Post on 12-Apr-2015
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Cardiovascular InfectionsCardiovascular Infections
Dr. Lakmini YapaSenior Registrar (Medical Microbiology)
04/11/23 Y3S2 Infection 2
Infections of CVS
Infective endocarditis (IE) is defined as an infection of Infective endocarditis (IE) is defined as an infection of the endocardial surface of the heart, which may include the endocardial surface of the heart, which may include one or more heart valves, the mural endocardium, or a one or more heart valves, the mural endocardium, or a
septal defect.septal defect.
Infective Endocarditis
Types of IE
• Native Valve IE
• Prosthetic Valve IE
• Intravenous drug abuse (IVDA) IE
• Nosocomial IE
• Pace maker
Native valve endocarditis (NVE)
• Rheumatic valvular disease (?% in SL. 20% industrialized countries where RF is now uncommon)
• Congenital heart disease (15% of NVE) - PDA; VSD; Fallot tetralogy; any native or surgical high-flow lesion.
• Mitral valve prolapse with an associated murmur (20% of NVE)
• Degenerative heart disease - Including calcific aortic stenosis due to a bicuspid valve, (50% of IE in elderly)
Causative agents of NVE
Prosthetic valve
• 20% of IE• 5% of prosthesis become infected• Early onset – ≤ 1 yr after surgery CoNS S. aureus including MRSA
• Late onset – Viridans streptococcus
IVDA
• In 75% no underlying valve abnormality
• 50% involve tricuspid valve• S aureus - commonest aetiological
agent• Present with recurrent IE• May involve multiple valves
Nosocomial
• Right sided endocarditis associated with ‘long’ lines
• Associated with a previously damaged valve – left sided
• Most often, S aureus
Pacemaker endocarditis
• infections of implantable pacemakers & cardioverter-defibrillators. Usually, infected within a few months of implantation
CoNS 42%
S.aureus 29%
Clinical Features
• Fever - > 80%• Anorexia, weight loss• Embolic phenomena• Immunologic - glomerulonephritis, Osler
nodes, Roth spots.• Vascular - septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, Janeway
lesions
Janeway leisons
Osler nodes
Splinter haemorrages
Roths spots
Infective Endocarditis
Modified Duke’s criteria1. Pathologic criteria Microorganisms: shown by culture or histology in a
vegetation histology showing active endocarditis
2. Clinical criteria 2 Major criteiraOR
1 major criterian + 2 minor criteria
OR5 minor criteria
Major criteria1. Blood culture - 2 positive blood cultures with
compatible organism2. ECHO cardiography – oscillating mass,
abscess, dehiscence of prosthetic valve
Minor criteria
1. predisposing heart disease2. fever > 38°C3. vascular phenomena4. immunologic phenomena5. blood culture / ECHO not meeting above
criteria
Microbiological diagnosis• Blood culture
– Pre- antibiotic– at least 2 sets (aerobic + anaerobic) - anaerobic not
done in Sri Lanka at present– Proper preparation of skin prior to taking blood– adequate volume
• Serology - for rare causes of IE - eg: brucella, Coxiella burnetii
• PCR – not done routinely
ProblemsContamination
Negative blood cultures
Blood culture technique
• Clean the venepuncture site with 70% alcohol and allow to dry .
• Wipe concentrically starting from center with 7.5% povidone iodine. Allow to dry for 2 min.
• Wash hands with soap and water and wear sterile gloves.
• Draw blood using disposable sterile needle and syringe.
• Thoroughly mix bottles to avoid clotting.
Blood volume – manufactures instructions
Adults – 6 -10 ml / bottle Children – 3 – 5 ml Neonates – 1 ml
Treatment
• Needs to be bactericidal
• Needs to be prolonged
• Antibiotic choice dependent on likely causative organisms
• Use guidelines for antibiotic choice / dose / duration
• Treatment of complications
Prophylaxis • Principle of prophylaxis
– 2 risk factors - bacteraemia / cardiac– antibiotic indicated if both present
• Practice of prophylaxis – AHA 2007 IE is much more likely to result from frequent exposure to random
bacteremias associated with daily activities than from bacteremia caused by a dental, GI tract, or GU tract procedure. dental procedures is reasonable only for patients with underlying cardiac
conditions associated with the highest risk of adverse outcome from infective endocarditis.
Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a genitourinary or gastrointestinal tract procedure
• Important preventive measures – Routine dental care in all those with cardiac risk
Cardiac conditions for which prophylaxis is reasonable
• Prosthetic cardiac valve or prosthetic material used for cardiac valve repair
• Previous IE• Congenital heart disease (CHD)*• Cardiac transplantation recipients who
develop cardiac valvulopathy
Myocarditis• Definition - inflammation of the cardiac muscle• Clinical presentation – often asymptomatic
– acute / chronic• Aetiology
Infective Viruses – enterovirusesBacterial – C diphtheriae (toxin)Parasitic – chagas disease
Inflammatory Many autoimmune diseasesDrugs Cytotoxic drugs
‘allergic’ reactions
Myocarditis• Diagnosis
– often asymptomatic– acute cardiac symptoms – cardiac failure
• Management – Mainly symptomatic
Evidence of myonecrosis
- cardiac enzymes
Evidence of cardiac malfunction
- ECG
Evidence of aetiology
- very difficult - endomyocardial biopsy - post-mortem
Pericariditis
Evidence of pericarditis•Pericardial pain•Pericardial rub•ECG
• Acute pericarditis - isolated entity or as the result of a systemic disease.
• Incidence of pericarditis • postmortem studies 1% - 6 %• ante mortem diagnosis only 0.1% of hospitalized patients and 5%
of patients with chest pain but no myocardial infarction.• The possible sequelae of pericarditis include cardiac tamponade, recurrent pericarditis, and pericardial constriction.
Infection – Blood vessels• Cannula site infections• Endothelial infections
measles, dengueRickettsia
• Immune vasculitisHIV Hepatitis B
• Atherosclerosis Chlamydia pneumoniae Chlamydiae pneumoniae