Infective endocarditis Flashcards
What is infective endocarditis?
Infective endocarditis refers to infection of the endothelium (inner surface) of the heart, most commonly affecting the heart valves.
What are the risk factors for infective endocarditis?
Risk factors include:
* Intravenous drug use
* Structural heart pathology (e.g., valvular heart disease, congenital heart disease)
* Chronic kidney disease (especially on dialysis)
* Immunocompromised (e.g., cancer, HIV, immunosuppressive medications)
* History of infective endocarditis
What structural pathologies can increase the risk of infective endocarditis?
Structural pathologies include:
* Valvular heart disease
* Congenital heart disease
* Hypertrophic cardiomyopathy
* Prosthetic heart valves
* Implantable cardiac devices (e.g., pacemakers)
What is the most common cause of infective endocarditis?
The most common cause is Staphylococcus aureus.
What are some other causes of infective endocarditis?
Other causes include:
* Streptococcus (notably viridans group)
* Enterococcus (e.g., Enterococcus faecalis)
* Pseudomonas
* HACEK organisms
* Fungi
What are some common presenting symptoms of infective endocarditis?
Symptoms include:
* Fever
* Fatigue
* Night sweats
* Muscle aches
* Anorexia (loss of appetite)
What are some key examination findings in infective endocarditis?
Key findings include:
* New or “changing” heart murmur
* Splinter haemorrhages (red-brown lines along fingernails)
* Petechiae (small red/brown spots on skin and mucosa)
* Janeway lesions (painless red macules on palms/soles)
* Osler’s nodes (tender red/purple nodules on fingers/toes)
* Roth spots (retinal haemorrhages)
* Splenomegaly (in longstanding cases)
* Finger clubbing (in longstanding cases)
What is the recommended process for diagnosing infective endocarditis?
Diagnosis requires:
* Blood cultures: Three samples taken from different sites, at least 6 hours apart.
* Echocardiography: Transoesophageal echocardiography (TOE) is more sensitive than transthoracic echocardiography.
What are special imaging techniques for patients with prosthetic heart valves?
Special imaging techniques include:
* 18F-FDG PET/CT
* SPECT-CT
What is the Modified Duke Criteria for diagnosing infective endocarditis?
Diagnosis requires either:
* One major plus three minor criteria, or
* Five minor criteria.
Major criteria:
* Persistently positive blood cultures
* Specific imaging findings (e.g., vegetation on echocardiogram)
Minor criteria:
* Predisposition (e.g., IV drug use, heart valve pathology)
* Fever > 38°C
* Vascular phenomena (e.g., splenic infarction, Janeway lesions)
* Immunological phenomena (e.g., Osler’s nodes, Roth spots)
* Microbiological phenomena (e.g., positive cultures that don’t meet major criteria)
How is infective endocarditis typically managed?
Management includes:
* Intravenous broad-spectrum antibiotics (e.g., amoxicillin + gentamicin)
* Duration of antibiotics:
* 4 weeks for native heart valves
* 6 weeks for prosthetic heart valves
* Surgery may be needed for:
* Heart failure due to valve pathology
* Large vegetations or abscesses
* Infections not responding to antibiotics
What are some key complications of infective endocarditis?
Complications include:
* Heart valve damage (leading to regurgitation)
* Heart failure
* Infective and non-infective emboli (causing strokes, abscesses, splenic infarction)
* Glomerulonephritis (leading to renal impairment)
What is the prophylaxis for infective endocarditis?
Antibiotics are not routinely recommended for dental or non-dental procedures. However, case-by-case prophylaxis may be considered for high-risk patients. High-risk patients should focus on maintaining good oral health to reduce the risk of infective endocarditis.
