Infective Endocarditis Flashcards
What is infective endocarditis?
Infection of the endocardium, heart valves, IV septum, chordae tendinae or intra-cardiac devices
What are the aetiologies?
Rheumatic heart disease
Mitral valve prolapse +/- regurgitation
VSD
Prosthetic heart valve
What is the pathophysiology in adherence and invasion of non bacterial thrombotic endocarditis?
Sterile platelet-fibrin vegetation can occur on damaged or undamaged endothelium
ON DAMAGED - fibrin adheres causing a coagulation cascade leading to bacteria latching on and brings in macrophages
ON UNDAMAGED - inflammation in lining of endothelium causes bigger and invasive vegetation
What is the pathophysiology in mechanical disruption of valve endothelium?
Turbulent blood flow Catheters Electrodes Degenerative Inflammation
What is the pathophysiology in physically normal endothelium?
Local inflammation
What is the pathophysiology in bacteraemia?
Extra cardiac infections such as chest infections and UTIs
Invasive procedures and daily living
What are the classifications of endocarditis?
Acute - staph aureus causative organism, patients very sick
Sub acute - streptococci
Chronic
What is included in the history of a patient with suspected endocarditis?
Specifics of bacteraemic episode - surgery, dentist Fever New murmur Known causative organism Prosthetic material - PPM, ICD, prosthetic valve CHD New conduction disorder IVDA
What are the non specific symptoms?
Fever
Fatigue
Malaise
What are the signs?
May be absent Congestive cardiac failure Janeway lesions Osler's nodes Roth spots
What are the investigations?
MARKERS of INFECTION - FBC, CRP, Us+Es
BLOOD CULTURES - prior to starting antibiotics, 3 sets from different sites, 6 hours apart or 2 sets from different sites 1 hour apart if sepsis/shock
URINALYSIS - proteinuria, haematuria
ECG - conduction delay
CHEST XRAY - heart failure, pulmonary abscess
ECHOCARDIOGRAM - TTE +/- TOE, TTE first line if normal and high clinical suspicion then also TOE, repeated to assess and see complications
What is the microbiology?
Strep, entero, staph
What are the major criteria in the modified duke criteria?
Identifying organism
Evidence of infection in heart
Echo
New murmur
What are the minor criteria?
Endocarditis complex of clinical findings Predisposing heart condition IVDU Fever Vascular phenomenon Immunological phenomenon
What is needed for diagnosis using modified duke criteria?
2 major
1 major and 3 minor
5 minor
Possible if 1 major or 3 minor
