Infective Endocarditis & Rheumatic Fever Flashcards
Describe the pathogenesis of bacterial endocarditis and those at risk of developing infective endocarditis
People at risk:
1.Age above 60years
2.Male sex
3.Injection drug use
4. poor dentition or dental infection
more common in older patients with degenerative heart valve disease or with cardiac prosthetic valves. Common organism: virulent Staphylococci
Discuss the major aetiological agents of infective endocarditis.
● Discuss diagnosis andcomplications of endocarditis.
● Describe why a blood culture is the single most important test to diagnose the causative organism and how it should be taken.
● Discuss the principles of antibiotic therapy in treatment of infective endocarditis.
Discuss concept of prophylactic antibiotics in people with heart defects
what is endocarditis ?
inflammation of the inner lining of the hearts chamber and valves
and its life threatening
Is Routine dental cleaning a risk factor for Infective endocarditis?
Dental procedures that involve manipulation of gingival tissue or the peripheral region of teeth.
Describe the pathogenesis of Infective endocarditis?
In summary, predisposing conditions such as underlying heart disease predispose to endothelial damage of the valves then thrombi is formed. Circulating infective organism will then attach to these thrombi and then proliferate. Vegetations will then be formed. It can embolize and form abscess at distant sites
which bacteria is more common in intravenous drug abusers and patients with long-term indwelling catheters e.g.
patient on hemodialysis.
streptococcus Aureus.
Blood culture negative organisms include:
mixture of fastidious bacteria, zoonotic bacteria and fungi.
HACEK BACTRIA
ORGANISM THAT COLONIZE THENOROPHARYNX.
CLINICAL OF INFECTIVE ENDOCARDITIS
fever with chills, loss of appetite and weight loss
heart murmurs
embolic pneumonia.
in South Africa most patient IE presents with.
clubbing, splinter haemorrhages and glomerulonephritis
when to suspect right sided IE?
often seen in intravenous drug abusers, immunosuppressed patients, patients with indwelling lines or pacemaker leads, has the additional complication of septic emboli to the lungs
Chest X-ray features of septic emboli: “multiple, bilateral areas of opacification with air-fluid levels due to tissue breakdown
what is the common cause of right-sided IE
staphylococcus aureus
Most common site for infective endocarditis is the
left valve.
Diagnosis- Modified Duke Criteria (VERY IMPORTANT
Definite IE= 2 major OR 1 major and 3 minor OR 5 minor
Possible IE= 1 major and 1 minor OR 3 minor
what are major criteria
- positive blood cultures
- Imaging
minor criteria
1.Predisposing heart condition or intravenous drug use
2.Fever > 38°C
3.Vascular phenomena: arterial emboli, splenic infarction, mycotic aneurysms, intracranial haemorrhage and Janeway lesions (including those detected by imaging alone
4.Immunological phenomena: glomerulonephritis,
Osler’s nodes, Roth’s spots & rheumatoid factor
5.Microbiological evidence: positive blood cultures not meeting major criteria above or serological evidence of infection with organism consistent with IE
Blood cultures
Microorganisms consistent with IE from two microorganism consistent with IE from two separate blood cultures:
1.viridans group streptococci, Streptococcus bovis group, HACEK group, Staphylococcus aureus; or
Community-acquired enterococci with absence of primary focus
separate blood cultures:
2.viridans group streptococci, Streptococcus bovis group, HACEK group, Staphylococcus aureus; or
Community-acquired enterococci with absence of primary focus
Imaging
Transthoracic echocardiography (TTE)- initial choice for both native valve and prosthetic valve IE
Transoesophageal echocardiography (TEE) - better demonstrates complications such as abscess, perforations AND Fistulae
role of echo: detect features suggestive of IE, detect valve abnomarlity
postive role finding: Mobile masses or vegetations on heart valves.
Nontender,erythematous papules
Janeways lession
The cornerstone of Diagnosis of IE.
positive blood culture.
Echocardiography features.
cardiac complication of IE
heart failure
perivascular abscess
pericarditis
intracardiac fistula
>metastatic abscess, spleen, kidney, brain
> Mycotic aneursym
Neurologic complication of IE
Embolic stroke
brain abscess or cerebritis
purulent or aseptic meningitis
cerebral haemorrhage
seizures (secondary to abscess or embolic infarction).
Renal complication of IE
renal infarction
renal abscess
renal failure
Musculoskeletal complication of IE
VERTEBRAL osteomyelitis
septic arthritis.
pulmonary complications of IE
most common with right-sided endocarditis
bacterial pneumonia
lung abscess
pyothorax
pleural effusion
pneumothorax.
Management - general approach.
Prompt diagnosis and initiation of antimicrobial therapy
Antithrombotic therapy
Need to remove source e.g. infected implanted device
Identify need for early valve surgery
Monitor response to antibiotic therapy
Monitor hemodynamic and cardiac status e.g. surveillance ECGs
Follow-up and prevention of recurrent IE including good dental hygiene, antibiotic prophylaxis
