(3) Cardiovascular diseases 3 Flashcards
What is endocarditis?
Inflammation of the endocardium of the heart (thin, smooth membrane which lines the inside of the chambers of the heart and forms the surface of the valves)
What is the prototypical lesion in endocarditis?
Vegetations on the valves
What are the 2 main forms of endocarditis?
- infective endocarditis (clinically important)
- non-infective endocarditis
Name 2 types of non-infective endocarditis
- nonbacterial thrombotic endocarditis (NBTE)
- endocarditis of SLE (Libman-Sacks Disease)
What is infective endocarditis?
Colonisation/invasion of heart valves or heart chamber endocardium by a microbe - clinically serious infection
Describe the vegetations in infective endocarditis
- mixture of thrombotic debris and organisms
- destroy underlying cardiac tissue
- aorta, aneurysmal sacs, blood vessels, prosthetic valves can also be infected
What causes infective endocarditis?
Most cases are caused by bacterial infection
Fungi/other classes can also cause IE
Name 2 classifications of infective endocarditis
- acute infective endocarditis
- sub-acute infective endocarditis
Which type of infective endocarditis is the worst? (acute or sub-acute)
Acute infective endocarditis
What type of organism causes acute infective endocarditis vs. sub-acute infective endocarditis?
actue infective endocarditis = highly virulent organisms
sub-acute infective endocarditis = organisms of lower virulence
What type of lesions are there in acute infective endocarditis vs. sub-acute infective endocarditis?
acute infective endocarditis = necrotising, ulcerative, destructive lesions
sub-acute infective endocarditis = less destructive
How are acute infective endocarditis and sub-acute infective endocarditis cured?
acute infective endocarditis = difficult to cure with antibiotics and usually require surgery
sub-acute infective endocarditis = cured with antibiotics
What are the main features of acute infective endocarditis? (nasty)
- can occur with infection of a previously normal heart valve
- caused by highly virulent organisms
- necrotising, ulcerative, destructive lesions
- difficult to cure with antibiotics and usually require surgery
- death frequent days to weeks despite treatment
What are the main features of sub-acute infective endocarditis? (less nasty than acute)
- organisms of lower virulence
- insidious infections of deformed valves
- less destructive
- protracted “wax and wane” course of weeks to months
- cured with antibiotics
Infective endocarditis can occur in normal hearts but what are the risk factors?
- cardiac/valvular abnormalities
What used to be a major cause/risk factor of infective endocarditis?
Rheumatic heart disease
Cardiac/valvular abnormalities are risk factors for infective endocarditis. Give examples
- MV prolapse
- valvular stenosis
- artificial valves
- unprepared and repaired congenital defects
- bicuspid AV
How does an infection get into the heart?
Any route of bacteria into the blood stream eg.
- dental abnormalities
- IVDU
- wounds
- bowel cancer
Give 3 examples of bacteria that cause infection in the heart
- streptococcus viridans
- S. aureus
- coagulase-negative staphylococci
Which is the most common bacterial cause of infective endocarditis?
Streptococcus viridans (50-60% of cases)
Streptococcus viridans can cause infective endocarditis. Where does it come from and what does it infect?
- from the mouth
- causes endocarditis in native but damaged/abnormal valves
What proportion of infective endocarditis cases are caused by S. aureus?
10-20% of cases overall, especially in IVDU
S. aureus can cause infective endocarditis. Where does it come from?
The skin
causes cases when there is IVDU
Give an example of a coagulase-negtive staphylococci (can cause infective endocarditis)
S. epidermidis
Coagulae-negative staphylococci can cause infective endocarditis. What does it commonly infect?
Prosthetic heart valves
What should infective endocarditis caused by Strep. bovis prompt?
Investigation for bowel cancer
What makes up 10-15% of cases of infective endocarditis?
Culture negative endocarditis
What is culture negative endocarditis? (10-15% of cases)
No endocarditis-causing bacteria can be found on a blood culture eg. because the certain bacteria do not grow well on culture
Describe the vegetations in acute infective endocarditis
- friable, bulky and potentially destructive
- single, multiple and often more than one valve
Where do you get vegetations in acute infective endocarditis?
- aortic valve
- mitral valve
- right heart ( especially in IVDUs)
What can occur with vegetations in acute IE?
Can erode into the myocardium and cause ring abscesses
What happens when bits of the vegetations break off? (in acute IE)
Can cause septic emboli which contain large number of virulent organisms
- get abscesses at sites where the emboli lodge in distant vessels
- this can cause septic infarcts or mycotic aneurysms
What is the difference in the vegetations in sub-acute IE compared to acute IE?
Less destruction
State the clinical features of infective endocarditis
- fever
- non-specific symptoms
- murmurs
Fever is a clinical sign of infective endocarditis. Explain in more detail
- most consistent sign
- rapidly developing fever, chills, weakness
- can be slight or absent, particularly in the elderly
In infective endocarditis, there are non-specific signs as well as fever and murmurs etc. Give examples
- weight loss
- flu-like syndrome
Murmurs are a clinical sign in infective endocarditis. Give more detail
- 90% of patients with left-sided IE
- new valvular defect or represent a pre-existing abnormality
Give an example of complications associated with infective endocarditis
- immunologically mediated conditions eg. glomerulonephritis
What are the clinical manifestations of infective endocarditis? (micro-thromboemboli)
- splinter/subungual haemorrhages
- Janeway lesions
- Osler’s nodes
- Roth spots
Janeway lesions are a clinical manifestation of infective endocarditis. What are they?
Erythematous or haemorrhagic non-tender lesions on the palms or soles
Osler’s nodes are a clinical manifestation of infective endocarditis. What are they?
Subcutaneous nodules in the pulp of the digits
Roth spots are a clinical manifestation of infective endocarditis. What are they?
Retinal haemorrhages in the eyes
How can you remember the clinic signs/manifestations of infective endocarditis?
FROM JANE
F - fever
R - Roth spots
O - Osler’s nodes
M - murmurs
J - Janeway lesions
A - anaemia
N - nail (splinter) haemorrhages
E - emboli (septic)
What is non-bacterial thrombotic endocarditis (NBTE) also known as?
Marantic endocarditis
Who does non-bacterial thrombotic endocarditis occur in?
Debilitated patients eg. cancer or sepsis
Those who are chronically ill
What is non-bacterial thrombotic endocarditis associated with?
Hypercoagulable state
(hence DVT, PE, and mutinous adenocarcinomas)
(pro-coaguant effects of tumour-derived mucin or tissue factor)
Non-bacterial thrombotic endocarditis (NBTE) is a part of what?
Trousseau syndrome of migratory thrombophlebitis
What is the Trousseau syndrome of malignancy? (NBTE is part of it)
Medical sign involving episodes of vessel inflammation due to blood clot (thrombophlebitis) which are recurrent or appearing in different locations over time (migratory thrombophlebitis).
What predisposes you to non-bacterial thrombotic endocarditis (NBTE)?
- endocardial trauma/indwelling catheter eg. central line
Describe the vegetations in non-bacterial thrombotic endocarditis (NBTE)
- small (1-5mm) sterile thrombi on valve leaflets
- single or multiple on line of closure of leaflets or crisps
- not invasive/no inflammatory reaction = minimal local effect
- systemic emboli (infarcts into the brain, heart etc)
Another type of non-infective endocarditis is Libman-Sacks endocarditis. What is it associated with?
Systemic lupus erythematosis (SLE)
What are the symptoms of Libman-Sacks endocarditis?
- usually asymptomatic (other than features of SLE)
- rarely cardiac failure or systemic emboli
Which valves are affected in Libman-Sacks endocarditis?
- mitral valve
- tricuspid valve
Describe the vegetations in Libman-Sacks endocarditis?
- small (1-4mm) sterile pink warty vegetations
- single or multiple
- AV valves (often under-surfaces), on the chordae, valvular endocardium or mural endocardium of atria or ventricles
What is rheumatic fever?
Acute, immunologically-mediated, multi-system inflammatory disease following group A streptococcal pharyngitis
Why is rheumatic fever now rare?
Because of improved diagnosis/treatment
- 15 million in developing countries/poor Western populations
What are Aschoff bodies?
- distinctive cardiac lesions in rheumatic fever
- foci of T cells, plasma cells and macrophages
- can be found in all 3 cardiac layers
What are the vegetations called in rheumatic fever?
Veruccae
Changes to which valve are classical in rheumatic fever?
Mitral valve changes
What is the virtually the only cause of mitral stenosis?
Rheumatic fever
What kind of mitral valve changes do you get in rheumatic fever?
Leaflet thickening
In rheumatic fever you get mitral valve changes only is most cases (virtually always involved in chronic disease). What other valve may be affected?
Aortic valve in 25% of cases
Tricuspid valve and pulmonary valves - uncommon
What kind of mitral stenosis do you get in rheumatic fever?
Fibrous bridging of valvular commissures and calcification
“fish mouth” or “buttonhole” stenoses
Describe the aetiology of rheumatic fever
- hypersensitivity reactions (combined antibody and T-cell mediated response
- immune responses to group A strep (pharyngitis)
Explain how the immune response to group A strep causes rheumatic heart disease
- antibodies directed against the M proteins of streptococci = cross-react with self antigens in the heart
- CD4+ T cells specific for streptococcal peptides = react with self proteins in the heart, produce cytokines that activate macrophages eg. Aschoff bodies
Which criteria is used for diagnosis of rheumatic heart disease?
Jones criteria
What is the required criteria in Jones criteria for diagnosis of rheumatic fever?
Evidence of streptococcal infection
What is the major diagnostic criteria in Jones criteria for diagnosis of rheumatic fever?
- carditis
- polyarthritis
- chorea
- erythema marginatum
- subcutaneous nodules
What is the major diagnostic criteria in Jones criteria for diagnosis of rheumatic fever?
- fever
- arthralgia
- previous RHD
- acute phase reactions (ESR/CRP/leukocytosis)
- prolonged PR interval
How is diagnosis made in Jones criteria?
- 1 required criteria + 2 major criteria + 0 minor criteria
OR - 1 required criteria + 1 major criteria + 2 minor criteria
What is pericarditis?
Inflammation of the pericardial sac
What are the 3 main causes of pericarditis?
- infections
- immunologically mediated processes
- miscellaneous conditions
Give examples of infections that can cause pericarditis
- viruses (coxsackie B)
- bacteria
- TB
- fungi
- parasites
Give examples of immunologically mediated processes that can cause pericarditis
- rheumatic fever
- SLE
- scleroderma
- post-cardiotomy
- late post-MI (Dressler’s)
- drug hypersensitivity
What is Dressler’s syndrome?
Form of pericarditis that occurs in injury to the heart or pericardium
Also known as postmyocardial infarction syndrome
Believed to be an immune system response after damage to heart tissue or to the pericardium, from events such as a heart attack
Give examples of miscellaneous conditions that can cause pericarditis
- post-MI (early)
- uraemia
- cardiac surgery
- neoplasia
- trauma
- radiation
What are the 2 main different forms of pericarditis?
- acute pericarditis (inflamed)
- chronic pericarditis (stuck down)
What are the different forms of acute pericarditis?
- serous
- serofibrinous/fibrinous
- purulent/suppurative
- haemorrhagic
- caseous