Valvular heart disease Flashcards
When does rheumatic fever occur
Occurs 2-3 weeks after a streptococcal upper respiratory tract infection
What causes rheumatic fever
β-haemolytic Streptococcus
Where is rheumatic fever more common
Children in central Africa, the Middle East and India
What is rheumatic fever associated with
Poot nutrition and over crowding
What is rheumatic fever characterised by
Inflammation at multiple sites including the heart, arteries, joints and skin
Describe a heart affected by rheumatic fever
Heart generally becomes inflamed and shows signs of endocarditis, myocarditis and pericarditis
What does endocarditis at the heart valves produce
Small irregularities on the cusps of the valves called vegetations which composed of platelets and fibrin
Describe a heart affected by rheumatic fever
Generally inflamed and shows signs of endocarditis, myocarditis and pericarditis
Which valve is most frequently effected by rheumatic fever
Mitral valve
What can recurrent infections of the heart lead to
Valvular fibrosis
What is valvular fibrosis
Fusion of valve leaflets and calcification
Other than inflammation of valves what else can be inflamed in rheumatic fever
Inflammation of the large joints this produces symptoms referred to as migratory or flitting polyarthritis
Give some symptoms of rheumatic fever
- Skin rash develops (erythema marginatum)
- Subcutaneous nodules may appear
- Neurological symptoms include chorea
What can an episode of rheumatic fever increase the risk of
Developing infective endocarditis
What is infective endocarditis
A disease resulting from infection of a focal area of the endocardium
What does infective endocarditis affect
Usually the heart valves but infection can develop on the mural endocardium typically at the chordae tendineae or at the site of a congenital heart defect
Give examples of heart abnormalities that can increase susceptible to infection
- Congenital heart defects
- Calcific aortic valve disease
- Damage secondary to rheumatic fever
- Prosthetic heart valves used to replace damaged and non functional valves
Give examples of the infective agents that can cause infective endocarditis
Commensal bacteria sometimes fungal organisms
Where do commensal bacteria that cause infective endocarditis reside
- Oral cavity
- Oropharynx
- gastrointestinal tract
- genitourinary tract 5. the skin
What does colonisation of damaged endocardium edits i
- Thrombotic vegetation composed of platelets and fibrin
- the bacteria induce further platelet aggregation and fibrin deposition and inhabit an immune-privileged niche
What are local complications of infective endocarditis a consequence of
Valvular destruction causing the affected valves to become incompetent an the patietn develops a heart murmur
What risk do infected chordae tendineae
risk of rupture with fatal results that can lead to local spread of infection
List soem systemic effects of endocarditis
- Fever
- Weight loss
- Malaise
- Night sweats
- Finger clubbing
- Enlarged spleen
- Anaemia
- Mycotic aneurysms
- Heart murmur
- Microscopic haematuria
What can systemic embolism produce
Small infarcts within the brain, spleen and kidney
