Infective endocarditis Flashcards
What are symptoms of acute infective endocarditis?
1) spiking fevers
2) tachycardia
3) fatigue
4) progressive damage to cardiac structures
What valves are usually affected?
Aortic 5-36% Mitral 28-45% Aortic and mitral 0-35% Tricuspid 0-6% Pulmonary <1%
Reduction in rheumatic heart disease → less mitral valve endocarditis seen
Increase in IV drug use → more tricuspid valve endocarditis seen
Who is at risk of infective endocarditis?
- high risk
- moderate risk
- low risk
High risk
- Prosthetic valves (s aureus, coagulase –ve S)
- Cyanotic congenital heart disease
- Intravenous drug use (s. aureus)
- Previous infective endocarditis
Moderate risk
- Valvular heart disease - Aortic disease; Mitral regurgitation
- Congenital heart disease - VSD; Bicuspid aortic valve; PDA, coarctation
- HOCM
Low risk
- Atrial septal defect
- Mitral calcification
- Intra-cardiac electronic devices ICED – e.g. pacemakers
- (CABG = no risk)
What may happen to structures in the heart?
valve leaflet may be destroyed / may have hole in valve
chordae tendineae may rupture
What organisms causes endocarditis?
40% Staphylococci – grape like clusters
30% Streptococci – cocci chain
11% Enterococci
2% Fungi
2% polymicrobial
10% culture negative
What organisms should you suspect in native valve endocarditis?
enterococci
viridans group streptococci
staph aureus
Rarely HACEK - haemophilus actinobacillus, cardiobacterium, eikenella, kingella
What organisms should you suspect in IVDU?
Fungi - candid, aspergillus
What organism should you suspect in SLE?
Libman-Sacks endocarditis
When should you suspect endocarditis?
Fever + new murmur = endocarditis until proven otherwise
How would sub-acute and acute presentation of infective endocarditis differ?
Sub-acute
• Gradual onset fever, fatigue, sweats, weight loss
•Usually with known congenital or valve disease
•May have clubbing, splenomegaly, haematuria
•May have stigmata of chronic endocarditis
•Classically caused by streptococci
Acute
•Rapid onset, severe febrile illness
•Cardiac murmur
•Stigmata of chronic endocarditis absent
•May present with emboli, cardiac failure, and/or renal failure
•Stroke, septic joint, splenic infarct
•Highly pathogenic organisms e.g. Staph aureus
Common features: Non-specific •Malaise •Fever - 96% of cases •Sweating •Anorexia •Weight loss (malignancy is often suspected)
What classical signs would you expect to find on examination
Splinter haemorrhages
- Linear haemorrhages
- Similar to peripheral petechiae
- Distal nail bed
- Nonspecific – may be due to trauma
Osler’s nodes
- Painful, peripheral nodulae haemorrhagic or erythematous lesions of distal phalanges
- Due to immune complex deposition
- May be seen in systemic vasculitis
Janeway lesions
- Similar appearance and pathogenesis to Osler nodes
- Located on palms and soles
- NOT painful
- Can be transient
- May ulcerate or become haemorrhagic
Mucosal petichieae - Can be seen when pull eyelid down
Roth’s spots
- Small haemorhaggic lesion with central pallor
- May be seen in conditions associated with vasculitis (e.g. SLE)
Splinter haemorrhages
- Linear haemorrhages
- Similar to peripheral petechiae
- Distal nail bed
- Nonspecific – may be due to trauma
Osler’s nodes
- Painful, peripheral nodulae haemorrhagic or erythematous lesions of distal phalanges
- Due to immune complex deposition
- May be seen in systemic vasculitis
Janeway lesions
- Similar appearance and pathogenesis to Osler nodes
- Located on palms and soles
- NOT painful
- Can be transient
- May ulcerate or become haemorrhagic
Mucosal petichieae
- Can be seen when pull eyelid down
Roth’s spots
- Small haemorhaggic lesion with central pallor
- May be seen in conditions associated with vasculitis (e.g. SLE)
How would you diagnose infective endocarditis?
Definite IE
Pathological criteria
Microorganisms demonstrated by culture or histological examination of vegetation, a vegetation that has embolized, or an intracardiac abscess specimen; or pathological lesions; vegetation or intracardiac abscess confirmed by histological examination showing active endocarditis
Clinical criteria
2 Major criteria, 1 major criterion and 3 minor criteria, or 5 minor criteria
Possible IE
-1 Major criterion and 1 minor criterion, or 3 minor criteria
MAJOR
- Blood Cultures with typical organisms
- Evidence of endocardial involvement – abnormal Echo or new valvular regurgitation
MINOR
- Predisposing condition (e.g. valvular abnormality, CHD) or IVDU
- Fever (common and non specific)
- Immunological phenomena e.g. vasculitis, rash, splinters, Roth spots
- Vascular phenomena e.g. Embolism; Janeway lesions
- Other microbiological criteria
What investigations should you do in infective endocarditis?
History, clinical exam, haematuria
FBC→ normochromic, normocytic anaemia, neutrophilia, high ESR/ CRP, positive rheumatoid factor
- Blood cultures → 3 sets at different times from different sites at peak of fever (1 hour apart)
ECG→ prolonged PR interval/ AV block if aortic root abscess
ECHO → valvular, mobile vegetations.
- TOE more sensitive for mitral lesions/aortic root abscess
CXR→ pulmonary oedema, cardiomegaly
Sometimes specific microbial tests
- E.g. suspected Q fever
Urinalysis→ RBC/WBC casts, proteinuria from septic emboli
When should you suspect infective endocarditis?
- A febrile illness and a murmur of new valvular regurgitation;
- A febrile illness, a pre-existing at-risk cardiac lesion (see Figure 2) and no clinically obvious site of infection;
- A febrile illness associated with any of:
- Predisposition and recent intervention with associated bacteraemia,
- Evidence of congestive heart failure,
- New conduction disturbance
- Vascular or immunological phenomena: embolic event, Roth spots, splinter haemorrhages, Janeway lesions, Osler’s nodes,
- A new stroke,
- Peripheral abscesses (renal, splenic, cerebral, vertebral) of unknown cause; - A protracted history of sweats, weight loss, anorexia or malaise and an at-risk cardiac lesion;
- Any new unexplained embolic event (e.g. cerebral or limb ischaemia);
- Unexplained, persistently positive blood cultures;
- Intravascular catheter-related bloodstream infection with persistently positive blood cultures 72 h after catheter removal
What conditions places someone at risk of infective endocarditis?
- Valvular heart disease with stenosis or regurgitation
- Valve replacement
- Structural congenital heart disease, (even if surgically corrected or palliated)
- Structural conditions, but excluding isolated atrial septal defect, fully repaired ventricular septal defect or fully repaired patent ductus arteriosus, and closure devices that are judged to be endothelialized
- Previous infective endocarditis
- Hypertrophic cardiomyopathy
- Intravenous drug users
- Patients with implantable cardiac electronic devices e.g. pacemakers
What is the guidelines on blood cultures in infective endocarditis?
- Blood cultures should be taken prior to starting treatment in all cases.
- Aseptic technique - reduce risk of contamination with skin commensals
- In patients with chronic or subacute presentation, 3 sets of blood cultures should be taken from peripheral sites with ≥6 h between them prior to commencing antimicrobial therapy.
- In patients with suspected IE and severe sepsis or septic shock at time of presentation, 2 sets of optimally filled blood cultures should be taken at different times within 1 h prior to commencement of empirical therapy
- Once on antibiotics - antibiotic therapy may need to be stopped for 7–10 days before blood cultures will become positive again. Patients often too ill to do this.
- Include risk factors for endocarditis with clinical details on request - prosthetic valves; ICEDs as alter interpretation of results for possible skin contaminants.
What should you do if you suspect infective endocarditis in a patient?
Ask for cardiology opinion
- do not request an ECHO
How long does antibiotic treatment usually last?
4-6 weeks of IV antibiotics
Blind therapy: native/prosthetic implanted
Blind therapy: native/prosthetic implanted >1yr→ ampicillin, flucloxacillin, gentamicin (if Gram -ve, meropenem and vancomycin)
