PATHOLOGY- Heart disorders 2 Flashcards
What is acute rheumatic fever?
Acute immunologically mediated multi system inflammatory disease following group A beta haemolytic streptococcal infection
What is rheumatic heart disease
VALVULAR disease resulting from chronic valve damage as a result of acute rheumatic fever (AKA rheumatic valve disease)
What is the difference acute rheumatic fever and rheumatic heart disease?
acute rheumatic fever is inflammatory disease whereas rheumatic heart disease is a valvular disease
What causes acute rheumatic fever?
An immunologically mediated inflammatory disease usually following group A streptococcal pharyngitis
In which groups of people is acute rheumatic fever common in?
Commonly in children between the ages of 5-15
What is acute rheumatic fever characterised by?
Delayed, chronic inflammatory changed in primarily the heart, blood vessels, joints subcutaneous tissue and CNS
When do symptoms and signs of acute rheumatic fever start showing?
10 days to 6 weeks post infection
What type of reaction does acute rheumatic fever cause?
A hypersensitivity reaction
a combined antibody and T cell response
To what pathogen is the immune response targeting in a patient with acute rheumatic fever?
group A strep (pharyngitis)
How can the immune response fighting acute rheumatic fever harm the host?
- Antibodies that are directed against the M proteins of streptococci end up cross reacting with self antigens in the heart
- CD4+ T cells specific for streptococcal peptides react with self proteins in the heart
- CD4+ T cells produce cytokines that activate macrophages
Immunological damage in patients with acute rheumatic fever can affect…
- Joints
- Subcutaneous tissues
- Basal ganglia of the brain
- Heart valves/ heart tissue
What is acute rheumatic fever in the heart called?
Acute rheumatic carditis
Carditis of the pericardium is called what?
Pericarditis
Carditis of the Myocardium is called what?
Myocarditis (aschoff body)
Carditis of the Endocardium is called what?
Valvulitis
What is another name for myocarditis?
Aschoff body
What is chronic valve damage due to acute rheumatic fever called?
Rheumatic heart (valve) disease
Do pericarditis or myocarditis lead to chronic disease?
No they are only vascular manifestations
What is Aschoff body
A sign of myocarditis
Describe the histology of Aschoff body
- Distinctive cardiac lesions can be seen
- Foci of T cells, plasma cells and macrophages can be seen (anitschkow cells)
Where can Aschoff body be found?
In all three cardiac layers (known as pancarditis)
What is acute rheumatic fever characterised by?
Its systemic symptoms and signs
List some of the systemic signs and symptoms of acute rheumatic fever
- Migratory polyarthritis of the large joints
- Pancarditis
- Subcutaneous nodules
- Skin lesions
- Sydenham chorea
What is Sydenham chorea?
Involuntary purposeless movements
Name the criteria we use to diagnose acute rheumatic fever ?
Jones criteria
Describe jones criteria
Jones criteria requires evidence of a preceding group of A streptococcal infection
Alongside either:
2 major manifestations
OR
1 major and 2 minor manifestations
What does pancardititis refer to?
Inflammation across all three layers of the heart
Name the 3 cardiac layers
- Pericardium
- Myocardium
- Endocardium
What is the first thing you need to identify when using Jones criteria
Evidence of preceding GROUP A STREPTOCOCCAL infection
List the major diagnostic criteria (using jones criteria) to diagnose acute rheumatic fever
- Carditis
- Polyarthritis
- Chorea
- Erythema marginatum
- Subcutaneous nodules
List the minor diagnostic criteria (using jones criteria) to diagnose acute rheumatic fever
- Fever
- Arthralgia
- Previous rheumatic heart disease or fever
- Acute phase reactions
- Prolonged PR intervals
Why does it take 10 days - 6 weeks for clinical features to become apparent in patients with acute rheumatic fever?
As it takes time to accumulate an immune response
Name the main manifestations of acute rheumatic fever
- Acute (pan)carditis
- Migratory Polyarthritis
What is migratory polyarthritis
When one large joint after another becomes painful and swollen for a period of days and then subsides spontaneously leaving no residual disability
What is acute pancarditis
Pericaridal friction rubs, tachycardia and arrhythmias
What can myocarditis cause
Myocarditis can cause cardiac dilation that may culminate in function mitral valve insufficiency or even heart failure
Which part of the heart is affected by rheumatic heart disease
Valves are damaged in a cumulative and permanent manner
What can patients with rheumatic heart disease develop?
Can develop:
- Cardiac hypertrophy
- Dilation
- Heart failure
- Arrhythmias
Give some complications associated with rheumatic heart disease
- Thromboembolic complications due to atrial dilation/ fibrillation
- Infective endocarditis
How can we treat rheumatic heart disease
Can try and surgically repair or carry out a prosthetic replacement of the diseased valves
Describe the pathology of rheumatic heart disease
- Veruccae form in the heart
- Mitral valve changes
- Fibrous bridging of valvular commissures and calcification
What are Veruccae?
Vegetations in the heart
What does we mean when we say Veruccae form in the valves
Nodules of fibrous tissue form in areas where the valves close
Why do Veruccae form
Due to the autoimmune response of self reacting T cells and antibodies occurring along the areas where the valves open and close
This autoimmune reaction results in a nodular fibrosis response in the long term
What can mitral valve changes cause?
Mitral stenosis
What is mitral stenosis?
Narrowing of the heart’s mitral valve
what is virtually the only cause of mitral stenosis
virtually the only cause of mitral stenosis is rheumatic heart disease as a result of acute rheumatic fever
What secondary problems can arise due to mitral stenosis?
- Right ventricular hypertrophy
- Atrial fibrillation
Name the main valve involved in chronic heart diseases
Mitral valve (aortic valve can be involved in up 25% of cases)
Where is the mitral valve located?
Between the left atrium and the left ventricle of the heart
what is a charcteristic lesion of mitral valve stenosis
Fibrous bridging of valvular commissures & calcification
What is another term for fibrous bridging of valvular commissaries?
Fish mouth or button hole stenoses
What is endocarditis
Inflammation of the endocardium of the heart
Name the prototypical lesion in endocarditis
Vegetation on the valves
Name the 2 main forms of endocarditis?
- Infective endocarditis
- Non infective endocarditis
What is infective endocarditis due to?
Colonisation/ invasion of heart valves or heart chamber endocardium by a microbe
Describe the vegetations you can see in a patient with infective endocarditis
It is a mixture of thrombotic debris and organisms that has destroyed underlying cardiac tissue
Alongside the endocardium what else can be infected in a patient with infective endocarditis?
- Aorta
- Aneurysmal sacs
- Blood vessels
- Prosthetic valves
What causes most cases of infective endocarditis
Bacterial infection
fungi/ other classes can also cause
Name the 2 subtypes of infective endocarditis
- Acute infective endocarditis
- Subacute infective endocarditis
When can acute infective endocarditis occur?
Can occur with infection of a previously normal heart valve
What is acute infective endocarditis caused by?
Highly virulent organisms
What is acute infective endocarditis characterised by?
Necrotising, ulcerative, destructive lesions that may perforate through the valve spontaneously
What can happen if a valve perforates
It is no longer competent in stopping the backflow of blood which can lead to death
How do we treat acute infective endocarditis
Difficult to treat with antibiotics and usually requires urgent surgery
death frequent days to weeks despite treatment
What is subacute infective endocarditis caused by?
An organism of lower virulence
Name virtually the only cause of mitral stenosis
Mitral valve changes due to rheumatic heart disease (which is caused by acute rheumatic fever)
How are the symptoms of subacute infective endocarditis described as?
Described as a protracted wax and wane course of symptoms that last over weeks to months
what does subacute infective endocarditis tend to occur in
previously deformed valves
How do we treat sub acute infective endocarditis?
Cured with antibiotics
List the 2 factors that contribute to the development of infective endocarditis
- Organism must be present in the blood stream to cause the infection
- Cardiac vascular abnormality needs to be present that results in abnormal blood flow promotion adherence and growth of infection
Can infective endocarditis occur in a normal heart
Yes
List some risk factors for infective endocarditis
- Cardiac/ valvular abnormalities leading to abnormal blood flow
- Rheumatic heart disease
- Mitral valve prolapse
- Valvular stenosis
- Artificial (prosthetic) valves
- Congenital defect (bicuspid AV)
What is a major cause of infective endocarditis
Rheumatic heart disease
Why is rheumatic heart disease a major cause of infective endocarditis
As it can lead to mitral stenosis which in turn leads to abnormal blood flow which can can promote adherence and growth of infection
Name the type of infective endocarditis intravenous drug users can develop
Polymicrobial infective endocarditis
What is polymicrobial infective endocarditis
It is an infection due to multiple different organisms
Who is most affected by polymicrobial infective endocarditis
Younger aged male patients
Which side of the heart is more affected by polymicrobial infective endocarditis
Right hand side involvement in more than 60%
polymicrobial infective endocarditis in which side of the heart is more deadly?
Mortality rate is 4 times higher for pure left hand sided polymicrobial infective endocarditis vs pure RHS
How many patients with polymicrobial infective endocarditis die
1/3
List the high risk factors for developing infective endocarditis
1 Prosthetic cardiac valve
2. Prior episodes of endocarditis
3. Complex congenital cardiac defects
4. Surgically constructed systemic pulmonary shunts of conducts
List the moderate risk factors for developing infective endocarditis
- Patient ductus arteriosus
- Septal defects
- Coarction of the aorta
- Bicuspid aortic valve
- Hypertrophic cardiomyopathy
- Acquired valvular dysfunction
- MVP with mitral regurgitation
How can bacteria get into the blood stream?
- Dental abnormalities
- Intra venous drug use (IVDU)
- Wounds
- Bowel cancer
Name some common micro organisms that can cause infective endocarditis
- Streptococcus viridans
- S. aureus
- Coagulase negative staphylococci
- HACEK group
Where are Streptococcus viridans found?
In the mouth
How many cases of infective endocarditis are caused by Streptococcus viridans
50-60%
Patients with prosthetic heart valves are at greater risk of developing what?
Infective endocarditis
Name the predominant risk factor for polymicrobial infective endocarditis
Intravenous drug use (IVDU)
Where is S aureus found
On the skin
How many cases of infective endocarditis are caused by S aureus
10-20% of cases
Which patients are most likely to be affected by s aureus
Intravenous drug use
Which patients are most likely to be affected by Coagulase negative staphylococci
Prosthetic heart valve patients
Name the micro organisms found the HACEK group
- Haemophilus
- Aggregetibacter
- Cardiobacterium
- Eikenella
- Kingella
Give an example coagulase negative staphylococci
S epidermidis
Where are HACEK groups usually find?
Commensals in oral cavity
How many cases of infective endocarditis are thought to be caused by HACEK group organisms
3%
What is culture negative endocarditis
Where you suspect the patient has endocarditis but you can’t isolate the causative agent
How many cases of infective endocarditis are culture negative
5-10%
What is the cause of culture negative infective endocarditis?
- Prior antibody treatment can suppress the infection that is detected in the blood
- Organisms may be deeply embedded within enlarging vegetation so aren’t detected
- We may be unable to grow the causative organism in normal blood cultures
Give examples of organisms we can’t grow in normal blood cultures
- Coxiella burnetiid
- Chlamydia spp
- Bartonella spp
- Legionella
Describe the vegetations that may form on a patient with infective endocarditis
Friable (soft and falling apart), bulky and potentially destructive
Where are on the heart do vegetations tend to grow in a patient with infective endocarditis
Aortic valve
Mitral valve
Mainly the RHS (especially in intravenous drug users)
Describe the pathological features of infective endocarditis
- Friable, bulky and potentially destructive vegetation
- Often more than one valve affected
- Vegetation can erode into the myocardium and lead to abscess formation
- Emboli con form that contains large number of virulent organisms
What complications can arise due to emboli formation in a patient with infective endocarditis
This emboli contains a large number of virulent organism that will form an abscess at the site the emboli lodges
This can lead to septic infarcts or mycotic aneurysms
Give some clinical features of infective endocarditis
- Fever (most consistent sign)
- Non specific symptoms like loss of weight
- Murmurs
Describe the fever pattens with infective endocarditis tend to have
A rapidly developing fever, chills and weakness
How many patients with infective endocarditis had murmurs? What kind of murmur did they have?
90% of patients with left sided infective endocarditis experienced sudden onset murmurs
Which combination of clinical features would lead you to a diagnosis of infective endocarditis?
If a patient has a new heart murmur and low grade fever
Name the criteria we use to diagnose infective endocarditis
Duke criteria
What complications can be seen in a patient with infective endocarditis
- Immunologically mediated conditions like glomerulonephritis
- Micro-thromboemboli
What complications can micro- thromboemboli cause
- Splinter/ sublingual haemorrhages
- Janeway lesions
- Oslers nodes
- Roth spots
Describe laneways lesions
Erythematous or haemorrhage non tender lesions on the palms or soles
Describe oilers nodes
Subcutaneous nodules in the pulp of the digits
Describe Roth spots
They are retinal haemorrhages in the eyes
How can we remember the clinical signs and symptoms of infective endocarditis
By using the mnemonic:
FROM JANE
What do the letters in FROM JANE stand for?
Fever
Roth spots
Osler’s nodes
Murmur
Janeway lesions
Anaemia
Nail (splinter) haemorrhage
Emboli
Why is it hard to treat infective endocarditis?
As organism are protected within vegetations making them harder to treat
How do we treat infective endocarditis
High concentrations of intravenous (IV) antibiotics for 4-6 weeks (usually adjusted according to the cultural results)
Most common is penicillin
What is the association between risk of infective endocarditis and dental procedures
As of now there is no clear association with dental procedures and risk of infective endocarditis
If you have a patient with infective endocarditis what is not recommended you do?
Not recommended you prescribe them antibacterial prophylaxis and chlorohexidine mouthwash for the prevention of infective endocarditis
If you have a patient with infective endocarditis what is recommended you do?
Reduction of oral bacteraemia - high standard oral hygiene
- Reduce need for dental extractions / surgery;
- Reduce chances of severe bacteraemia if dental surgery is needed
what are the NICE guidlines for infective endocarditis
- Patients at risk of endocarditis e.g. valve replacement (see risk factors) should be warned to report to the doctor or dentist any unexplained illness after dental treatment.
- Any infection in patients at risk of endocarditis should be investigated promptly and treated appropriately to reduce the risk of endocarditis.
