infective endocarditis Flashcards

1
Q

What is infective endocarditis?

A

infection involving the endocardial surface of the heart, inflammation

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2
Q

What side does infective endocarditis mostly affect?

A

left side

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3
Q

When would right sided infections occur?

A

from IV drug use

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4
Q

can it affect prosthetic valves and pacemaker leads

A

yes

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5
Q

common in older or younger people?

A

older

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6
Q

Why is IE more common in elderly now?

A
  1. change in RF - rheumatic heart disease is less common in high income countries, valvular disease more common in elderly
  2. inc age of the population
  3. healthcare associated - new Tx methods with catheters, cardiac devices, mostly affects the older population
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7
Q

RF for IE

A
  • any structural heart disease
  • rheumatic heart disease (damage to heart valves after rheumatic fever - untreated streptococcal infection, strep throat, scarlet fever), affects mitral valve (less common)
  • prosthetic valves and cardiac devices (common in older)
  • congenital heart disease (mitral valve prolapse)
  • hypertrophic cardiomyopathy
  • IV drug use
  • immunosuppression (HIV)
  • extensive healthcare system contact
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8
Q

pathophysiology of IE

A
  • endothelial damage on valves of the heart
  • platelets and fibrin adhere to underlying collagen surface
  • bacteraemia leads to colonisation of this thrombus, leads to deposition of fibrin and aggregation of platelets
  • develops in to a mature infected vegetation
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9
Q

What can cause bacteraemia?

A

mild mucosal trauma - dental, GI, urological, gynaecological procedures

also after brushing teeth, chewing

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10
Q

most common bacterial causes of IE

A

G+ve bacteria

Staphylooccus and streptococci common causes

fungi can cause it also

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11
Q

2 types of IE - classification

A
  1. acute IE
  2. subacute IE
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12
Q

acute IE onset and Sx

A

develops in days-weeks

spiking fevers

tachycardia

fatigue

progressive damage to cardiac structures

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13
Q

subacute IE onset and Sx

A

develops over weeks-months

Sx often vague - hard to diagnose

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14
Q

classification by location of infeciton

A
  1. native valve endocarditis (NVE)
  2. prostethetic valve endocarditis (PVE)
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15
Q

native valve endocarditis (NVE) - bacterial causes

A

absence of IV drugs - common with streptococci, enterococci, stpahylococci

IV drug users - S aureus, streptococci, G-ve bacilli often with right sided valvular involvement

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16
Q

prosthetic valve endocarditis (PVE)

A

up to 30% of IE cases

if within 1 year of implant = early PVE, S aureus common or coagulase -ve staphylococci

> 1yr = late PVE (same organisms as NVE)

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17
Q

Sx of acute IE

A
  • peripheral/central emboli or evidence of decompensated congestive HF
  • fever + headache, meningitis Sx, stroke Sx, chest pain, dyspnoea on exertion, orthopnoea, paroxysmal nocturnal dyspnoea -> evaluate for IE
  • peripheral septic emboli can cause arthralgias or back pain
  • rapid disease process, so immunological features not seen
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18
Q

presentation of subacute IE

A
  • Sx less specific
  • fever, chills
  • night sweats, malaise, fatigue, anorexia, weight loss, myalgias
  • palpitations
  • immunological findings more likely to be seen
    -> Janeway lesions (red painless, palms/soles), Osler nodes (small painful lesions on fingers/toes), splinter haemorrhages, cutaneous infarcts
    -> palatal petechiae
    -> Roth spots (retinal lesions surrounded by haemorrhage)
    -> finger clubbing (indicates diff things)
  • diff diagnosis of patient with progressive fever and continual Sx
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19
Q

Janeway lesions

A

red painless, palms/soles

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20
Q

Roth spots

A

retinal lesions surrounded by haemorrhage

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21
Q

Osler nodes

A

small painful lesions on fingers/toes

22
Q

diagnosis of IE

A

no single clinical test result

combination of clinical, microbiological and echocardiography findings

2 criteria:
1. modified Duke criteria
2. ESC - European sociaty cardiology

23
Q

When is Duke criteria less sensitive?

A
  • early diagnostics
  • prosthetic valve endocarditis and pacemaker/defribilaror lead IE
24
Q

investigations for IE

A

blood cultures
ECHO
FBC
CRP
U&Es
blood glucose
LFTs
urinalysis
ECG

consider:
- rheumatoid factor/other immunological blood tests
- ESR
- complement levels
- CT
- MRI

25
When/how should blood cultures be taken for IE?
3 sets should be taken at 30min intervals before starting antimicrobial Tx
26
types of Tx for IE
antimicrobial drugs surgery - remove infected material, drain abscess
27
antimicrobial drug Tx
- based on sensitivity to ID pathogen - combination more effective than bacteriostatic therapy - tolerance is barrier to effective Tx - prolonged courses required
28
challenges of IE Tx
- delayed and inappropriate ABX therapy has worse outcomes for patients - prompt initiation of Tx after sampling best - starting Tx before culture sample and give -ve cultures
29
What are gentamicin doses based on?
serum gentamicin concentration
30
When is post dose/peak levels of gentamicin taken?
1 hour after injection
31
Advantage of using once daily dosing for gentamicin
- high peaks are more effective in achieving bacterial kill - long PAE, don't need to have levels above MIC - lower trough levels associated with reduced toxicity, dec risk of nephrotoxicity and ototoxicity - monitoring is simpler - less time needed for admin
32
How often is gentamicin given if multiple daily dosing?
3 divided doses, every 8hrs
33
When should serum concs be taken for multiple daily dosing of gentamicin?
after 3 or 4 doses then at least every 3 days and after a dose change more frequently in renal impairment
34
peak/post-dose levels for gentamicin
3-5 mg/L
35
trough/pre-dose levels for gentamicin
< 1 mg/L
36
What to do if trough/pre-dose levels of gentamicin are high?
inc the interval between doses
37
What to do if peak/post-dose levels of gentamicin are high?
dose must be decreased
38
monitoring for gentamicin
renal fxn
39
s/e of gentamicin
nephrotoxicity ototoxicity GI effects infusion rxns
40
When are vancomycin levels taken?
on 2nd day of Tx immediately before the next dose if renal fxn normal earlier if renal impairment
41
Route of vancomycin for systemic infections?
parenteral oral not effective for systemic infections
42
s/e of vancomycin
nephrotoxicity ototoxicity hypersensitivity reactions - red man syndrome, anaphylaxis
43
When would surgery be used to manage IE?
high risk patients * HF or high risk of HF * uncontrolled infection * high embolic risk
44
What must be started before surgery?
antimicrobial therapy
45
patients that would have a poorer outcome
* older age * prosthetic valve IE * DM * co-morbidity (frailty, immunosuppression) * HF * renal failure * sepsis * S. aureus * fungi
46
complications of IE
* acute HF * systemic embolism (stroke) * AKI * mitral valve vegetation >10mm
47
When should prophylaxis be used for IE?
ONLY for high risk patients if undergoing invasive procedures or dental work
48
prevention of IE
* ABX prophylaxis in high risk patients * good dental hygiene, regular reviews * disinfection of wounds * aspetic measures during invasive procedures * no self medication with ABX * piercing and tattooing - discourage * limit catheters - peripheral > central
49
highest risk patients
- prosthetic valve - Hx of IE - CHD
50
prophylaxis for dental procedures for at risk patients
amoxicillin/ampicillin clindamycin - pen allergic