5: Infective endocarditis and other cardiac infections Flashcards
Blood is normally ___.
sterile
What is the name given to the presence of bacteria in the bloodstream?
Bacteraemia / septicaemia
If septicaemia is left untreated, the patient can go into ___ ___ and die.
septic shock
Before an appropriate antimicrobial treatment is prescribed, you need to take __ __ to figure out what organism you need to target.
blood cultures
What is infective endocarditis?
Infection of the endothelium of the heart valves
Infective endocarditis causes ___ blood flow which promotes the growth of microbes into big lumps.
turbulent
Infective endocarditis can be either ___ or _-___.
acute , subacute
What are predisposing factors for infective endocarditis?
Heart valve abnormalities - calcification, sclerosis, congenital heart disease and rheumatic fever
Prosthetic heart valves
IV drug users
IV lines
___ and ___ are deposited on heart valves with areas of turbulent blood flow.
Platelets , fibrin
i.e a thrombus forms
What settles in fibrin/platelet thrombi in the heart valves?
Bacteria
Microbes released by ___ treatment can be involved in infective endocarditis.
dental
Infected “vegetations” are friable - what does this mean?
Unstable, likely to break off
Infected vegetations break off and lodge in __ ___, where they can cause abscess or haemorrhage.
capillary beds
Which side of the heart, and which valves, are more commonly affected by endocarditis?
Left side
(mitral, aortic valves)
What is the most common organism causing endocarditis?
Staphylococcus aureus
What are the four most common organisms which cause endocarditis?
Staphylococcus aureus
Streptococcus virdians
Entercoccus spp,
Staphylococcus epidermidis
What are some atypical organisms which cause endocarditis?
Bartonella
Coxiella burnetti (Q-fever)
Chlamydia
Legionella
What are the major Duke criteria for diagnosing endocarditis?
Two separate positive blood cultures for typical organisms (to prove it’s PERSISTENT)
Echocardiogram evidence of valve lesions
New valvular regurgitation
When diagnosing endocarditis, at a minimum, how many positive blood cultures do you need?
2
How do you obtain evidence of valvular lesions to diagnose endocarditis?
Echocardiogram
What kind of valve disease indicates endocarditis?
Regurgitation
Which two echos are done to diagnose endocarditis?
Transthoracic echo
then
Transoesophageal echo to make sure
What kind of microbe is Staph. aureus?
Gram +ve cocci
How do staphylococci appear?
Big round clumps
If you find Staph. epidermidis after doing a blood culture, chances are it is there as a result of…
contamination
i.e not responsible for the endocarditis - it might be tho
In which case should the appearance of Staph. epidermidis be taken more seriously than normal?
If it is persistently appearing and the patient has a lot of prosthetic material
Coagulase positive Staphylococcus are ___ ___.
A coagulase negative Staphylococcus is ___ ___.
Staph. aureus
Staph. epidermidis
What new tool allows microbiologists to better identify organisms?
MALDI-TOF
The most dangerous gram positive organism, causing high mortality endocarditis, is…
Staph. aureus
How do patients present with acute endocarditis?
Sepsis
Cardiac failure
What are the symptoms of subacute endocarditis?
Fever
Malaise
Weight loss
Fatigue
Breathlessness
What are the signs of subacute endocarditis?
Fever
Cardiac murmurs
Finger clubbing
Splinter haemorrhages
Roth spots
Osler nodes
Janeway lesions
Which group of microorganisms tend to cause subacute endocarditis?
Viridans group of Streptococci
What is the difference between Osler’s nodes and Janeway lesions?
Osler’s nodes are painful (Osler = ouch)
Janeway lesions aren’t painful
How many blood cultures should you take to confirm persistent bacteraemia?
3 sets
Why are transthoracic echos easier to perform than transoesophageal echos?
No fasting required
Can be done at the bedside
A typical echo finding of endocarditis is valve…
mobility - i.e it moves a ton, is loose
People with ___ valves are more likely to get endocarditis.
prosthetic
Rifampicin tends to be used when the bacterial volume has been reduced as bacteria tend to become ___ to it.
resistant
People who inject ___ are more likely to develop endocarditis.
drugs
Which kind of endocarditis tends to start on the right side of the heart?
Endocarditis in people who inject drugs
Which microbe causes endocarditis in people who inject drugs?
Staphylococcus aureus
What can occur as a result of right heart blood stasis in the endocarditis of PWID?
Pulmonary emboli
How long are IV antibiotics given for infective endocarditis?
4-6 weeks
The prognosis of endocarditis very much depends on other patient ___.
factors
In general, prophylaxis for endocarditis gives (a great benefit / absolutely no benefit).
absolutely no benefit
Not done anymore.
What kind of heart inflammation is more common in young people?
Myocarditis
What are some symptoms of myocarditis?
Fever
Chest pain
Breathlessness
Palpitations
What are some signs of myocarditis?
Arrythmia
Cardiac failure
What kind of microbes tend to cause infective myocarditis?
Viruses
Which three types of viruses are responsible for most myocarditis?
Enteroviruses (coxsackieviruses)
Adenoviruses
Influenza
What is the treatment for viral myocarditis?
Rest
Analgesia
Most viral myocarditis resolves normally.
However, if there is an autoimmune reaction, what kind of cardiomyopathy can result?
Dilated cardiomyopathy
which can cause sudden death due to heart failure.
What is pericarditis?
Inflammation of the pericardium
Which two inflammatory heart diseases tend to occur together?
Myocarditis and pericarditis
What is the main symptom of pericarditis?
Chest pain
Which viruses tend to cause pericarditis?
Viruses - coxsackieviruses, adenoviruses, influenza
If pericarditis occurs as a result of ___, it is treated much more seriously.
tuberculosis
What is the treatment for pericarditis?
Bed rest
Analgesia
What surgical intervention is performed for severe endocarditis?
Valve replacement
