Infective Endocarditis Flashcards
What is infective endocarditis?
Involving the endocardial surface of the heart, including the valvular structures, the chordae tendineae, sites of septal defects, or the mural endocardium.
What are the most common pathogens causing infective endocarditis?
- Viridans group streptococci.
- Staphylococcus aureus.
- Enterococci.
- Coagulase-negative staphylococci.
- Haemophilus parainfluenzae.
What are the risk factors for infective endocarditis?
- Prior history of infectious endocarditis
- Presence of artificial prosthetic heart valves
- Certain types of congenital heart disease
- Post-heart transplant
- IV catheter
- IV drug use
- Recent dental or surgical procedure
What are the signs of infective endocarditis?
- Tachycardia
- Meningeal signs
- Cardiac murmur
- Janeway lesions
- Osler nodes
- Roth spots
What are the symptoms of infective endocarditis?
- Fever and chills
- Night sweats
- Fatigue
- Anorexia
- Weight loss
- Weakness
- Arthalgia
- Headache
- Dyspnoea
Briefly describe Janeway lesions
Haemorrhagic, macular, painless plaques with a predilection for the palms and soles
Briefly describe Osler nodes
Small, painful, nodular lesions usually found on the pads of the fingers or toes
Briefly describe Roth spots
Oval, pale, retinal lesions surrounded by haemorrhage detected on fundoscopy
Briefly describe splinter haemorrhages
A longitudinal, red-brown haemorrhage under a nail
What investigations should be ordered for infective endocarditis?
- FBC
- Serum chemistry panel with glucose
- Urinalysis
- Blood cultures
- ECG
- Echocardiogram
- CXR
- CT
Why investigate FBC?
Most patients have a normocytic, normochromic anaemia.
Leukocytosis is seen in about one third of cases often with neutrophilia.
Why investigate serum panel with glucose?
Provides baseline assessment.
May shown normal or elevated urea.
Why investigate urinanlysis?
Septic emboli are common complications of IE, and urinalysis may demonstrate active sediment assisting in the clinical diagnosis.
RBC casts; WBC casts; proteinuria; pyuria.
Why investigate blood cultures?
It is generally recommended that 3 sets of blood cultures be obtained 1 hour apart prior to initiating antibiotic therapy to ensure greatest yield. The most common cause of culture-negative endocarditis is antibiotic therapy preceding blood cultures.
Bacteraemia; fungaemia.
Why investigate ECG?
Progression of the infection may lead to conduction system disease.
May show prolonged PR interval; non-specific ST/T wave abnormalities or AV block.