Infective endocarditis and rheumatic Heart disease Flashcards
(24 cards)
IE is an infection of either
Inner layer of heart (endocardium) Heart valves (native or prosthetic) Interventricular septum (septal defect) Chordae tendinae Intra-cardiac devices
Non-cardiac risk factors for IE
IV drug use Indwelling medical devices Diabetes Mellitus AIDs Chronic skin infections/burns Genitourinary infections or manipulation including pregnancy, abortion and delivery Alcoholic cirrhosis GI lesions Solid organ transplant Homeless, body lice Pneumonia, meningitis Contact with containerised milk or infected farm animals Dog/cat exposure
Cardiac risk factors for IE
MVP, no murmur MVP with MR VSD Aortic stenosis Rheumatic heart disease Prosthetic heart valve Cardiac surgery for native IE Prior native IE Surgery for prosthetic IE
Early steps in bacterial colonisation
Colonisation of damaged epithelium
Colonisation of inflamed valve tissues
Venturi effect
High pressure, low velocity to High velocity, low pressure to High pressure, low velocity
Cardiac conditions at highest risk of IE
Acquired valvular heart disease (stenosis, regurgitation) Valve replacement Structural congenital heart disease Hypertrophic cardiomyopathy Previous IE
Mode of acquisition of IE: health care related
- Nosocomial/idiopathic (symptoms/signs >48 hours after being admitted)
- Non-nosocomical (sings/symptoms <48 hours after admitted and health care contact)
- Home based nursing/IV therapy. Haemodialysis <30 days before onset
- Acute care facility <90 days before onset
- Resident in nursing home/long term care facility - Community acquired
- IVDA
Types of IE
Acute
Subacute
Chronic
Symptoms/signs of IE
Non-specific - Fever (VERY COMMON) - Fatigue - Malasie Recent Dental appointment Others - weight loss - Headache - muscoskeletal pain - Altered mentation - Murmur (VERY COMMON) - Peripheral stigmata petechiae - Janeway lesions - Oslers nodes - Splinter haemorrhages - Clubbing - Neurological manifestations - Roths spots - Splenomegaly or infarct - Congestive Heart failure - Vascular (immunological phenomena) - Embolic phenomena
Diagnostic signs of IE might be absent in
Elderly
After antibiotic treatment
Immunocompromised
IE involving less virulent/Atypical organisms
Markers of infection/inflammation
FBC (neutrophilia)
CRP (C-reactive protein: marker of inflammation)
ESR (erythrocyte sedimentation rate: marker of inflammation)
U+ Es (Urea and electrolytes) look for…
Nephritis
Infection
Sepsis
Investigations for IE
Inflammation/Infection markers (FBC, CRP, ESR) U + Es Blood cultures (prior to antibiotics) Urinalysis ECG ECHO CXR
Microbiology: IE with positive blood cultures involve… (85% of all IE)
Streptococci
Enterococci
Staphylococcus
Microbiology: IE with negative blood cultures may be due to…
Prior antibiotic treatment
Microbiology: IE with negative blood cultures may be due to fastidious organisms;
Nutritionally variant streptococci
Fastidious gram -ve bacilli - HACEK group
Brucella
Fungi
Microbiology: IE with negative blood cultures due to intracellular bacteria; (5% of all IE)
Coxiella burnetti
Bartonella
Chlamydia
Modified Duke Criteria for diagnosis of IE
MAJOR CRITERIA - Identifying organism (Blood cultures for positive IE) - Providing evidence of infection anywhere within the heart (Positive ECHO, New valvular regurgitation/murmur) MINOR CRITERIA - Focus on the endocarditis complex of clinical findings (predisposition, fever, vascular phenomena, immunological phenomena, microbiological evidence) SO DEFINITE: - 2 major OR - 1 major and 3 minor - 5 minor POSSIBLE: - 1 major - 3 minor
Treatment for IE
Antibiotics (IV, start as soon as blood cultures taken)
+/- surgery
Choice of antibiotics depend on
Have they received prior antibiotics? Native/prosthetic valves (early vs. late PVE) Knowledge of - local epidemiology - Local antibiotic resistance - Specific culture negative pathogens
Specific empirical treatment
NATIVE VALVES: 4 weeks - gentamycin + amoxicillin + vancomycin
NATIVE VALVES AND SEPSIS: gentamycin and vancomycin
PROSTHETIC VALVES: 6 weeks - Gentamycin + vancomycin + rifampicin
Specific antibody choice for the organism depends on
Microorganisms isolated
Sensitivities
Resistance
Treatment for IE due to fungi
Dual antifungals
Valve replacement
Other maintained long term and sometimes for life
Complications of IE: indications for surgery
Heart failure Fistula formation Leaflet perforation Uncontrolled infection Enlarging vegetation despite treatment Abscess formation Atrioventricular heart block Embolism Prosthetic valve dysfunction/dehiscence
