IE/AS Flashcards
What is infective endocarditis?
Inflammation of the endothelial surfaces of the heart including heart valves caused by certain micro-organisms
What are the types of endocarditis?
Infective endocarditis
–> micro-organisms colonise the heart valves and form friable vegetations
–> The two types are acute and subacute
–> Diagnosis is via duke’s criteria
Non bacterial thrombotic endocarditis (marantic endocarditis)
–> Typically occurs in advanced malignancy
–> sterile vegetations on heart valves
Libman sacs endocarditis
–> Same as NBTE
–> occurs in malignancy
Why are patients with rheumatic heart disease or valve replacements more susceptible to endocarditis?
-In normal heart blood flows smoothly over the valves
-This is not the case in damaged tissues e.g. due to RHD or valve replacement, which are susceptible to bacterial colonisation
What is the pathophysiology of rheumatic heart disease?
-Acute rheumatic fever results from host response to strep A antigens which cross-react with host proteins
-In particular CD4+ T cells directed against Streptococcal M proteins recognise cardiac self antigens
-Cytokines subsequently produced by CD4+ T cells attract neutrophils and macrophages
-These are additionally attracted by antibody binding and complement activation
-Damage to heart tissue is therefore caused by combination of antibody and t cell mediated reactions
Recurrent inflammation leads to:
–> commissural fibrosis
–> valve thickening and calcification
–> Shortened and fused chordae tendinae (fish mouth shape)
What are the gross findings in endocarditis?
Acute phase: vegetations along line of closure with minimal impact on function
Chronic phase: commissure fibrosis, valve thickening and calcification, shortened and fused chordae tendinae (fish mouth shape)
Microscopic findings
Aschoff bodies
–> form of granulomatous inflammation
–> consists of central zone of degenerating extracellular matrix infiltrated by lymphocytes, plasma cells and anitschkow cells (activated macrophages also known as caterpillar cells due to wavy nuclear outlines)
–> Can be found in all 3 layers of heart (endocardium, myocardium, pericardium
What is seen macroscopically?
Aschoff nodules
Fibrinoid necrosis
What investigation is used to identify valvular vegetations?
-2D echocardiogram
What to look for on 2D echocardiogram
1) Regurgitation
2) Leaflet: thickening, coaptation failure, prolapse, reduced mobility, nodules
3) Pericardial effusion
4) mobile mass (vegetations)
Coaptation failure: coaptation is the distance of apposition of the two valve leafelets
What micro-organisms are commonly implicated?
-Strep viridans
-Coagulase negative staph (staph aureus, staph epidermidis)
-Enterococci
-Hacek group of micro-organisms (oral commensals)
How is endocarditis diagnosed?
Dukes criteria
2 major criteria and 0 minor criteria
1 major criteria and 3 minor criteria
5 minor criteria and 0 major criteria
What are the major criteria for diagnosis of infective endocarditis?
+ve blood culture suggestive of endocarditis
-2x separate positive blood cultures with suggestive organisms, 1x blood culture with coxiella burnetii, antiphase 1 antibody titre >1:800
Evidence of endocardial involvement
-Endocardium +ve for vegetations, abscess, prosthetic valvular dehiscence, new valvular regurgitation (not changing of existing murmur)
What are the minor criteria for diagnosis of infective endocarditis?
Predisposition
-IV drug use
-Heart condition
Vascular phenomena
-Major arterial emboli
-Septic pulmonary infarcts
-Mycotic aneurysm*
-Janeway lesions*
-Intracranial haemorrhage
-Conjunctival haemorrhage
Immunologic phenomena
-Glomerulonephritis
-Roth spots
-Osler’s nodes
-Rheumatoid factor
Fever
- >38 degrees
Microbiological evidence
- +ve blood culture consistent with IE but doesn’t fit major criteria
Echocardiogram
-Evidence on echocardium but does not fit major criteria
*Janeway lesion: haemorrhagic lesion on palms or soles
*mycotic aneusysm: aneurysm due to infection
-Roth spots: retinal haemorrhages
What are the risk factors for infective endocarditis?
-Valvular heart disease (stenosis/regurg)
-Structural congenital heart disease
-prostheticvalve
-Tooth extraction
-Immunosuppression (HIV)
-Rheumatic heart disease
-IVDU
What are the complications of endocarditis?
Cardiac
-AMI
-Arrythmia
-Intracardiac abscess
-pericarditis
-valvular inssuficciency
-CCF
Non cardiac
-Glomerulonephritis
-AKI
-stroke
-Mesenteric/splenic infarct
What are the signs of infective endocarditis in the hand?
Osler’s nodes:
-Raised painful lesions in fingers caused by deposition of immune complexes
Janeway lesions
-non painful macular or nodular lesions in palms and soles of foot caused by septic emboli depositing bacteria, causing microabscesses
Splinter haemorrhages
-Tiny blood clots under finger nails
What are the indications for surgery in IE?
-Abscess
-Valvular destruction/obstruction
-Haemodynamic compromise
-CCF
-Septic emboli
-Fungal infective endocarditis
-Failureof medical therapy
Signs and symptoms of IE FROM JANE
Fever
Roth spots
Osler’s nodes
Murmur
Janeway lesions
Anaemia
Nail (splinter) haemorrhage
Emboli
What is the treatment of infective endocarditis? Why is treatment challenging?
IV antibiotics for 6 weeks
Restictions
-Valves do not have specific blood supply so antibiotics struggle to reach the micro-organisms
-Micro-organisms live within vegetations
-Micro-organisms form a bio-film
What happens if endocarditis occurs in tricuspid valve?
Right sided heart failure
What is the management if there is poor response to medical therapy?
-Valve replacement
-Heart transplant
What matching is required prior to heart transplantation?
HLA matching
How can you prevent organ rejection in heart transplant patient?
Immunosuppressant therapies
-Tacrolimus
-Mycophenolate
-Steroids
What are the side effects of long term steroid use?
-Opportunistic bacterial and viral infections such as EBV, CMV, leukaemia, lymphoma
-Cushingoid: hirsutism, striae, obesity, muscle weakness
-Cardiovascular: Fluid retention, hypertension
-Endocrine: DM
-MSK: proximal myopathy, AVN, osteoporosis
