infective endocarditis Flashcards
What is infective endocarditis?
infection involving the endocardial surface of the heart, inflammation
What side does infective endocarditis mostly affect?
left side
When would right sided infections occur?
from IV drug use
can it affect prosthetic valves and pacemaker leads
yes
common in older or younger people?
older
Why is IE more common in elderly now?
- change in RF - rheumatic heart disease is less common in high income countries, valvular disease more common in elderly
- inc age of the population
- healthcare associated - new Tx methods with catheters, cardiac devices, mostly affects the older population
RF for IE
- 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
pathophysiology of IE
- 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
What can cause bacteraemia?
mild mucosal trauma - dental, GI, urological, gynaecological procedures
also after brushing teeth, chewing
most common bacterial causes of IE
G+ve bacteria
Staphylooccus and streptococci common causes
fungi can cause it also
2 types of IE - classification
- acute IE
- subacute IE
acute IE onset and Sx
develops in days-weeks
spiking fevers
tachycardia
fatigue
progressive damage to cardiac structures
subacute IE onset and Sx
develops over weeks-months
Sx often vague - hard to diagnose
classification by location of infeciton
- native valve endocarditis (NVE)
- prostethetic valve endocarditis (PVE)
native valve endocarditis (NVE) - bacterial causes
absence of IV drugs - common with streptococci, enterococci, stpahylococci
IV drug users - S aureus, streptococci, G-ve bacilli often with right sided valvular involvement
prosthetic valve endocarditis (PVE)
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)
Sx of acute IE
- 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
presentation of subacute IE
- 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
Janeway lesions
red painless, palms/soles
Roth spots
retinal lesions surrounded by haemorrhage
Osler nodes
small painful lesions on fingers/toes
diagnosis of IE
no single clinical test result
combination of clinical, microbiological and echocardiography findings
2 criteria:
1. modified Duke criteria
2. ESC - European sociaty cardiology
When is Duke criteria less sensitive?
- early diagnostics
- prosthetic valve endocarditis and pacemaker/defribilaror lead IE
investigations for IE
blood cultures
ECHO
FBC
CRP
U&Es
blood glucose
LFTs
urinalysis
ECG
consider:
- rheumatoid factor/other immunological blood tests
- ESR
- complement levels
- CT
- MRI
When/how should blood cultures be taken for IE?
3 sets should be taken at 30min intervals
before starting antimicrobial Tx
types of Tx for IE
antimicrobial drugs
surgery - remove infected material, drain abscess
antimicrobial drug Tx
- based on sensitivity to ID pathogen
- combination more effective than bacteriostatic therapy
- tolerance is barrier to effective Tx
- prolonged courses required
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
What are gentamicin doses based on?
serum gentamicin concentration
When is post dose/peak levels of gentamicin taken?
1 hour after injection
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
How often is gentamicin given if multiple daily dosing?
3 divided doses, every 8hrs
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
peak/post-dose levels for gentamicin
3-5 mg/L
trough/pre-dose levels for gentamicin
< 1 mg/L
What to do if trough/pre-dose levels of gentamicin are high?
inc the interval between doses
What to do if peak/post-dose levels of gentamicin are high?
dose must be decreased
monitoring for gentamicin
renal fxn
s/e of gentamicin
nephrotoxicity
ototoxicity
GI effects
infusion rxns
When are vancomycin levels taken?
on 2nd day of Tx immediately before the next dose if renal fxn normal
earlier if renal impairment
Route of vancomycin for systemic infections?
parenteral
oral not effective for systemic infections
s/e of vancomycin
nephrotoxicity
ototoxicity
hypersensitivity reactions - red man syndrome, anaphylaxis
When would surgery be used to manage IE?
high risk patients
* HF or high risk of HF
* uncontrolled infection
* high embolic risk
What must be started before surgery?
antimicrobial therapy
patients that would have a poorer outcome
- older age
- prosthetic valve IE
- DM
- co-morbidity (frailty, immunosuppression)
- HF
- renal failure
- sepsis
- S. aureus
- fungi
complications of IE
- acute HF
- systemic embolism (stroke)
- AKI
- mitral valve vegetation >10mm
When should prophylaxis be used for IE?
ONLY for high risk patients if undergoing invasive procedures or dental work
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
highest risk patients
- prosthetic valve
- Hx of IE
- CHD
prophylaxis for dental procedures for at risk patients
amoxicillin/ampicillin
clindamycin - pen allergic
