embolic phenomena seen in infective endocarditis (minor Duke criteria)? (4)

A
  • arterial/septic emboli
  • infarcts
  • intracranial/conjunctival/splinter haemorrhages
  • Janeway lesions
29
Q

What are some differential diagnoses for infective endocarditis? (4)

A
  • rheumatic fever
  • atrial myxoma - waxing and waning symptoms, echo shows mass, mid-diastolic murmur
  • Libman-Sacks endocarditis - asymptomatic, autoantibody profile
  • non-bacterial thrombotic endocarditis - produced by tumours, underlying hypercoagulable state
30
Q

How do you manage suspected infective endocarditis?

A
  • supportive care (fluids + O2) AND
  • blood cultures first AND
  • broad-spectrum (empirical) Abx: benzylpenicillin, gentamicin
    • native valve: amoxicillin +/- gentamicin
    • if penicillin allergic/MRSA/severe sepsis: vancomycin + gentamicin
    • prosthetic valve: vancomycin + gentamycin + rifampicin
  • consider valve replacement surgery if IE causing congestive HF
31
Q

What Abx is used for S. aureus infective endocarditis, if patient has a native valve?

A

Flucloxacillin

If penicillin allergic/MRSA - vancomycin + rifampicin

32
Q

What Abx is used for S. aureus infective endocarditis, if patient has a prosthetic valve?

A

Flucloxacillin + low-dose gentamicin + rifampicin

If penicillin allergic/MRSA - replace flucloxacillin with vancomycin

33
Q

What Abx is used for Staphylococcus epidermidis infective endocarditis?

A

Vancomycin - since coagulase -ve Staphylococci are resistant to flucloxacillin

34
Q

What Abx is used for Streptococcus viridans (or other fully-sensitive Streptococci) infective endocarditis?

A

Benzylpenicillin

(Add low-dose gentamicin if less sensitive Streptococci)

If penicillin-allergic: vancomycin + low-dose gentamicin

35
Q

What are some indications for urgent valvular replacement (surgery) in infective endocarditis? (6)

A
  • PR interval prolongation - indicates aortic abscess
  • severe valvular incompetence
  • infections resistant to Abx/fungal infections
  • cardiac failure refractory to standard medical treatment (severe congestive HF)
  • recurrent emboli after Abx therapy
  • pregnancy
36
Q

What are some complications of infective endocarditis? (8)

A
  • valve incompetence
  • intracardiac fistulae/abscesses
  • aneurysm
  • heart failure
  • renal failure
  • glomerulonephritis
  • splenic abscess
  • arterial emboli from vegetations breaking off –> brain (ischaemic stroke), kidneys, lung, spleen
37
Q

What is the best indicator of prognosis in infective endocarditis?

A

Heart failure

Year 3 (203 decks)

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