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
Q

When/how should blood cultures be taken for IE?

A

3 sets should be taken at 30min intervals

before starting antimicrobial Tx

26
Q

types of Tx for IE

A

antimicrobial drugs

surgery - remove infected material, drain abscess

27
Q

antimicrobial drug Tx

A
  • based on sensitivity to ID pathogen
  • combination more effective than bacteriostatic therapy
  • tolerance is barrier to effective Tx
  • prolonged courses required
28
Q

challenges of IE Tx

A
  • 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
Q

What are gentamicin doses based on?

A

serum gentamicin concentration

30
Q

When is post dose/peak levels of gentamicin taken?

A

1 hour after injection

31
Q

Advantage of using once daily dosing for gentamicin

A
  • 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
Q

How often is gentamicin given if multiple daily dosing?

A

3 divided doses, every 8hrs

33
Q

When should serum concs be taken for multiple daily dosing of gentamicin?

A

after 3 or 4 doses

then at least every 3 days and after a dose change

more frequently in renal impairment

34
Q

peak/post-dose levels for gentamicin

A

3-5 mg/L

35
Q

trough/pre-dose levels for gentamicin

A

< 1 mg/L

36
Q

What to do if trough/pre-dose levels of gentamicin are high?

A

inc the interval between doses

37
Q

What to do if peak/post-dose levels of gentamicin are high?

A

dose must be decreased

38
Q

monitoring for gentamicin

A

renal fxn

39
Q

s/e of gentamicin

A

nephrotoxicity
ototoxicity
GI effects
infusion rxns

40
Q

When are vancomycin levels taken?

A

on 2nd day of Tx immediately before the next dose if renal fxn normal

earlier if renal impairment

41
Q

Route of vancomycin for systemic infections?

A

parenteral

oral not effective for systemic infections

42
Q

s/e of vancomycin

A

nephrotoxicity
ototoxicity
hypersensitivity reactions - red man syndrome, anaphylaxis

43
Q

When would surgery be used to manage IE?

A

high risk patients
* HF or high risk of HF
* uncontrolled infection
* high embolic risk

44
Q

What must be started before surgery?

A

antimicrobial therapy

45
Q

patients that would have a poorer outcome

A
  • older age
  • prosthetic valve IE
  • DM
  • co-morbidity (frailty, immunosuppression)
  • HF
  • renal failure
  • sepsis
  • S. aureus
  • fungi
46
Q

complications of IE

A
  • acute HF
  • systemic embolism (stroke)
  • AKI
  • mitral valve vegetation >10mm
47
Q

When should prophylaxis be used for IE?

A

ONLY for high risk patients if undergoing invasive procedures or dental work

48
Q

prevention of IE

A
  • 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
Q

highest risk patients

A
  • prosthetic valve
  • Hx of IE
  • CHD
50
Q

prophylaxis for dental procedures for at risk patients

A

amoxicillin/ampicillin

clindamycin - pen allergic