Endocarditis Flashcards
What is endocarditis?
Infection of the inside of the heart
What part of the heart is most often infected during endocarditis?
Almost always the valves.
Mostly left sided
What is the prognosis of endocarditis usually?
Fatal if it is untreated:
In acute infections death takes less than 6 weeks)
In subacute infections death occurs between 6 weeks and 3 months
in chronic endocarditis death occurs more than 3 months after initial infection
How common is endocarditis?
15 / 100000
300 - 400 cases per year in Perth
What are the 2 things that typically cause endocarditis?
Valvular endothelium damage due to trauma, turbulence, or metabolic changes results in platelet-fibrin deposition on valves.
Mucous membranes or other tissues get colonized and local ecologic factors, bacteriocins, IgA protease, or bacterial adherence results in trauma, bacteremia, and damage to valve
What disease historically caused endocarditis?
Rheumatic fever
What are the risk factors for endocarditis?
Age (>60)
Dental disease
IVDU
Haemodyalysis
Structural heart disease/valvular heart disease
Past IE
What bacteria are very good at attaching to heart valves?
Staph aureus
What heart diseases are associated with endocarditis?
Rheumatic heart disease
Prosthetic heart valves
Congenital heart disease
What bacteria are commonly associated with endocarditis?
Gram positive bacteria such as staph aureus, coag neg staph, and Viridans group strep
How is infective endocarditis often treated?
With antibiotics
Who get S.Aureus endocarditis most often?
Drug abusers
What are the most common bacteria to cause prosethetic valve endocarditis?
First 12 months after surgery bacteria most common to infect prosthetic valves change. Initially during the first 3 months S.aureus and coag negative staph most commonly causes infection but by the 12th month strep and staph cause it equally and then after 12 months the strep take over as most common causes of prosthetic valve endocarditis
What are complications of endocarditis?
Valve destruction causing heart failure
Intra-cardiac abscess and conduction disturbance (heart block)
Embolic MI
Metastatic abscesses (not uncommon 10 - 30%)
Mycotic aneurysms (often asymptomatic but can also rupture)
Immunological complications
Sepsis in acute IE
How common is embolic cardiac failure?
Clinically apparent in 10 - 40%
What problems can embolic complications of endocarditis result in?
Stroke/Limb/Viscera
Where can metastatic abscesses form?
Viscera
Spine
Joints
What are the immunological complications that can take place in infective endocarditis?
Seen more commonly in sub acute cases
Glomerulonephritis most significant
Immune complex deposition can trigger inflammation in surrounding areas
What are the ways of diagnosing endocarditis?
Blood cultures to check for infection.
ECG (show that theres a vegetation and valve disruption)
How are blood cultures carried out to diagnose infective endocarditis?
Initial 3 sets from 3 sites
3rd is 1 hour after the 1st
Occasionally serology and blood PCR for culture negative cases are used
What can imaging show endocarditis?
It can reveal metastatic foci (guided by clinical picture)
What are the Duke major criteria for endocarditis?
Sustained bacteremia or vegetations on the valve
What are the Duke minor criteria for endocarditis?
The other symptoms that are associated with endocarditis
How is endocarditis treated?
Antibiotics: Most IE are treated with 6 weeks of intravenous antibiotics (4 weeks for highly penicillin sensitive streptococci).
Often we wait until they are stable if they are unstable we use empirical regimens are used unless pathogen specific treatment is available.
For streptococci and enterococci they don’t just look at antibiotic sensitive or resistant they also look at Mean Inhibition Concentration to know whether to use penicillin alone or penicillin and gentamicin. [must remember for exam!]
Valve surgery if necessary (vegetectomy/repair)
How effective are antibiotics for treatment of IE?
95% of cases there’s a 4% relapse or reinfection of the same bug
How is prosthetic valve IE treated if it’s caused by Staph?
Rifampicin (Biofilm effect) + Gentamicin in Staph (in addition to flucloxacillin (MSAA) or vancomycin (MRSA)
How is prosethetic valve IE treated if its strep?
Rifampicin + Gentamicin
When must valve surgery be done?
Indications are:
Heart Failure
Cardiac abscess +/- heart block
Large vegetation for left sided IE >1cm
Ongoing embolisation despite antibiotic therapy
Persistent bacteraemiaa despite 7 days antibiotic therapy
Fungal IE (particularly fungal Prosthetic Valve Endocarditis)
IE recurrence rate with modern therapy is low
Is giving prophylactic antibiotics prior to dental procedures shown to be a good idea?
There’s no good clinical evidence that prophylactic antibiotics in dental procedures should be given
Who should be given prophylactic antibiotics?
Dental procedures in people with:
People with prosthetic cardiac valve/cardiac repair
Previous IE
Congenital heart disease (uncorrected cyanotic defect or corrected with prosthetic material)
Rheumatic heart disease in high risk patients
Cardiac transplants with valvulopathy
What should people that are given prophylactic antibiotics be given?
Amoxicillin 2g OD or cephalexin PO or clindamycin 600mg PO in the penicillin allergic
