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)