Infective Endocarditis and Rheumatic Heart Disease Flashcards
What is infective endocarditis?
Infection of the endocardium (inner layer of the heart)
What structures might be infected by infective endocarditis?
Heart valves
Interventricular septum
Chordae tendinae
Intra-cardiac devices
What is the change in the incidence and mortality of infective endocarditis in the last 30 years?
No change in either
What is the general prognosis and mortality of infective endocarditis?
Poor prognosis
High mortality
What factors affect the prognosis and morality from infective endocarditis?
Underlying cardiac disease
Micro-organism involved
Presence of complications
Patient characteristics
What professions are involved in the collaborative approach to treating infective endocarditis?
Primary care physicians Acute medicine Cardiologists Surgeons Microbiologists Infectious disease Neurologist Neurosurgeon Radiologist Pathologist
What is the incidence of infective endocarditis?
3-10 episodes per 100,000 person years in general population
14.5 episodes per 100,000 person years in 70-80 year olds
What is the difference in incidence of infective endocarditis between males and females?
Males : females
2:1
Is the prognosis worse in males or females?
Females
What percentage of people infected with infective endocarditis will not have an underlying structural heart disease?
Around 25%
What are the potential epidemiologies of infective endocarditis?
Older patients with degenerative AS Rheumatic heart disease Health care associated Invasive procedures Intra-cardiac devices Prosthetic valves Mitral valve prolapse Bicuspid aortic valve Congenital heart disease IV drug abuse Immunocompromise
What are the potential pathophysiologies of infective endocarditis?
Adherence and invasion of non-bacterial thrombotic endocarditis
Mechanical disruption of valve endothelium
What are the possible causes of mechanical disruption of the valve endothelium?
Turbulent blood flow Electrodes Catheters Inflammation Degenerative changes
What percentage of people with infective endocarditis will have a physically normal endothelium?
25%
When might bacteraemia be present in infective endocarditis?
Extra-cardiac infections
Invasive procedures e.g. oral, abdominal, genitourinary, intravascular catheters
Gingival disease
How is infective endocarditis classified?
Acute, subacute or chronic
Early (< 1 year after surgery) or late (> 1 year after surgery)
Side of infection
Infected devices
What is right sided infective endocarditis associated with?
IV drug abusers
What are the presenting features of nosocomial/idiopathic infective endocarditis?
Signs and symptoms > 48 hours after hospitalisation
What are the presenting features of non-nosocomial infective endocarditis?
Signs and symptoms < 48 hours after hospitalisation plus healthcare contact
What factors might be associated with infective endocarditis?
Home-based nursing, IV therapy or haemodialysis < 30 days before onset
Acute care facility < 90 days before onset
Resident in nursing home or long-term care facility
IVDA
What features might suggest infective endocarditis?
Variable presentation
High index of suspicion
Bacteraemic episode
Non-specific symptoms e.g. fever, fatigue, malaise
What are the possible signs of infective endocarditis?
Congestive cardiac failure Vascular or immunological phenomena Immune complex deposition Embolic phenomena Focal neurological signs Peripheral embolus or abscess (30%) Pulmonary embolus or abscess
What are the signs of immune complex deposition?
Vasculitic rash - diffuse, non-blanching, petechial, purpuric
Roth spots - retinal haemorrhages, white/pale centre, coagulated fibrosis
Osler’s nodes - deep red spots, painful, raised, on finger plumps, palms and soles
Janeway lesions - flat, macular, echymotic, on palms and soles, non-tender
Nephritis
What should prompt a high index of suspicion?
Fever New murmur Pyrexia of unknown origin when other diagnoses have been ruled out Known IE causative organism isolated in culture Prosthetic material Previous IE Congenital heart disease New conduction disorder Immunocompromised IVDA
When might signs of infective endocarditis be absent?
Elderly
After antibiotic treatment
Immunocompromised
IE involving less virulent or atypical organism
What should be done in the investigation of suspected infective endocarditis?
Markers of infection/inflammation FBC CRP ESR U&Es Blood culture prior to starting antibiotics Urinalysis ECG CXR Echocardiogram
What blood cultures should be taken in the investigation of infective endocarditis?
3 sets from different sites with > 6 hours in between
In severe sepsis or septic shock then take 2 sets of bloods from different sites within 1 hour
What is the standard echocardiography protocol in infective endocarditis?
Transthoracic 1st line imaging
If good quality TTE normal with low clinical suspicion then no TOE needed
If TTE normal with high clinical suspicion then TOE Needed
If TTE or TOE is normal but suspicion of IE remains high, repeat at 7-10 days
If TTE positive then do TOE for complications, abscesses and measuring size of vegetation
When should TTE and TOE be repeated?
New complication New murmur Persisting fever Embolism Heart failure Abscess Atrioventricular block
In uncomplicated IE, when is an echo repeated?
To assess ongoing treatment for ‘silent’ complications and vegetation size
To assess treatment success on completion - view valve morphology and cardiac function
Why might a patient with IE have negative blood cultures?
Prior antibiotic treatment
Fastidious organism
Intracellular bacteria
85% of all IE patients with positive blood cultures will have one of what three organisms?
Streptococci
Enterococci
Staphylococcus
What are the streptococci species which might be cultured in IE?
Milleri
Anginosus
ORAL; Sanguis Mitis Salivarius Mutans Germella Morbillorum
What are the nutritionally variant defective streptococci which have been reclassified and might be cultured in IE?
Abiotrophia
Granulicatella
What is group D streptococcus associated with?
GI tract
What are the enterococci species that might be cultured in IE?
Faecalis
Faecium
Durans
What are the staphylococcal species that might be cultured in IE?
Aureus
Coagulase negative
Epidermidis
If a blood culture in a patient with suspected IE comes back negative due to prior antibiotic treatment, what is the most likely causative organism?
Oral streptococcus or coagulase negative staphylococcus (CNS)
What fastidious organisms might cause IE?
Nutritionally variant streptococci
Fastidious gram negative bacilli - HACEK group
Brucella
Fungi
What percentage of IE is caused by intracellular bacteria?
5%
What intracellular bacteria might be responsible for IE?
Coxiella burnetii
Bartonella
Chlamydia
How can intracellular bacteria be identified?
Serological testing
Cell culture
Gene amplification
PCR
What are the major Duke Criteria?
Blood cultures positive for IE
- typical organisms consistent with IE from 2 separate blood cultures
- organisms consistent with IE from persistently positive blood cultures
- single positive blood culture for Coxiella burnetii
Evidence of endocardial involvement
- positive echocardiogram
- new valvular regurgitation/murmur
What are the minor Duke Criteria?
Predisposition
- predisposing heart condition
- injection drug use
Fever
Vascular phenomena
- major arterial emboli
- septic pulmonary infarcts
- mycotic aneurysm
- intracerebral haemorrhage
- conjunctival haemorrhage
- Janeway lesions
Immunological phenomena
- glomerulonephritis
- Osler’s nodes
- Roth spots
- rheumatoid factor
Microbiological evidence
- positive blood cultures that do not meet major criteria
- serological evidence of active infection with organism consistent with IE
How many Duke Criteria are needed to diagnose IE?
Definite:
- 2 major
- 1 major and 3 minor
- 5 minor
Possible:
- 1 major
- 3 minor
What are the treatment options for IE?
Antibiotics
Aminoglycosides
Surgery
Removal of prosthetic material
What does the choice of antibiotic for IE treatment depend on?
Prior received antibiotics Native or prosthetic valves Dates of any surgeries Knowledge of local epidemiology and antibiotic resistance Specific culture-negative pathogens
What organisms are responsible for native valve IE?
Staphylococci
Streptococci
HACEK species
Bartonella species
What antibiotic treatment is given for IE of native valves?
4 weeks of:
IV gentamicin 1mg 12 hourly and IV amoxicillin 2g 4 hourly
Substitute amoxicillin for vancomycin if penicillin allergic
When is IV vancomycin used to treat IE of native valves?
If penicillin allergic
Sepsis
MRSA
What antibiotic treatment is given for IE of prosthetic valves?
6 weeks of:
IV gentamicin and IV vancomycin
When is Rifampicin used to treat IE of prosthetic valves?
MSSA
MRSA
Non-HACEK G-negative pathogens
What are the disadvantages of gentamicin?
Nephrotoxic
Ototoxic
How is gentamicin dosed?
Dosing to actual body weight or ideal body weight if obese
What investigations are repeated throughout treatment?
Daily FBC, U&Es and CRP
ECG every 1-2 days
Echo weekly
What patients are usually affected by fungal IE?
PVE
IVDA
Immunocompromised
How is fungal IE treated?
Dual anti-fungals
Valve replacement
Anti-fungal therapy often maintained long-term, sometimes lifelong
What are the complications/indications for surgery in IE?
Heart failure Fistula formation Leaflet perforation Uncontrolled infection Enlarging vegetation Abscess formation Atrioventricular heart block Embolism Embolism and vegetation > 10 mm Isolated vegetation > 15mm Prosthetic valve dysfunction/dehiscence
Why might there be an uncontrolled infection?
Inadequate antibiotic treatment Resistant organisms Locally uncontrolled infection Infected lines Embolic complications Extra-cardiac site of infection Adverse reaction to antibiotics
What would indicate an uncontrolled infection?
Persistent fever and positive blood cultures after 7-10 days
What is the incidence of prosthetic valve endocarditis?
1-6% of valve prosthesis
Incidence of 0.3-1/2% per patient per year
10-30% of all cases of IE
What is prosthetic valve IE associated with?
Difficulties in diagnosis
Difficulties with optimal therapeutic strategy
Poor prognosis
Removal of prosthetic material
Medical therapy alone is associated with high mortality and risk of recurrence
What are the cardiac conditions at highest risk of IE?
Acquired valvular heart disease e.g. stenosis, regurgitation Valve replacement Structural congenital heart disease Hypertrophic cardiomyopathy Previous IE
What percentage of cases of IE are healthcare associated?
30%
What is the in-hospital mortality of IE?
9.6-26%