Cardio ID Flashcards
Most common organisms for infective endocarditis
- Most Common: staph aureus, viridians group strep (dental), coagulase negative staph, enterococci, strep bovis
- IVDU: staph aureus, gram negative bacilli or polymicrobial infections
- Prosthetic Valve: staph aureus, coagulase negative staph, enterococci or gram-negative bacilli
○ If patient grows enterococcus, may come from the gut and indicate colorectal cancer, requiring a colonoscopy - Native Valve:
○ Strep Viridians (sanguis, oralis, salivarius), enterococci, staphylococci
○ HACEK: fastidious gram negatives (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella,
Treatment for infective endocarditis
IV benpen + fluclox + gen for 6 weeks unless
- Native tricuspid valve S aureus without lung abscess - 2 weeks
- Q fever, Whipples - months/years
Indications of surgical management
- Cardiac failure or highly likely to develop
- Abscess
- Failing medical therapy - many days of bacteraemia
- modifying factors (prosthetic valves, virulent organism, fit for surgery/re-do)
Absolute
• Severe aortic or mitral regurgitation
• Cardiac failure (related to valve dysfunction)
• Fungal or highly resistant organisms (VRE, MRSA)
• Perivalvular abscess or fistula
• Prosthetic valve endocarditis
Relative
• Multiple or severe embolism (on therapy)
• Uncontrolled infection (e.g., MSSA, Pseudomonas, Q fever)
• Size of vegetation (>1cm)
Modified Duke Criteria
2 major or 1 major + 3 minor or 5 minor
MAJOR
MICRO
- Typical organisms x2 cultures: S aureus, S viridians, HACEK, enterococcus, S gallolyticus
- Other organism
- Coxiella burnetii serology/CPR/culture
ENDOCARDIAL (ECHO)
- New valvular regurgitation
- Abscess
- Dehiscence of valve
- Vegetation
MINOR
- Fever > 38
- Predisposition: prosthetic valve, IVDU
- Vascular: emboli, mycotic aneurysm, Janeway
- Immune: GN, RF, Osler, Roth
Endocarditis Prophylaxis
Antibiotic prophylaxis against infective endocarditis is recommended only for patients who meet both of the following criteria:
(1) Have a cardiac condition associated with an increased risk of developing infective endocarditis and the highest risk of adverse outcomes from endocarditis
(2) Undergoing a procedure associated with a high risk of a bacteraemia that is associated with endocarditis
(1) High risk cardiac condition
- Prosthetic cardiac valve
- Prosthetic material used for cardiac valve repair
- Previous IE
- Congenital heart disease but only if it involves
(a) Unrepaired cyanotic defects including palliative shunts
(b) repaired defects with residual defects at or adjacent to the site of a prosthetic patch
(c) repair < 6m ago with prosthetic
- Rheumatic heart disease and also ATSI/Maori/Pac Islander
(2) Procedures
- Dental procedures - extraction, periodontal surgery, reimplant tooth
- Tonsillectomy, adenoidectomy
- Infected skin
- Established UTI
Tx:
- Amoxicillin 60 mins before
- If hypersensitive to penicillin - cefalexin
Acute Rheumatic Fever
- Acute systemic autoimmune disease secondary to streptococcal pharyngitis (group A β-haemolytic streptococcus - streptococcus pyogenes) → rheumatic carditis → rheumatic heart disease.
- Usually occurs 2-3 weeks post-infection; tends to recur if untreated.
- Skin (scabies/impetigo), pharyngitis
Group A strep-M protein and N-acetyl beta-D-glucosamine epitope cross-reactivity with myosin, laminin (heart) and basal ganglia plus immune complexes (joints)
Genetic predisposition for rheumatic fever
HLADR7
HLADQA1
HLADQB1
Jones criteria for rheumatic fever
Evidence of Group A B-haemolytic streptococcus (ASOT) and 2 MAJOR or 1 MAJOR + 2 MINOR
MAJOR (JONES)
- Polyarthralgia
- Carditis
- Subcutaneous Nodules
- Erythema marginatum
- Sydenham chorea
MINOR (PEACE)
- Previous rheumatic fever
- ECG with prolonged PR interval
- Arthralgias
- CRP/ESR elevated
- Elevated Temp Fever > 38
Which valve is normally affected in RHD?
Mitral
Aortic
Investigations for Group A B haemolytic strep
- ASOT: for Group A Streptococcus bacteria (Streptococcus pyogenes).
- ASO and anti-DNAse B are the most common antibodies produced by the body’s immune system in response to a Group A streptococcal infection
- Associated with Aschoff bodies (granuloma with giant cells - blue arrows) which are inflamed areas in the myocardial tissue - they are areas of fibrinoid necrosis and contain immune cells and Anitschkow cells (enlarged macrophages with ovoid, wavy, rod like nucleus (like a caterpillar)) - red arrows), increased anti-streptolysin O (ASO) titres
Treatment for acute rheumatic disease
- Single dose IM benzathine benzylpenicillin to clear Group A strep
- Arthralgia: high dose aspirin or naproxen
- Chorea: anti-epileptics or anti dopamine agents
Causes of culture negative IE
- IE with 3 –ve BC after 7 days
- Previous antibiotics or cultures not taken
- Inadequate lab or investigations
• Fastidious organism
Q fever, Bartonella, Streps, Legionella, Whipples,
Mycoplasma hominis, Chlamydophila, fungi, Brucella
• (Not HACEK now)
• Role of NAT incl. 16S PCR (or 18S PCR for fungi
Endocarditis prophylaxis
- Current recommendations are ONLY for prosthetic valves, previous endocarditis, cyanotic congenital heart disease and some high risk lesions eg patent ductus
- Post rheumatic fever exposure – daily penicillin for at least 10 years or until age 40, whichever is LONGEST.
Commonly affected valve in IE
- IVDU: route of infection from skin to systemic veins → Right Atrium → Tricuspid Valve → right ventricle → pulmonary arteries (septic PE)
- Otherwise mitral valve is most commonly affected
- If aortic valve affected - it is very close to AV node and so ECG should be checked to look for heart block
Which valve defect is most commonly associated with Infective Endocarditis? Mitral stenosis Mitral valve prolapse Aortic stenosis Tricuspid regurgitation Aortic regurgitation
Mitral valve prolapse with regurgitation
