Infective Endocarditis Flashcards
Infective endocarditis
Infection involving the endocardial surface
What other structures can it effect (4)
- Valvular structures- native and prosthetic valve
- Chordae Tendineae
- Sites of septal defects
- Mural endocardium
Incidence
More common in men
Worse prognosis in women
MDT (6)
- Referring doctors/GPs
- Microbiologists/Infectious disease team
- Cardiothoracic surgeon
- Radiologists
- Neurologists/Neurosurgeon
- Reference centre- complicated cases
Evolving epidemiological profile
- Past- young adults (chronic/subacute course)
- Present- older patients with degenerative heart disease, healthcare associated procedure, valve diseases, congenital heart disease, prosthetic valve, IVDU, Immunocompromised patients
Risk factors for Native IE (9)
- Mitral valve disease
- Rheumatic heart disease
- Congenital heart disease
- Degenerative heart disease
- Asymmetrical septal hypertrophy
- IV drug abusers
- Alcoholic cirrhosis
- Diabetes mellitus
- Indwelling medical devices
Pathophysiology of IE in the valve endothelium (4)
Mechanical disruption exposes EM
Produces tissue factors
Deposition of fibrin and platelets
NBTE facilitates adherence and infection
Causes of damaged endothelial valve (5)
- Turbulent blood flow (venturi effect-low pressure)
- Electrodes
- Catheters
- Inflammation (rheumatoid carditis)
- Degenerative valve disease
Venturi Effect
- Reduction in fluid pressure when a fluid flows through constricted area of pipe
- High velocity and low pressure
Pathophysiology of endothelial Inflammation (3)
- Inflammation leads to expression of integrins (B1 family)
- Integrin acts like a hook that binds circulating fibronectin on staph aureus
- Adherent organisms trigger active internalisation into valve endothelial cells
Causes of Bacteraemia
Invasive procedures
Extra cardiac infections
Non invasive activities
Name 6 Causative organisms of IE
- Viridans group streptococci
- Staphylococcus aureus
- Enterococci
- Coagulase-negative staphylococci
- Streptococcus bovis
- Fungi
Classification of IE (6)
- Acute- days/weeks
- Subacute- weeks/months
- Nidus- localisation
- Mode of acquisition
- Active
- Recurrence
Localisation (2)
Left or Right sided
Native or Prosthetic valve
Mode of acquisition (4)
Nosocomical
Non Nosocomical
Community acquired
IV drug abuse
Active IE (4)
Persistent fever and positive blood cultures
Active inflammatory morphology
Histopathological evidence
Histopathological evidence of active IE
Recurrence
Relapse
Reinfection
less than 6 months since the last episode
Diagnosis (5)
- High index of suspicion
- Bacteraemia with audible murmur should raise suspicion
- Elderly or immunocompromised
- Acutely- fever, embolic signs/symptoms or decompensated HF
- Subacute fever, non-specific constitutional symptoms or palpitation
Common symptoms (6)
- Fever/chills
- Night sweats, malaise, fatigue, anorexia, weight loss
- Weakness
- Arthralgia
- Headache
- SOB
Clinical signs (10)
- Cardiac murmur (regurgitant murmur)- with signs of HF
- Janeway lesions
- Petechial haemorrhage
- Osler nodes
- Roth spot- retinal haemorrhage
- Meningeal signs
- Splinter haemorrhage
- Cutaneous infarcts
- Vasculitic rash
- Immune complex deposition
Investigations (8)
- Blood culture (3 sets and sites 30mins apart)
- FBC. ESR/CRP elevated acute inflammatory markers
- U+Es- renal failure
- Urinalysis for blood
- ECG- prolongation of PR interval >200ms
- CXR: pulmonary congestion or abscess
- MSCT, MRI, PET.CT and leucocyte SPECT/CT
- Transthoracic or transoesophageal echocardiography
Modified Duke’s Criteriea (1)
- Blood cultures positive for IE
A. Typical micororganisms consistent with IE from 2 seperate blood culture
B. Microorganisms consistent with II from persistently positive cultures
C. single positive blood culture
A. Typical micororganisms consistent with IE from 2 seperate blood culture
Viridans streptococci, Streptococcus gallolyticus (Streptococcus bovis), HACEK group,
• Staphylococcus aureus; OR
• Community-acquired enterococci, in the absence of a primary focus;
C. single positive blood culture
Coxiella burnetii or phase I IgG antibody titre >1:800
Modified Dukes Criteria (2)
Imaging positive for IE
A. Vegetation
B. Abnormal activity around the site of prosthetic valve
C. Definite paravalvular lesions by cardiac CT
A. Echocardiogram positive for IE:
- Vegetation
- Abscess, pseudoaneurysm, intracardiac fistula •Valvular perforation or aneurysm
- New partial dehiscence of prosthetic valve
B. 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.
ESC 2015 Modified Duke’s Criteria- Minor Criteria (5)
- Predisposition such as predisposing heart conditions or IV drug use
- Fever defined as temperature above 38
- Vascular phenomena
- Immunological phenomena
- Microbiological evidence
Diagnosis of definite IE (3)
- 2 major
- 1 major +3 minor
- 5 minor
Diagnosis of possible IE (2)
- 1 major + 1 minor
* 3 minors
Rejection of the diagnosis of IE
• Resolution of endocarditis with antibiotic therapy
What does the treatment depend on (3)
- Whether patient received previous antibiotic therapy
- Whether infection affects native or prosthetic valve
- The mode of infection
Treatment for community acquired native or late prosthetic valves (3)
Ampicillin
Flucloxacillin
Gentamicin
IV
Treatment for community acquired native or late prosthetic valves with penicillin allergy
Vancomycin and Gentamicin IV
Early PVE post surgery or noscomical or non-nosocomial (3)
Vancomycin
Gentamicin
Rifampin
Patient characteristics that can cause complications (4)
Older age
Prosthetic valve
DM
Comorbidity
Clinical complications of IE
HD Renal failure Ischaemic stroke Brain Haemorrhage Septic shock
Microorganism complications (3)
Staph aureus
Fungi
Non-HACEK gram negative bacilli
ECHO findings (7)
Periannular complications Severe left-sided valve regurgitation Low left ventricular ejection fraction Pulmonary hypertension Large vegetation Valve dysfunction elevated systolic pressure
Complications and Indications for Surgery (4)
- Heart failure in IE
- Uncontrolled infection
- Migration of cardiac vegetation to brain/spleen from left IE
- Pulmonary embolisms are the result of right sided IE
Principles of prevention of IE (3)
• Antibiotic prophylaxis must be limited with patients with the highest risk of IE
Patients with prosthetic valves
Previous IE
Congenital heart disease
• Good oral hygiene and regular dental review are more important than antibiotic prophylaxis to reduce the risk
• Aseptic measures
Preventative measures (7)
- Strict dental hygiene
- Disinfection of wounds
- Curative antibiotics
- No self-medication with antibiotics
- Strict infection control
- Discourage piercing and tattooing
- Limit the use of infusion catheters and invasive procedures
