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Cardiovascular > Cardiac infections > Flashcards

Cardiac infections Flashcards

1
Q

What is bacteremia?

A

The presence of bacteria in the blood stream

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2
Q

Blood is normally a sterile site. T of F?

A

True

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3
Q

What colour is a positive and negative blood culture bottle?

A

Blue is negative

Orange is positive

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4
Q

What happens to positive blood cultures?

A

Plated and grown in cluture

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5
Q

What is infective endocarditis?

A

Infection of endothilium of heart valves.

Can be acute or sub acute but usually classified by organism.

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6
Q

Why does infective endocarditis have a high mortality?

A

Diagnosed late 25% mortality

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7
Q

How frequently does infective endocarditis occur?

A

1 in 1000 hospital admissions (mostly over 50 yrs)

Hospital acquired cases increasing due to S aureus

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8
Q

What are the predisposing factors for infective endocarditis?

A

Heart valve abnormality (increases turbulence
- Calcification/sclerosis, congenital heat disease, post rheumatic fever
Prosthetic heart valve (biofilms on surface)
IV drug abusers (impurities cause turbulence, needle lickers)
IV lines (portal to the outside world)

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9
Q

What is the pathogenisis of infective endocarditis?

A

1) Heart valve damage and turbulent blood flow over epithilium
2) Platelets and fibrin deposited => inflammation
3) Bactereamis (maybe transient) organisms settle on fibrin/platelet thrombi => Microbial vegetation (different organisms= different growth factors
4) Infected vegitations can embolise causin haemorrhage or abscesses in distal sites

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10
Q

Where does infective endocarditis usually occur?

A

Left side of heart- aortic and mitral valves.

Except in PWID and then tricuspid is most common

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11
Q

What are the common causative organisms of infective endocarditis?

A 
Staph aureus (38%) Gram + cocci clusters
Strep Viridans (31%) Gram + cocci chains (alpha haemolysis)
Enterococcus sp (8%)
Staph epidermidis (6%) Gram + cocci clusters
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12
Q

What are the atypical organisms causing infective endocarditis?

A

Bartonella, Coxiella burnetti (q fever), Chlamydia, legionella, mycoplasma, brucella

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13
Q

Atypical organisms don’t culture well. How are they identified?

A

Serum antibodies

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14
Q

What are the gram negative organisms causing infective endocarditis?

A 
HACEK organisms (Haemophylus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella.
Non HACEK gram negatives
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15
Q

What happens if you suspect a HACEK organism to be the cause?

A

Hold blood cultures for 7-14 days (normally just 5)

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16
Q

Can fungi cause infective endocarditis?

A

Yes- hard to culture

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17
Q

What are the major criteria for the modified dukes criteris?

A

1) 2 separate positive blood cultures with microorganisms typical for infective endocarditis (S. viridans, S. bovis, HACEK group, S. aureus, Community acquired enterococci)
2) Echo evidence of endocardial involvement. typical valvular legions: vegetation, abscess, new partial dehisence of a prosthetic valve
3) New valvular regurgitation

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18
Q

What are the minor criteria of the modified dukes criteria?

A

1) Predisposition: Heart condition or IV drug use
2) Temperature >38 degrees
3) Vascular phenomenon: arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intercranial/conjunctival haemorrhage, janeway lesions
4) Immunological phenomena: Glomerulonephritis, Oslers nodes, Roth spots, Rheumatoid factor
5) Microbiological evidence: positive blood culture not meeting major criteria, or serological evidence of active infection with organism consistent with infective endocarditis

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19
Q

What are the investigations for infective endocarditis?

A

1) TTE: Transthroacic echocardiogram (if negative but high clinical suspicion continue to 2))
2) TOE: Transosophageal echocardiogram
- If negative but still unwell, repeat in 5-7 days

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20
Q

What is the most common coagulase negative Staph organism?

A

Staph epidermidis

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21
Q

Staph epidermidis is often a skin contaminant so where is it likely to infect?

A

Prosthetic material

IV lines, prosthetic heart valves and joints

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22
Q

What are diphtheriods?

A

Skin contaminants

Gram + bacilli

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23
Q

What are the presenting symptoms of acute infective endocarditis?

A

Overwhelming sepsis and cardiac failure

Usually aggressive virulent organism like S aureus

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24
Q

What are the presenting symptoms of subacute infective endocarditis?

A

Fever, malaise, weightloss, tiredness, breathless
Less virulent organism eg strep viridans
Can be infected for 3 months

25
Q

What are the presenting signs of infective endocarditis?

A

Fever
New/changing murmur
Microscopic haematurea
Sub acute: finger clubbing, spleenomegaly, Roth spots, Osler’s nodes, Janeway Lesions

26
Q

What is a roth spot?

A

Little white spot on the retina

27
Q

What is a janeway lesion?

A

Nodules on palms and souls of feet

28
Q

What are Osler’s nodes?

A

Small red painful spot on the hands and feet

29
Q

Where is viridans group strep usually found?

A

Oral commensal

30
Q

What are the characteristics of Vididans group strep?

A

Alpha haemolytic gram positive cocci in chain
Cause sub acute endocarditis
No lansfield group

31
Q

What organisms are within the strep viridans group?

A

Strep. mitis, Strep. songuinis, Strep. mutans, Strep. salivaris

32
Q

What is required to diagnose infective endocarditis?

A

3 sets of blood cultures before antibiotics at least 1 hr apart (acute) or 6hrs apart (subacute)
This helps to rule out a contaminant
Possibly follow up with a transthoracic echo, then transoesophageal echo if required

33
Q

What happens if the blood culture is negative?

A

Consider serology for atypical organisms

34
Q

What is the treatment for prosthetic valve endocarditis?

A

IV vancomycin, IV gentamycin + PO Rifampicin 3-5 after treatment initiation

35
Q

What are the 2 presentations of prosthetic valve endocarditis?

A

Early presentation: within 60 days of valve replacement. INfected at time of insertion usually with S. aureus or S. epidermidis
Late presentation: Many years after insertion. Due to coincidental bacteramia and caused by a wide range of organisms

36
Q

What are the characteristics of endocarditis in a PWID?

A

Right sided- often tricuspid valve
Usually S aureus
Septic pulmonary emboli are common
Often normal valve

37
Q

What is the emperical treatment for endocarditis in a PWID?

A

IV flucloxacillin and penicillin allergic give vancomycin

38
Q

What is the emperical treatment for native valveendocarditis (ofen causes by viridans strep)?

A

IV Amoxicillin and IV gentamycin

39
Q

What is the treatment for endocarditis caused by Staph aureus?

A

IV flucloxacillin

40
Q

What is the treatment for endocarditis caused by MRSA?

A

IV Vancomycin, IV gentamycin and PO Rifampacin

41
Q

What is the treatment for endocarditis caused by viridans strep?

A

IV Benzylpenicillin and IV gentamycin

42
Q

What is the treatment for endocarditis caused by enterococcus species?

A

IV amoxicillin/vancomycin

IV gentamycin

43
Q

What is the treatment for endocarditis caused by S. epidermidis?

A

IV Vancomycin, IV gentamycin and PO ripampacin 3-5 days after initiating treatment

44
Q

How long should IV antibiotics be given for in endocarditis?

A

4-6 weeks

45
Q

What should be monitored while someone is being treated for endocarditis?

A

Cardiac function, temperature and CRP

46
Q

WHat happens if antibiotics seam to be ineffective?

A

Consider referral for surgery early

47
Q

What is the prognosis for endocarditis and what is this dependant on?

A

Mortality is 15-30% and is dependant on 4 catogaries of risk:

1) Patient characteristics
2) Clinical complications of IE
3) Microorganism (S aureus, fungi, non HACEK gram negatives are all bad)
4) Echo findings

48
Q

When can OPAT be used?

A

Outpatient Parentral Antibiotic therapy

Certain patients after 2 weeks of inpatient therapy

49
Q

What is myocarditis?

A

Inflamation of the heart muscle

50
Q

Which population group is myocarditis more common?

A

Young people- cause of sudden cardiac death

51
Q

What are the symptoms of myocarditis?

A

Fever, chest pain, SOB, Palpitations

52
Q

What are the signs of myocarditis?

A

Arrhythmia and cardiac failure

53
Q

What are teh causes of myocarditis?

A

Mainly entero virus’: Coxackie A and B and echovirus

54
Q

How is myocarditis diagnosed?

A

Viral PCR
Throat swab and stool for enterovirus
Throat swab for influenza

55
Q

What is the treatment for myocarditis?

A

Supportive

56
Q

What is pericarditis?

A

Inflamation of the pericardium

57
Q

What are the symptoms of pericarditis?

A

Chest pain

58
Q

What are the causes of pericarditis?

A

Viral mainly, bacteria less common

eg post cardiothoracic surgery, rarely secondary spread from endocarditis or pneumonia

59
Q

What is the treatment for pericarditis?

A 
Viral = supportive
Bacterial = Antibiotics and drainage

Cardiovascular (24 decks)

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