36. Infective Endocarditis and Rheumatic Heart Disease Flashcards
What is infective endocarditis?
- infection of the inner layer of the heart (endocardium)
What structures does infective endocarditis affect? (4)
- heart valves (native or prosthetic)
- interventricular septum (septal defects)
- chordae tendinae
- intra-cardiac devices
What is the prognosis for infective endocarditis like?
- Getting worse (mortality rate is 30%=high)
- poor prognosis generally
- could be due to increased use of antibiotics, increased IV drug abuse and more patients undergoing cardiac surgeries
Is infective endocarditis a uniform procedure? Why? (5)
- Not uniform procedure
- Depends on which presentation, underlying cardiac disease, microorganism involved, presence/absence of complications, underlying patient characteristics
Which health professionals are often involved in the care for infective endocarditis patients? (6)
- primary care physicians/ acute medicine
- cardiologists
- surgeons
- microbiologists
- infectious disease team
- neurologists, radiologists, pathologists etc
What is the general prevalence of infective endocarditis?
- 3-10/100,000 in general population
- more common among elderly
- more common in males
- females worse prognosis
- ~25% don’t have underlying structural heart disease
What was infective endocarditis seen as previously? (4)
- presented in young adults
- well defined valve disease
- mostly rheumatic valve disease
- more chronic/subacute course
Why has changed in epidemiology of infective endocarditis? (4)
- earlier diagnosis
- more acute presentation
- changes in micro profile
- prophylaxis (conflicting recommendations)
What patients are more at risk of infective endocarditis NOW? (7)
- older patients (with degenerative aortic stenosis)
- prosthetic valve patients
- mitral valve prolapse patients
- bicuspid aortic valve patients
- congenital heart disease
- IV drug abusers
- immunocompromised patients
What is happening nowadays to rheumatic heart disease cases?
They are decreasing (<20%), infective endocarditis is due to other causes nowadays
What is rheumatic heart disease?
- chronic heart condition caused by rheumatic fever (it’s a complication of rheumatic fever)
- inflammation causes heart valves to inflame and stiffen as they are damaged
- affects blood flow through the heart
What might affect the change in how infective endocarditis is seen nowadays and how it presents? (4)
- health care associated
- invasive procedures on the rise
- intra cardiac devices
- no previously known valve disease
(or possibly increased use of antibiotics or IV drug use)
What are biggest cardiac risk factors for infective endocarditis? (8)
- rheumatic heart disease
- prosthetic heart valve
- surgery for prosthetic
infective endocarditis - prior native or surgery for infective endocarditis
- aortic stenosis
- ventricularseptal defect
- mitral valve prolapse (with mitral regurgitation)
- mitral valve prolapse (with no murmur)
What are specific predisposing valvular lesions for infective endocarditis? (5)
- mitral regurgitation
- aortic regurgitation
- aortic stenosis
- congenital heart disease
- prosthetic valve
What are common congenital heart disease which predispose patient to infective endocarditis? (6)
- cyanotic heart disease
- tetralogy of Fallot
- ventricular septal defects
- patent ductus arteriosus
- Eisenmenger syndrome
- ASD (atrial septal defect), coarctation of the aorta
What are non-cardiac risk factors for infective endocarditis? (13)
- IV drug use
- indwelling medical devices
- diabetes mellitus
- AIDS
- chronic skin infections, burns
- genitourinary infections or manipulation, including pregnancy, abortion, delivery
- alcohol cirrhosis
- gastrointestinal lesions
- solid organ transplant
- homeless, body lice
- pneumonia or meningitis
- contact with contaminated milk or farm animals
- dog/cat exposure
What is the pathophysiology behind infective endocarditis?
- endothelial damage occurs to endothelium
- damage can result due to turbulence (pulmonary stenosis, bicuspid aortic valve or mitral valve prolapse) or due to high pressure interfaces (e.g. VSD or PDA or coarctation of aorta)
- formation of fibrin-platelet aggregation/ growth
- invasion of nonbacterial thrombotic endocarditis occurs which then leads to bacteria becoming entrapped
What factors can cause mechanical disruption of valve endothelium?
- turbulent blood flow/ Venturi Effect
- high pressure interfaces
- electrodes
- catheters
- inflammation (rheumatic carditis or degenerative changes)
- infection by most types of organisms
What is the most common pathophysiological feature of infective endocarditis in terms of epithelium?
- local inflammation seen in most
- physically normal endothelium only in ~25% cases
What factors lead to bacteraemia which can eventually lead to infective endocarditis?
- extra-cardiac infections
- invasive procedures (oral, abdominal, genitourinary surgery or intravascular catheters)
- gingival disease (gum disease)
- daily activities (brushing teeth, bowel movements)
What are 3 main classifications of infective endocarditis?
- acute
- subacute
- chronic
What are different types of infective endocarditis localisation which affects its classification? (4)
- left sided native valve
- left sides prosthetic valve
- right sided
- device related (PPM, ICD)
What are different modes of acquisition of infective endocarditis?
- health care related (nonsocomial/hosp.acquired >48hrs after hospitalisation or non-nosocomial with signs and symptoms <48 hours after admission)
- community acquired
- IV drug abuse
What are the general symptoms of infective endocarditis? (6)
Variable presentation:
- bacteraemic episode
- fever (non-specific)
- fatigue (non-specific)
- malaise (non-specific)
- anorexia and weight loss
- sweats
- rigors
What are general signs of infective endocarditis? (6)
- congestive heart failure
- vascular/ immunological phenomena: immune complex deposition
- embolic phenomena: thromboembolism
- clubbing
- heart murmur
- splenomegaly
What signs does immune complex deposition lead to? (6)
- splinter haemorrhages
- vasculitic rash
- Roth Spots
- Osler’s nodes
- Janeway lesions
- nephritis
What signs does thromboembolism like symptoms lead to in infective endocarditis? (3)
- focal neurological signs
- peripheral embolus (30%) or abscess (renal, cerebral, splanchnic and vertebral)
- pulmonary embolus or abscess (right sided infective endocarditis)
What are features of a vasculitic rash? (4)
- diffuse
- non-blanching
- petechial (small, 1-2mm)
- purpuric
What are features of roth spots? (3)
- retinal haemorrhages
- white/pale centre
- coagulated fibrosis
What are features of Osler’s nodes? (5)
- deep, red spots
- painful
- raised
- finger pulps
- palms and soles affected
What are features of Janeway lesions? (6)
- flat and muscular
- echymotic (escape of blood into tissues from ruptured blood vessels)
- palms and soles affected
- non-tender
- pathognomonic (characteristic)
What features ADDITIONALLY to the fever make the fever a suspicion for possible infective endocarditis? (8)
- new murmur
- pyrexia of unknown origin
- known infective endocarditis causative origin
- prosthetic material ( PPM, ICD;implantable cardioverter defibrillator, prosthetic valve, baffle/conduit)
- previous infective endocarditis
- congenital heart disease
- new conduction disorder
- immunocompromised/ IV drug user
In which patients might signs of infective endocarditis be absent? (4)
- elderly
- after antibiotic treatment
- immunocompromised
- infective endocarditis involving less virulent/ atypical organisms
What investigation should be done to diagnose infective endocarditis? (6)
- marker of infection/inflammation (FBC, CPR, ESR, U+Es,)
- Urinalysis (+ve blood)
- blood cultures
- ECG (conduction delay)
- chest x ray (heart failure, pulmonary abscess)
- echocardiogram
What markers of infection/inflammation should be looked for in infective endocarditis? (4)
- full blood count ( looking for neutrophilia)
- CRP; C reactive protein (present in inflammation)
- ESR; erythrocyte sedimentation rate (present in inflammation)
- U+Es (urea and electrolytes); checks for nephritis, infection, sepsis
What blood cultures should be taken PRIOR to starting antibiotics?
- 3 sets
- from different sites
- > =6 hours between
What blood cultures should be taken during severe SEPSIS/ septic shock?
- 2 sets
- from different sites
- within 1 hour
What is checked for in urinalysis to diagnose infective endocarditis? (2)
- microscopic haematuria (red cell casts in urine)
- proteinuria
(present in at least 50% patients)
What is seen on ECG ininfective endocarditis?
conduction delay
What is seen on a chest x ray in infective endocarditis?(2)
- heart failure
2. pulmonary abscesses
What two types of echo need to be done for infective endocarditis? (2)
- transthoracic (TTE)
2. transoesophageal (TOE)
What echo is the FIRST line imaging that should be used?
TTE first (transthoracic)
What to do if TTE echo is normal?
-low clinical suspicion and therefore TOE not needed
What to do if TTE echo is abnormal if there is a positive test/suspicion?
TOE needed: - complication - abscesses - measure size of vegetation (all investigated)
What to do if TTE and TOE are normal but suspicion of infective endocarditis remains high?
repeat TTE and TOE at 7-10 days
What are new complications which can arise in repeat TTE and TOE related to infective endocarditis? (6)
- new murmur
- persisting fever
- embolism
- heart failure
- abscess
- atrioventricular block
What needs to be assessed if repeat TTE and TOE is done and uncomplicated infective endocarditis is suspected? (2)
- Asses ongoing treatment (e.g. silent complications or vegetation size)
- Asses treatment success on completion (e.g.valve morphology and cardiac function)
When doing a TTE at first, what are 4 possible outcomes and what is the next step?
- prosthetic valve or intracardiac device (so TOE next)
- poor quality TTE (so TOE next)
- Positive ( so TOE next)
- Negative (clinical suspicion of infective endocarditis assessed)
Once TTE is negative, what to do if clinical suspicion of infective endocarditis is
- high?
- low?
- if high then perform TOE (within 7-10 days)
- if low then stop investigations
What are possible microbiology blood cultures which can arise in infective endocarditis patients? (4)
- IE with +ve blood cultures
- IE with -ve blood cultures ;prior to antibiotic prescription
- IE with -ve blood cultures ;with fastidious organisms (ie require specific nutrients)
- IE with -ve blood cultures; intracellular bacteria