Wk 33: Infective endocarditis Flashcards
Which side of the heart does infective endocarditis usually affect?
Left side
- Right: IV drug abuse
What are the risk factors of infective endocarditis?
- Rheumatic + congenital HD
- Prosthetic valves + cardiac devices
- Injection drug use
- Immunosuppression
What is the pathophysiology of infective endocarditis?
- Endothelial damage on valve of heart
- Platelet + fibrin adhere to underlying collagen surface
- Bacteremia = colonisation of thrombus, further deposition of fibrin + platelet aggregation
- Develops into mature infected vegetation
What is the most common cause of IE?
- Viridans group streptococci
- Staph a
What is acute infective endocarditis?
Days + wks:
- Fever w/ headache
- Stroke symptoms
- Chest + back pain
- Dyspnoea on exertion
What are the 2 classifications of IE based on the location?
- Native valve endocarditis
- Prosthetic valve endocarditis
What is native valve endocarditis?
- Absence of IV drugs: viridian group strept
- IV drug use: staph a
What is prosthetic valve endocarditis?
- W/in 1 yr if implantation: early PVE (staph a or coagulase -ve staph)
- After 1 yr: late PVE
What are the symptoms of subacute IE?
Less specific:
- Fever, chill
- Night sweats
- Fatigue
- WL
- Splinter haemorrhage, osler nodes, roth spots, janeway lesions
- Clubbing
How is IE diagnosed?
- Clinical, microbiology + echocardiography
- Modified duke criteria
- European society cardiology criteria
What is the problem with the modified duke criterias?
Lower accuracy: prosthetic valve endocarditis, pacemaker or defib
What investigations are needed to diagnose IE?
- Blood cultures
- Echocardiography
- FBC, CRP, U+E, LFTs
- Urinalysis
- ECG
What investigation can be considered to diagnose IE?
- Rheumatoid factor
- ESR
Tomography
- MRI
How are blood cultures taken?
3 sets, 30 min intervals before starting antimicrobial treatment
What is the treatment for IE?
- Bactericidal combination
- Surgery - remove infection + drain abscess (start antimicrobial)
What are the important points for taking gentamicin multiple daily dosing?
- 3 divided dose (every 8 hrs)
- Measure conc after 3/4 doses then every 3 days + after dose change
- Post dose: 1 hr after dose 3-5mg/l (if high dec dose)
- Pre-dose: <1mg/L (if high inc dose interval)
What are the side effects of gentamicin?
- Nephrotoxicity
- Ototoxicity
- GI effects
- Infusion reactions
When do you measure the conc of vancomycin?
2nd day of treatment
What are the s/e of vancomycin?
- Nephrotoxicity
- Ototoxicity
- Hypersensitivity
What are predictors of poor outcome?
- Old age
- Prosthetic valve IE
- Diabetes
- HF
- Renal failure
- Staph a + fungi
What are the complications of IE?
- Acute HF
- Systemic embolism
- AKI
- Splenic abscess
What are the counselling points to avoid IE?
- Strict dental hygiene: follow up twice a year
- Disinfect wounds
- Discourage piercings + tattooing
- Limit infusion catheters
Which patients are classed high risk for prophylaxis treatment?
- Prosthetic valve
- Previous IE
- CHD
What is the prophylaxis for dental procedures at risk?
- Amox/ampicillin
- Allergic: clindamycin
