Infective endocarditis Flashcards
Definition of Infective endocarditis (IE)
Endocarditis - infection involving the endocardial surface
Valvular structures- native and prosthetic valves
Chordae tendineae
Sites of septal defects
Mural endocardium – the posterior wall of the left atrium becomes rough and wrinkled
IE is a deadly disease associated with high mortality (15-30% in-hospital) and severe complication.
Mortality and prognosis remains unchanged for over 30 years
Despite advancement in management /diagnostics
Infective endocarditis incidence
IE is a rare disease with low incidence
Incidence :3-10 cases /100,000 people per year
14.5 episodes /100,000 people are 70-80yrs old
Male : Female ratio ≥2.1
Worse prognosis in female
IE incidence in the past
Young adults with previously well-identified valve disease
Chronic /subacute course (delayed diagnosis)
IE incidence now
Older patients with degenerative heart disease ( Aortic Stenosis)
Healthcare –associated procedures
Intra cardiac devices (ICD)
Valve disease( Mitral valve prolapse, Bicuspid aortic valve)/Congenital heart disease
Prosthetic valve
IVDU
Immunocompromised patients
Risk factors for native valve IE
Mitral valve disease Rheumatic heart disease Congenital heart disease Degenerative heart disease Asymmetrical septal hypertrophy Intravenous Drug abusers Alcoholic cirrhosis Diabetic mellitus Indwelling medical devices
Mitral valve prolapse
high prevalence 2-4%
20% are young female
relative risk of 3.5-8.2 for endocarditis
Congenital heart disease and endocarditis
10-20% of endocarditis cases in young adults
8% of cases of endocarditis in older adults
can be ventricular septal defect, bicuspid aortic valve, patent ductus arterious
Pathophysiology of how endocarditis starts
normal valve endocardium is resistant to colonisation and infection.
then mechanical endothelial disruption exposes ECM protein which promotes production of tissue factors.
this causes deposition of fibrin and platelets and causes non bacterial thrombotic endocarditis (NBTE)
NBTE facilitates bacterial adherence and infection
Pathophysiology for damaged endothelial valve
turbulent blood flow (Venturi effect) Electrodes catheters inflammation (rheumatic carditis) degenerative valve disease
Pathophysiology for normal valve endothelial Inflammation
Endothelial inflammation
expression of integrins from these cells (transmembrane proteins that bind circulating fibronectin to the endothelial surface.
staph. aureus and other pathogens carry fibronectin and so bind proteins on their surface
adherent organisms trigger active internalization into valve endothelial cells
Pathophysiology: Bacteraemia
Invasive procedure
Dental procedures requiring manipulation( gingival /periapical region
Dental procedures -perforation of oral mucosa
GU and GI surgery
Intravascular catheters
Extra-cardiac infections
Non-invasive activities (chewing and tooth brushing)-low grade bacteraemia of short duration but with high incidence.
Aetiology- causative organisms
Viridans group streptococci Staphylococcus aureus Enterococci Coagulase-negative staphylococci Haemophils parainfluenzae Actinobacillus Streptococcus bovis Fungi Coxiella burnetii, Brucella species, Culture-negative Haemphilus species, Actinobacillus,actinomycetemcomitans, Cardiobacterium hominis, eikenella corrodens and Kingella species (HACEK)
Classification of Infective Endocarditis
Acute(days/weeks) or subacute(weeks to months)
Nidus(localization) of infection± intra-cardaic material
Mode of acquisition (IVDU, Healthcare or community)
Active Infective endocarditis
Recurrence (relapse or reinfection)
Diagnosis of Infective Endocarditis
Bacteraemia with audible murmur should raise suspicion
could be in elderly or immunocompromised patients
acutely- fever, embolic signs, decompensated HF
subacute- fever, nonspecific constitutional symptoms or palpitation and immunologic/vascular phenomena
Common symptoms
fever/chills night sweats, malaise, fatigue, anorexia, weight loss weakness arthralgia (joint pain) headache SOB
Clinical signs of IE
regurgitant murmur with signs of HF janeway lesions (Haemorrhagic ,macular, painless plaques with predilection for palms and soles.)
Osler nodes (Small ,painful nodular lesion found on pads of fingers or toes)
Roth spots (Retinal haemorrhage with a white or pale centre)
meningeal signs
splinter haemorrhage
cutaneous infarcts
Petechial haemorrhage (on back of mouth)
vasculitic rash
Investigation of IE
Blood culture- Timing. 3 sets and sites 30mins apart. +/- cultures
FBC.ESR/CRP- elevated acute inflammatory makers
U+Es- renal failure
Urinalysis- +ve for blood
ECG: PR interval prolongation ≥200ms
CXR: Pulmonary congestion or abscess.
Further Imaging for subgroups – MSCT(multislice coronary angiogram, shows perivalvular abscesses better than ECHO),MRI,18F-FDG -PET/CT and Leucocyte SPECT/CT –detect silent vascular phenomena/ endocardial lesions
Echocardiography ( transthoracic (TTE) ± transesophageal (TOE)
ESC 2015 Modified Duke’s Criteria-Major criteria
- Blood cultures positive for IE
Typical microorganisms consistent with IE from 2 separate blood cultures:
Viridans streptococci, Streptococcus gallolyticus (Streptococcus bovis), HACEK group,
Staphylococcus aureus; OR
Community-acquired enterococci, in the absence of a primary focus;
OR
Microorganisms consistent with IE from persistently positive blood cultures:
≥2 positive blood cultures of blood samples drawn >12 h apart; OR
All of 3 or a majority of ≥4 separate cultures of blood (with first and last samples drawn ≥1 h apart);
OR
C. Single positive blood culture for Coxiella burnetii or phase I IgG antibody titre >1:800
- Imaging positive for IE
A. Echocardiogram positive for IE:
• Vegetation
• Abscess, pseudoaneurysm, intracardiac fistula
•Valvular perforation or aneurysm
• New partial dehiscence of prosthetic valve
B. Abnormal activity around the site of prosthetic valve implantation detected by 18F-FDG PET/CT (only if the prosthesis was implanted for >3 months) or radiolabelled leukocytes SPECT/CT.
C. Definite paravalvular lesions by cardiac CT.
ESC 2015 Modified Duke’s Criteria-Minor criteria
Predisposition such as heart condition or injection drug use
fever over 38C
vascular phenomena such as major arterial emboli, septic pulmonary infarcts, infectious aneurysm, intracranial haemorrhage, conjunctival haemorrhages, janeways lesions
immunological phenomena such as glomerulonephritis, oslers nodes, roths spots, rheumatoid fever
microbiological evidence such as positive blood culture but doesn’t meet a major criteria or serological evidence of active infection with organism consistent with IE
Modified Duke Criteria
Diagnosis of Definite IE : 2 major criteria
or 1 1 major criterion + 3 minor criteria or 5 minor criteria
Diagnosis of Possible IE : 1 major criterion + 1 minor criterion OR
3 minor criteria
IE Rejection criteria : Resolution of endocarditis syndrome with antibiotics therapy for ≤ 4 days
Empirical treatment of IE
3 sets of blood culture 30mins apart THEN IV antibiotics (amoxicillin+flucoxacillin+gentamicin or gentamicin+vancomycin if allergic)
consider previous surgery and antibiotics and place of infection for local epidemiology
Predictors of poor outcome
old age prosthetic valve IE diabetes mellitus comorbidity HF RF IS brain haemorrhage septic shock staph. aureus fungi non HACEK gram negative bacilli periannular complications severe left sided valve regurgitation low left ventricular ejection fraction PHT large vegetations severe prosthetic valve dysfunction premature mitral valve closure
Complications and indications for surgery
Heart failure in IE: valvular regurgitation- leaflet perforation etc
42-60% of Native Valve Endocarditis(NVE)
Aortic IE> Mitral IE
Uncontrolled Infection: Perivalvular abscess
More common in Aortic IE (10-40%) in NVE
56-100% of Prosthetic valve endocarditis(PVE) Mortality rate 41%
Prevention of systemic embolism: migration of cardiac vegetation to brain/spleen from left-IE Size and mobility of vegetation .
Pulmonary embolism are the results of right sided IE.
Principles of prevention of IE
1.The principles of antibiotic prophylaxis when performing procedures at risk of IE in patients with predisposing cardiac conditions is maintained.
2. Antibiotic prophylaxis must be limited to patients with the highest risk of IE undergoing the highest risk dental procedures. (dental procedures requiring manipulation of the gingival or periapical region of the teeth or perforation of the oral mucosa)
Patients with a prosthetic valve, including transcatheter valve, or a prosthetic material used for
cardiac valve repair.
Patients with previous IE.
Patients with congenital heart disease:
- any cyanotic congenital heart disease. - congenital heart disease repaired with prosthetic material whether placed surgically or by
percutaneous techniques, up to 6 months after the procedure or lifelong if there remains residual shunt or valvular regurgitation.
3. Good oral hygiene and regular dental review are more important than antibiotic prophylaxis to reduce the risk of IE.
4.Aseptic measures are mandatory during venous catheter manipulation and during any invasive procedures in order to reduce the rate of health care-associated IE.
basically use abx right, wash hands, disinfect wounds, good hygiene, no piercings or tattoos, limit infusion catheters etc
