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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
What are the presenting signs of infective endocarditis?
Fever New/changing murmur Microscopic haematurea Sub acute: finger clubbing, spleenomegaly, Roth spots, Osler's nodes, Janeway Lesions
26
What is a roth spot?
Little white spot on the retina
27
What is a janeway lesion?
Nodules on palms and souls of feet
28
What are Osler's nodes?
Small red painful spot on the hands and feet
29
Where is viridans group strep usually found?
Oral commensal
30
What are the characteristics of Vididans group strep?
Alpha haemolytic gram positive cocci in chain Cause sub acute endocarditis No lansfield group
31
What organisms are within the strep viridans group?
Strep. mitis, Strep. songuinis, Strep. mutans, Strep. salivaris
32
What is required to diagnose infective endocarditis?
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
What happens if the blood culture is negative?
Consider serology for atypical organisms
34
What is the treatment for prosthetic valve endocarditis?
IV vancomycin, IV gentamycin + PO Rifampicin 3-5 after treatment initiation
35
What are the 2 presentations of prosthetic valve endocarditis?
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
What are the characteristics of endocarditis in a PWID?
Right sided- often tricuspid valve Usually S aureus Septic pulmonary emboli are common Often normal valve
37
What is the emperical treatment for endocarditis in a PWID?
IV flucloxacillin and penicillin allergic give vancomycin
38
What is the emperical treatment for native valveendocarditis (ofen causes by viridans strep)?
IV Amoxicillin and IV gentamycin
39
What is the treatment for endocarditis caused by Staph aureus?
IV flucloxacillin
40
What is the treatment for endocarditis caused by MRSA?
IV Vancomycin, IV gentamycin and PO Rifampacin
41
What is the treatment for endocarditis caused by viridans strep?
IV Benzylpenicillin and IV gentamycin
42
What is the treatment for endocarditis caused by enterococcus species?
IV amoxicillin/vancomycin | IV gentamycin
43
What is the treatment for endocarditis caused by S. epidermidis?
IV Vancomycin, IV gentamycin and PO ripampacin 3-5 days after initiating treatment
44
How long should IV antibiotics be given for in endocarditis?
4-6 weeks
45
What should be monitored while someone is being treated for endocarditis?
Cardiac function, temperature and CRP
46
WHat happens if antibiotics seam to be ineffective?
Consider referral for surgery early
47
What is the prognosis for endocarditis and what is this dependant on?
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
When can OPAT be used?
Outpatient Parentral Antibiotic therapy | Certain patients after 2 weeks of inpatient therapy
49
What is myocarditis?
Inflamation of the heart muscle
50
Which population group is myocarditis more common?
Young people- cause of sudden cardiac death
51
What are the symptoms of myocarditis?
Fever, chest pain, SOB, Palpitations
52
What are the signs of myocarditis?
Arrhythmia and cardiac failure
53
What are teh causes of myocarditis?
Mainly entero virus': Coxackie A and B and echovirus
54
How is myocarditis diagnosed?
Viral PCR Throat swab and stool for enterovirus Throat swab for influenza
55
What is the treatment for myocarditis?
Supportive
56
What is pericarditis?
Inflamation of the pericardium
57
What are the symptoms of pericarditis?
Chest pain
58
What are the causes of pericarditis?
Viral mainly, bacteria less common | eg post cardiothoracic surgery, rarely secondary spread from endocarditis or pneumonia
59
What is the treatment for pericarditis?
``` Viral = supportive Bacterial = Antibiotics and drainage ```

Cardiovascular (24 decks)

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