Infective Endocarditis Flashcards
What is infective endocarditis?
It is the infection of the endocardial surface of the heart involving the heart valves +/- Mural endocardium +/- septal defect
What are the 4 main complications of infective endocarditits?
Valvular failure
Heart failure
Sepsis
Embolic disease
One of the major complications of IE is embolic disease. What could this lead to?
Stroke, MI, mycotic aneurysm, AKI, Liver injury, distal embolus (blue toe syndrome)
What side of the heart is more affected in IE?
Which valve is most effected?
Left side > Right side (95% are left sided)
Mitral > Aortic valves
Explain the pathophysiology of infective endocarditis
The endocardial surface or valves become infected after exposure to microemboli from bacteria or fungi circulating in the blood stream. Previously damaged tissue (previous IE, surgery) or non-native valves predispose to this infection
These organisms proliferate in the evolving thrombus + Persistent shedding into the blood stream causes an immune response resulting in symptoms
Vegetations in the valves causes valvular destruction and failure
What are the RFs for infective endocarditis?
Patient factors:
Age>60
Immunocompromised (DM, chemo, splenectomy, sickle cell, transplant, HIV)
Pathology:
Congenital/Structural heart disease
Valvular heart disease
Previous IE
Bowel Cancer
Procedure:
IVDU
Surgical procedure (valvular replacement, stent, and even if not cardiac)
Termination of pregnancy
Haemodialysis
Failure of aseptic technique
What is the most common organism causing IE?
What is the most common organism causing IE in Prosthetic valves?
What is the most common organism causing subacute IE?
What is the most common organism causing IE in a patient with lower GI/GU disease and bowel malignancy?
Staph aureus is the most common
Strep epidermidis and aureus are most common in prosthetic valves
Strep viridans is most common in subacute disease
Enterococci (Faecalis and Faecium) for GI/GU disease and bowel malignancy
What are the organisms that are most likely involved in IE?
Staph aureus is the most common
Strep epidermidis and aureus are most common in prosthetic valves
Strep viridans is most common in subacute disease
Enterococci (Faecalis and Faecium) for GI/GU disease and bowel malignancy
Coxiella (needs only 1 positive culture)
Fungi in immunocompromised patients
HACEK group in 2% of cases
What murmurs are most a/w IE?
AR or MR are most associated with IE (remember left sided and vegetations)
Are Osler nodes painful or painless?
Where are they typically located?
Painful and palm, pads of fingers and toes
Are Janeway lesions painful or painless?
Where are they typically located?
Painless (and haemorrhagic) on the palms of hand and soles of foot
Go through the signs and symptoms of IE
Symptoms: Fever, night sweats, anorexia, weight loss, Myalgia
In advanced disease, HF: SOB/dyspnoea, PND, orthopnoea, chest pain, cough with pink, frothy sputum
Signs: FROM JANE
Fever
Roth Spots
Osler Nodes
(New) Murmur - typically left sided
Janeway lesions
Anaemia
Nailbelt haemorrhages
Embolic (Stroke, MI, mycotic aneurysm, AKI, Liver injury, distal embolus)
+ clubbing, poor dentition, and scars of previous cardiac surgery on closer inspection
+ Splenomegaly on palpation (mild)
What are the major criteria in Duke’s criteria?
Major:
a) Blood cultures: 2 separate cultures of typical organisms
or 1 culture of coxiella
b) Imaging:
TOE ECHO 2V2A: showing vegetations or valvular perforation or Abscess or Aneurysm/pseudoaneurysm
Cardiac CT: Paravalvular lesions
PET CT FDG: Abnormal activity around prosthetic valve
What are the minor criteria in Duke’s criteria?
Minor Criteria:
a) Fever >38
b) Microbiology evidence but inadequate for major
c) Predisposing factors (tissue damage, previous IE…)
d) Vascular phenomena (emboli/thrombosis)
e) Immunological phenomenon (osler’s, Janeway lesions, Glomerulonephritis)
What is required for a Definite IE dx vs probable?
Definite if:
a) Pathological evidence on histology of vegetations or intracardiac abscess
b) 2 major criteria
c) 1 major + 3 minor
d) all 5 minor
Probable if:
a) 1 major + 1 minor
b) 3 minor
