Infective Endocarditis Flashcards
what is the definition of endocarditis?
infection involvong the endocardal layer
which sites of the endocardium can be infected in IE?
valvular structures (natuve or prosthetic) chordae tendinae septal defects mural endocardium
what is the mortality for IE?
15-30%
is IE more common in males or females?
males
does IE have a worse prognosis in males or females?
Females
what are the health professionals involved in the care of IE patients?
Frontline /referring Doctors-Acute physicians/GPs
Cardiologist-Diagnostics
Microbiologist/Infectious disease team
Cardiothoracic surgeon
Radiologist
Neurologist /Neurosurgeons (for embolic events)
Reference centre(complicated Infective endocarditis)
which groups of patient is IE seen in presently?
- 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
what are the 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
which mitral valve disease increases the risk of IE?
mitral valve prolapse
which congenital heart diseases increase the risk of IE?
Ventricular septal defect
Bicuspid aortic valve
Patent ductus arteriosus
describe the pathophysiology of IE from endothelial disruption?
Normal valve endothelium is resistant to colonization and infection.
Mechanical endothelial disruption exposures extracellular matrix protein → production of tissue factors.
Deposition of fibrin and platelets→ Non-bacterial thrombotic endocarditis (NBTE).
NBTE facilitates bacterial adherence and infection.
what can cause damage to the endothelium of heart valves causing possibly causing IE?
Turbulent blood flow (Venturi effect-low pressure) Electrodes Catheters Inflammation (rheumatic carditis) Degenerative valve disease
describe the pathophysiology of IE from inflammation?
Endothelial inflammation without valve lesion may promote IE.
- Inflammation of endothelial cell → expression of integrins (β1 family)
- Integrins are transmembrane protein-binds circulating fibronectin to endothelial surface.
- Staph aureus (other IE pathogens) carry fibronectin → binding proteins on their surface.
- Adherent organisms trigger active internalization into valve endothelial cells.
which invasive procedures can cause bacteraemia leading to IE?
- Dental procedures requiring manipulation( gingival /periapical region
- Dental procedures -perforation of oral mucosa
- GU and GI surgery
- Intravascular catheters
which non-invasive activities can cause bacteraemia leading to IE?
(chewing and tooth brushing)-low grade bacteraemia of short duration but with high incidence.
what general things can cause bacteraemia leading to IE?
- invasive procedures (eg. dental procedures)
- extra-cardiac infections
- non-invasive activities
what are the main causative organisms of IE?
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)
how can IE be classiified?
- 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)
how can IE be classified according to localization?
- left-sided native valve IE
- left-sided prosthetic valve IE (PVE) (early <1 year after surgey, late >1 year after surgery)
- right-sided IE
- device related IE (permanent pacemaker or cardioverter-defibrillator)
how can IE be classified according to mode of acquisition?
- Health-care associated IE: nosocomial (signs/symptoms after 48hrs in hospital) and non nosocomial (signs/ symptoms less than 48hrs in hospital and residient in nursing home, long-term care facility, hospitalised <90 days earlier, home nursing or IV therapy, haemodialysis or IV chemotherapy)
- Community-acquired IE- signs in hospital < 48hrs after admission and not fulfillig criteria above
- IVDA IE
what is active IE?
-IE with persistant fever and positive blood cultures
-active inflammatory morphology found at surgery
-patient stillunder antibiotic therpy
histopathological evidence of active IE
what are the classifications of recurrent IE?
relapse- same infection microorganism < 6months aftere initial episode
reinfection- infection with different microorgansim or same microorganims but >6monthd after initial infection
is the presentation of IE consistent or varied?
varied
which patients have an atypical presentation in IE?
elderly
immunocompromised
what are the signs of acute IE?
- fever
- embolic signs/symtpoms
- decompensated (functional deterioration when healthy before) HF
what are the signs of subacute IE?
- fever
- non-specific constitutional symptoms or palpitation
- immunologic/vascular phenomena.
what are the common symptoms of IE?
Fever/chills Night sweats, malaise, fatigue, anorexia, weight loss Weakness Arthralgia Headache Shortness of breath
what are constitutional symptoms?
a group of symptoms that can affect many different systems of the body.
what are rhe clinical signs of IE?
Cardiac murmur (regurgitant murmur) with signs of heart failure Janeway lesions Osler nodes Roth spot Meningeal signs Splinter haemorrhage Cutaneous infarcts Vasculitic rash
which signs of IE are from immune complex deposition?
Osler nodes
Roth spots
what are Janeway lesions ?
Haemorrhagic ,macular, painless plaques with predilection for palms and soles.
what are Osler nodes?
Small ,painful nodular lesion found on pads of fingers or toes
what will lead you to suspect IE?
- new regurgitant murmur
- embolic events of unknown origin
- sepsis of unknown origin (esp. if IE causative organism)
- fever with:
- intracrdiac material
- previous history of IE
- other predisposition to IE (immunocompromised, IVDA)
- predisposition and recent intervantion with associated bacteraemia
- evidence of congestive heart failure
- new conduction disturbance
- positive blood cultures with typical IE causative organisms or positive serology for hronic Q fever
- vascular or immunological phenomena: embolic event, Roth spots, splinterhaemorrhages, Janewya lesions, Osler’s nodes
- foval or non-specific neurological symptoms or signs
- evidence of pulmonary embolism/infiltration (right sided IE)
- peripheral abscesses (renal, splenic, cerebral, vertebral) of unknown cause
what are the investigations for 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,MRI,18F-FDG -PET/CT and Leucocyte SPECT/CT –detect silent vascular phenomena/ endocardial lesions
-Echocardiography ( transthoracic (TTE) ± transesophageal (TOE)
why are FBC and CRP blood tests carried out for in IE?
elevated acute inflammatory markers
why are U+Es carried for IE?
to look for renal failure caused by embolic events
why is an ecg carried out in IE?
to look for prolongation of PR interval
why is CXR carried out for IE?
look for pulmonary abscess or congestion
what are the 2 major ESC 2015 Modified Duke’s criteria for IE?
- Blood cultures positive for IE
- imaging positive for IE
for blood cultures to be positive for IE what must the result be?
- Typical microorganisms consistent with IE from 2 separate blood cultures:
- Microorganisms consistent with IE from persistently positive blood cultures:
- Single positive blood culture for Coxiella burnetii or phase I IgG antibody titre >1:800
what are are the imaging results that can be used for a positive diagnosis of IE?
- Echocardiogram positive for IE:• Vegetation
• Abscess, pseudoaneurysm, intracardiac stula
•Valvular perforation or aneurysm
• New partial dehiscence of prosthetic valve - . 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.
- Definite paravalvular lesions by cardiac CT.
what are the minor criteria in ESC 2015 Modified Duke’s Criteria?
- Predisposition such as predisposing heart condition, or injection drug use.
- Fever defined as temperature >38°C.
- Vascular phenomena (including those detected only by imaging): major arterial emboli, septic pulmonary infarcts, infectious (mycotic) aneurysm, intracranial haemorrhage, conjunctival haemorrhages, and Janeway’s lesions.
- Immunological phenomena: glomerulonephritis, Osler’s nodes, Roth’s spots, and rheumatoid factor.
- Microbiological evidence: positive blood culture but does not meet a major criterion as noted above or serological evidence of active infection with organism consistent with IE.
what is the combinations of major and minor criteria for definite IE diagnosis?
2 major
1 major + 3 minor
5 minor
what is the combinations of major and minor criteria for possible IE diagnosis?
1 major + 1 minor
3 minor
what must be considered before treatment of IE is given?
- 3 sets of blood culture
- whether patient has had previous antibiotic therapy
- native or prosthetic valve
- place of infection (community etc) and local epidemiology for antibiotic resistance and specific genuine culture negative pathogens
what are the 3 antibiotics given in community-acquired native valve or late (>12 months post surgery) prosthetic valve endocarditis (not penicillin allergic)?
ampicillin with flucloxacillin, cloxacillin or oxacillin with gentamicin
what are the 2 antibiotics given in community-acquired native valve or late (>12 months post surgery) prosthetic valve endocarditis ( penicillin allergic)?
vancomycin
with
gentamicin
what are the 3 antibiotics given in for ealry PVE or nosocomial and non-nosocomial healthcare associated endocarditis?
vancomycin with gentamicin with rifampin (3-5 days later)
what are the patient characteristic which can be used to predict a poor outcome in IE?
older age
prosthetic valve IE
dibetes mellitus
comorbidity
what are the clinical complications of IE which can be used to predict a poor outcome?
heart failure renal failure more than a moderate area of ischaemia stroke brain haemorrhage septic shock
which microorgansims cause a poor outcome in IE?
staph aureus
fungi
non-HACEK gram negative bacilli
what are the echo findings which can predict a porr outcome of IE?
periannular complications severe left-sided valve regurgitation low left ventricular ejection fraction pulmonary hypertension large vegetations severe prosthetic valve dysfunction premature mitral valve closure and other signs of elevated diastolic pressures
what are the complications and indications for srugery in IE?
heart failure- (valvular regurg.)
uncontrolled infection (perivavular abscess)
prevention of systemic embolisation (migration of cardiac vegetation to brain/spleen from left IE
which patients are given prophylaxis for IE?
- patients with any prosthetic valve
- patients with a previous episode of IE
- patients with CHD:
a) cyanotic CHD
b) any type of CHD repaired with prosthetic material up to 6 months after procedure. (lifelong if residula vegetations of shunt)
what are the preventative measures for IE?
- Strict dental and cutaneous hygiene. Dental follow-up twice a year.
- Disinfection of wounds.
- Eradication or decrease of chronic bacterial carriage :skin, urine etc
- Curative antibiotics for any focus of infection.
- No self-medication with antibiotics.
- Strict infection control measures for any at-risk procedures.
- Discourage piercing and tattooing.
- Limit the use of infusion catheters and invasive procedures when possible.
