Endocarditis Creator: Cameron McCloskey Flashcards
Normally, blood is ________
Sterile
What is bacteraemia?
The presence of bacteria in the blood
What is septicaemia?
The presence and multiplication of bacteria in the blood
What is infective endocarditis?
Infection of the heart valve endothelium
This cause valve irregularities which leads to turbulent blood flow
Valve irregularities may break free and pass into the blood
What are the risk factors for infective endocarditis?
- Any heart valve abnormality - calcification/sclerosis, congenital, post rhematic fever
- Prosthetic heart valaves
- IV drug users
- Intravascular lines
How does endocarditis come about?
There is damage to the heart valve causing turbulent blood flow
This causes deposition of platelets and fibrin
In infcetive endocarditis, microbial vegetations can settle within the platelet/fibrin thrombi
These can break off and form blockages in capillary beds
Bacteraemia can come about after ________ treatment
Dental
Which side of the heart is most often affected by endocarditis?
Left side
Which organisms are most likely to cause infective endocarditis?
- Staph aureus (38%)
- Step viridans (31%)
- Enterococcus sp (8%)
- Staph epidermidis (6%)
What are some more unusual examples of organisms that can cause endoarditis?
- Atypical organisms
- Bartonella, Coxiella burnetii (Q-fever), Chlamydia, Legionella, Mycoplasma, Brucella
- Gram-negatives
- HACEK organisms
- Haemophilus spp. , Aggregatibacter spp**, Cardiobacterium, Eikenella sp., Kingella sp.
- Non-HACEK gram negatives
- HACEK organisms
- Fungi
Why are atypical organisms hard to diagnose as the cause of endocarditis?
They are hard to culture, and are slow to grow
How often should blood cultures be taken during treatment of endocarditis?
Every 2-3 days until the results are negative
How is endocarditis diagnosed?
- Firstly a transoesophageal echo is taken
- The result (positive or negative) from this is confirmed by the more accurate transthoracic echo
What is the coagulase test?
Coagulase is an enzyme produced by S.aureus which converts soluble fibrinogen to insoluble fibrin
If fibrin is produced in this test S.aureus is present, and if it is not another form of staphylococcus is present
What is the most common coagulase negative test result for?
Staphylococcus epidermidis
Where is S.epidermidis likely to come from?
It can infect metal and plastic (prosthetic material) such as IV lines, prosthetic heart valves and joints.
What is MALDI TOF?
A machine that can identify the species of microorganism and most relevant treatment
How does acute endocarditis present clinically?
Cardiac failure and overwhelming sepsis
There is poor organ functiondue to lower blood pressure
Aggressive and virulent pathogens such as S.aureus cause this
How does subacute endocarditis differ from acute endocarditis?
It has a slower onset
Whaat are typical symptoms of subacute endocarditis?
- Fever
- Malaise
- Weight loss
- Tiredness
- Breathlessness
What are typical signs of subacute endocarditis?
- Fever
- New or changing heart murmur
- Finger clubbing
- Splinter haemorrhages
- Splenomegaly
- Roth spots, Janeway lesions, Osler’s nodes
- Microscopic haematuria
Subacute endocarditis is often cause by which bacterial group?
Streptococcus viridans
Generally the Strep viridans group will be _____ haemolytic
Alpha
When diagnosing endocarditis, how many blood cultures should be taken?
3
(this rules out contaminents easier)
When blood cultures are negative, which other test may find more unusual or atypical organisms?
Serology
Prosthetic valve endocarditis can have both early and late presentations, differentiate between the likely causes of the two
Early - Infected at the time of valve insertion - usually S.aureus or S.epidermidis
Late - Infected many years after valve insertion due to coincidental bacteraemia, this can be due to many bacteria
Why is the right side of the heart most affected by endocarditis in IV drug users?
The venous system is used for IV drug use, so bacteria will arrive firstly at the right side of the heart
Which heart valve is most likely affected by endocarditis in IV drug users?
Tricuspid
When S.aureus affects the tricuspid valve in an IV drug user causing endocarditis, what is a serious condition that may result?
Multiple septic pulmonary emboli released
How is endocarditis treated if the native valve is infected?
Amoxicillin and gentamicin IV
How is endocarditis treated if a prosthetic valve is infected?
- Vancomycin and gentamicin (IV)
- Rifampicin (after 3-5 days, more effective at lower bacterial load)
- Potential valve replacement
How is IV drug users’ endocarditis treated?
Flucloxacillin IV
How is S.aureus treated in relation to endocarditis?
Flucloxacillin IV
How is viridans streptococci treated in relation to endocarditis?
Benzylpenicillin IV and gentamicin IV
How is S.epidermidis treated in relation to endocarditis?
Vancomycin and gentamicin IV and rifampicin
What must be monitored during antibiotic treatment for endocarditis?
- Cardiac function
- Temperature
- Serum C-reactive protein
Which organs will endocarditis primarily affect?
- Brain
- Kidneys
- Spleen
Lungs are only effected rarely or with IV drug users
What is marantic endocarditis?
This is nonbacterial thrombotic endocarditis which is an autoimmune disease
Vegetations on the heart are sterile
What is myocarditis?
Condition common in young people involving inflammation and damage to the heart muscle
What are symptoms of myocarditis?
- Fever
- Chest pain
- Breathessness
- Palpitations
What are signs of myocarditis?
- Arrhythmia
- Cardiac failure
Which pathogens can cause myocarditis?
- Coxsackie A and B
- Echovirus
- Influenza
- Adenovirus
How is myocarditis diagnosed?
- Viral PCR
- Throat swab (check for influenza)
- Stool (check for enteroviruses)
What can often happen when an immune reaction is provoked in myocarditis?
An autoimune condition will result and dilated cardiomyopathy will result
This will lead to arrhythmias and sudden death
What is pericarditis?
Inflammation of the pericardium
Pericarditis can often occur alongside what ther condition?
Myocarditis
What is usually the cause for pericarditis?
Viral causes such as:
- Coxsackie
- Adenoviruses
- Influenza
- Pneumococcus
What is the main symptom of pericarditis?
Chest pain
What can happen in pericarditis when bacteria are the cause?
Pus can build up in the pericardial space which is as a result of post cardiac surgery.
What is the clinical features of MI
present acutely and progress rapidly with heart failure symptoms or present chronically
most common sign of IE
Fever
PR interval prolongation in a patient with Infective Endocarditis is an indication for surgery True/ FALSE
TRUE
PR prolongation or complete AV block - sign of aortic root abscess
what is the first line of imaging investigation and what is the most sensitive for IE
- Transthoracic echocardiogram is the first line imaging investigation
- Transoesophageal echocardiogram
A 62-year-old male with a prosthetic valve and whose blood culture results have not yet returned
Vancomycin IV + gentamicin IV + rifampicin PO
Random tip: native valves are the OG (original) valves give amoxicillin and gentamicin, prosthetic valves are very good new valves give vancomycin and gentamicin (and rifampicin)
A 25-year-old female who is a known IV drug user and whose blood culture results have not yet returned
Flucloxacillin IV
A 47-year-old male with a history of rheumatic fever whose blood culture results have not yet returned
Amoxicillin IV + gentamicin IV
A 47-year-old male with a history of rheumatic fever whose blood culture results are positive for Viridians group streptococci
Benzylpenicillin IV + gentamicin IV