Infective Endocarditis Flashcards
What is infective endocarditis?
Infective endocarditis is an infection of the endocardial surface of the heart, including the heart valves.
What are the common causative organisms of infective endocarditis?
Staphylococcus aureus, Streptococcus viridans, Enterococcus species, and HACEK organisms.
What are the risk factors for infective endocarditis?
Prosthetic heart valves, congenital heart disease, previous endocarditis, intravenous drug use, and immunosuppression.
What are the typical symptoms of infective endocarditis?
Fever, night sweats, fatigue, weight loss, malaise, and new or worsening heart murmur.
What are the classic signs of infective endocarditis on physical examination?
Janeway lesions, Osler nodes, Roth spots, splinter haemorrhages, and clubbing.
What are Janeway lesions?
Non-tender, erythematous macules on the palms and soles caused by septic emboli.
What are Osler nodes?
Painful, red, raised lesions on the fingers and toes caused by immune complex deposition.
What are Roth spots?
Retinal haemorrhages with a pale centre seen on fundoscopy in infective endocarditis.
What is the pathophysiology of infective endocarditis?
Bacteria or fungi adhere to damaged endocardium, forming vegetations composed of microorganisms, fibrin, and platelets.
How is infective endocarditis classified?
It is classified as acute (rapid onset, severe symptoms) or subacute (slower onset, milder symptoms).
What are the complications of infective endocarditis?
Heart failure, systemic embolism, stroke, renal failure, and abscess formation.
What investigations are used to diagnose infective endocarditis?
Blood cultures, echocardiography (transthoracic or transoesophageal), and blood tests (e.g., inflammatory markers).
What is the role of blood cultures in diagnosing infective endocarditis?
Blood cultures identify the causative organism and guide antibiotic therapy; at least three sets are required.
What is the role of echocardiography in infective endocarditis?
Echocardiography detects vegetations, valvular abnormalities, and complications like abscesses.
What are the Duke criteria for infective endocarditis?
Diagnostic criteria including major criteria (positive blood cultures, evidence of endocardial involvement) and minor criteria (e.g., fever, vascular phenomena).
How is infective endocarditis treated?
High-dose intravenous antibiotics based on blood culture results, and surgery if indicated (e.g., valve replacement).
When is surgical intervention indicated in infective endocarditis?
Persistent infection, heart failure, large vegetations, or complications like abscesses or embolic events.
What are the indications for prophylaxis against infective endocarditis?
Patients with prosthetic heart valves, previous endocarditis, or certain congenital heart defects undergoing high-risk dental or surgical procedures.
How does intravenous drug use increase the risk of infective endocarditis?
It introduces pathogens directly into the bloodstream, often causing right-sided endocarditis (tricuspid valve).
What are splinter haemorrhages, and how are they related to infective endocarditis?
Linear, reddish-brown streaks under the nails caused by microvascular emboli.
What is the difference between left-sided and right-sided infective endocarditis?
Left-sided endocarditis affects systemic circulation and organs like the brain, while right-sided endocarditis typically causes pulmonary emboli.
What blood test abnormalities are common in infective endocarditis?
Elevated inflammatory markers (CRP, ESR), anaemia, and sometimes abnormal renal function or positive rheumatoid factor.
What are HACEK organisms?
A group of fastidious Gram-negative bacteria (e.g., Haemophilus, Aggregatibacter) that can cause infective endocarditis, particularly in prosthetic valves.
What is the prognosis of infective endocarditis?
Prognosis depends on early diagnosis and treatment but is poorer in cases with complications or delayed treatment.
