Endocarditis, Myocarditis and Pericarditis Flashcards
What is bacteraemia?
The presence of viable bacteria in the blood stream
What is the old name for bacteraemia?
Septicaemia
What is endocarditis?
The endovascular inflammation of cardiovascular structures, usually involving the cardiac valves
What is myocarditis?
An inflammatory process leading to acute, subacute or chronic injury to the myocardium
What is pericarditis?
Inflammation of the pericardium
What are some forms of testing that can be carried out on blood cultures?
Haemolysis
Coagulase testing
Gram staining
MALDI-TOF
What is the main coagulase positive bacteria?
Staphylococcus aureus
What is the minimum number of blood cultures required in endocarditis?
3, as the more blood that is taken, the higher the sensitivity
What are some bacteria that will NOT grow on agar?
Bartonella sp
Coxiella burnetti
Chlamydia sp
Legionella sp
Mycoplasma sp
Brucella sp
What is another name for Coxiella burnetti infection?
Q fever
Where is someone most likely to contract Coxiella burnetti?
During the birthing of livestock
Where is someone most likely to contract Brucella?
From goats
What is the mnemonic for slow growing bacteria?
HACEK
What are the HACEK bacteria?
H - Haemophilus sp
A - Aggregatibacter sp
C - Cardiobacterium sp
E - Eikenella sp
K - Kingella sp
What are some common bacteria that infect wound sites and implantable devices?
Staphylococcus epidermidis
Staphylococcus aureus
Corynebacterium sp
Proprionibacterium sp
How long after the removal of an ICED should blood cultures be taken?
48 - 72 hours
What can form on the heart valves as a result of infective endocarditis?
Vegetations
How does infective endocarditis increase the risk of stroke?
Vegetations are friable and so can form septic emboli which can pass into the carotid arteries
Describe the pathogenesis of endocarditis?
Damage to a heart valve due to hypertension or turbulent blood causes formation of platelet and fibrin rich clots on the endocardium
Bacteraemia can then allow for the deposition of bacteria in the clot, forming a vegetation
What are some common causes of damage to the heart valves, therefore increasing the risk of endocarditis?
Calcification
Congenital conditions
Rheumatic fever
What are some risk factors for infective endocarditis?
Heart valve damage
Prosthetic heart valves
IV drug users
Dental damage or work
Intravascular lines
What are the most common organisms in infective endocarditis?
Staphylococcus aureus
Streptococcus viridans group
Enterococcus sp
Staphylococcus epidermidis
What effect will staphylococcus aureus have on blood agar?
It will cause a gold ring to form
What are some common examples of Viridans group streptococci?
Strep. mitis
Strep. sanguinis
Strep. mutans
Strep. salivarius
How are Viridans group streptococci likely to enter the blood stream
They are oral commensal bacteria so enter due to poor oral hygiene, during dental procedures or in IV drug users who lick the needle tip
What is the most common bacteria that infects those with prosthetic heart valves?
Staphylococcus epidermidis
What are the most common bacteria that infects those who inject drugs?
Candida
Staphylococcus aureus
What is the most commonly affected region in people who inject drugs?
The right side of the heart, most commonly the tricuspid valve
How are non-growing bacteria tested for in infective endocarditis?
Serology, which tests for the presence of antibodies
What are some tests that may be required in the diagnosis of infective endocarditis?
≥ 3 blood cultures
Echocardiography
Serology
What criteria is used for the diagnosis of infective endocarditis?
Modified Duke criteria
How many points are there in the modified Duke criteria?
7: 2 major (BE) and 5 minor (TIMER)
What are the points of the modified Duke criteria?
B - Blood cultures positive for major bacteria
E - Echocardiography shows vegetation
T - Temperature high (Fever)
I - Immunological signs
M - Microbiology suggestive of minor bacteria
E - Embolic phenomenon
R - Risk factors
What is meant by a positive blood result for major bacteria in the Duke criteria?
2 or more positive cultures for one of the following bacteria:
- Streptococcus viridans
- Streptococcus gallolyticus
- HACEK group bacteria
- Staphylococcus aureus
- Enterococcus sp
What other test should be performed in a positive result of Streptococcus gallolyticus?
Colonoscopy due to its association with bowel cancer
What are some immunological signs of infective endocarditis?
Roth spots
Osler nodes
What are some examples of embolic phenomena in infective endocarditis?
Septic emboli
Janeway lesions
What are the 2 ways in which infective endocarditis can present?
Acute presentation
Sub-acute presentation
What are some clinical symptoms of acute infective endocarditis?
Overwhelming sepsis
Cardiac failure
What are some clinical symptoms of sub-acute infective endocarditis?
Slow onset
Fever
Malaise
Weight loss
Tiredness
Dyspnoea
What are some clinical signs of sub-acute infective endocarditis?
New or changing murmur
Finger clubbing
Splinter haemorrhage
Splenomegaly
Roth spots
Janeway lesions
Oslers nodes
Microscopic haematuria
What are Roth spots?
Non-specific red spots, seen on the retinae
What are Janeway lesions?
Non-tender, small, flat erythematous haemorrhagic lesions on the palm or sole, caused by septic emboli
What are Osler nodes?
Painful, red, raised lesions found on the palms or soles, caused by immune complex deposition
What is the most common cause of acute infective endocarditis?
Staphylococcus aureus
What is the empirical treatment for native valve acute infective endocarditis?
Flucloxacillin IV
What is the empirical treatment for native valve sub-acute infective endocarditis?
Amoxicillin + Gentamicin IV
What is the empirical treatment for prosthetic valve infective endocarditis?
Vancomycin + Gentamicin IV + Rifampicin PO on days 3-5
What is the empirical treatment for infective endocarditis in those who inject drugs?
Flucloxicicllin IV (Treated as Staph aureus)
What is the empirical treatment for infective endocarditis with suspected MRSA?
Vancomycin + Gentamicin IV + Rifampicin PO (Days 3-5)
What is the culture specific treatment for Staphylococcus aureus (Non-MRSA) in infective endocarditis?
Flucloxicillin IV
What is the culture specific treatment for Viridans group Streptococci in infective endocarditis?
Benzylpenicillin + Gentamicin IV
What is the culture specific treatment for Staphylococcus epidermidis in infective endocarditis?
Vancomycin + Gentamicin IV + Rifampicin PO (Days 3-5)
What is the culture specific treatment for Enterococcus sp in infective endocarditis?
Amoxicillin/Vancomycin + Gentamicin IV
What are the 2 main forms of Non-infective endocarditis?
Non-bacterial thrombotic endocarditis
Libmen-Sacks endocarditis
What is non-bacterial thrombotic endocarditis?
This is the formation of multiple small, sterile vegetations, which do not destroy valves and are caused by hyper coagulable states such as in pregnancy or cancer
What is the main risk of non-bacterial thrombotic endocarditis?
The thrombi can cause embolic diseases if the break apart
What is Libmen-Sacks endocarditis?
This is a form of endocarditis thought to be caused by deposition of immune complexes, resulting in small, sterile thrombus formation on both sides of the valve
What disease is thought to be the main cause of Libmen-Sacks endocarditis?
Systemic Lupus Erythematosus (SLE)
What is the most common viral cause of myocarditis in Europe and Northern America
Coxsackievirus
What is the most common viral cause of myocarditis globally?
Diphtheria
What is the most common viral cause of myocarditis in Southern America?
Chaga’s disease due to trypanosomiasis
What are some other common viral causes of myocarditis in the UK?
Lyme’s disease due to Borrelia burgdorferi
ECHO viruses
What are some non-infectious causes of myocarditis?
Hypersensitivity in rheumatic fever
Eosinophilic myocarditis (Hypersensitivity to drugs)
Systemic Lupus Erythematosus (SLE)
What structures are commonly formed by non-infectious forms of myocarditis?
Aschoff bodies
What are Aschoff bodies?
These are rheumatic granulomas, formed by macrophages such as Aschoff cells and Anitchkov cells, which surround collagen fibres and a central collagen necrosis
What are some possible symptoms of myocarditis?
Fever
Chest pain
Dyspnoea
Palpitations
What are some possible clinical signs of myocarditis?
Soft heart sounds
Prominent 3rd heart sound
Tachycardia
Cardiac failure
What are some tests that can be carried out in myocarditis?
ECG
Blood testing
CXR
Viral PCR
Autoantibodies
Endomyocardial biopsy (Risky)
Cardiac MRI
What are some diagnostic changes on ECG that may be present in myocarditis?
ST elevation or depression
T wave inversion
Atrial arrhythmia
Transient AV block
What are some blood test findings that can show myocarditis?
Raised troponin
Raised creatinine
Raised inflammatory markers
What is the use of cardiac MRI in myocarditis?
It can be used to differentiate between acute myocarditis and infarction
What is the main viral aetiology of pericarditis?
ECHO virus
What type of effusion will be present in echovirus caused pericarditis?
This will produce serous effusions (Apple juice)
What type of effusion will be present in a bacterial pericarditis?
Purulent effusions
What type of effusion will be present in a fungal pericarditis?
Purulent effusions
What type of effusion will be present in a pericarditis caused by tuberculosis?
Caseous (Cheesy) effusion
Who is most at risk of fungal pericarditis?
Those who are immunosuppressed
What is Dressler’s syndrome?
Pericarditis that occurs 4-6 weeks post MI
What causes Dressler’s syndrome?
Damaged heart muscle releases previously unencountered material, therefore mounting an immune response against it
What are some non-infective causes of pericarditis?
Rheumatic fever
Dressler’s syndrome
Uraemia in renal failure
Connective tissue disorders (e.g. SLE)
What is a common symptom of pericarditis?
Pleuritic chest pain which is worse on inspiration and is relieved by sitting up
What are some clinical signs of pericarditis?
Low grade fever
Pericardial friction rub
What are some diagnostic ECG changes in pericarditis?
Saddle shaped ST elevation
PR interval depression
What is the usual management option in pericarditis?
Treatment is usually supportive to manage main, such as NSAIDS
What are some possible complications of pericarditis?
Pericardial effusion
Tamponade
Constrictive pericarditis
Cardiac failure
Death
