Rheumatic fever Flashcards
Define rheumatic fever
An autoimmune condition usually as a result of Streptococcus Pyogenes which can lead to inflammation and mitral stenosis
Describe the pathophysiology of rheumatic fever
- It is triggered by Beta Haemolytic Group A streptococcus bacteria, usually Strep Pyogenes and usually presents as pharyngitis
- Antibodies are produced to fight off the infection but lead to the destruction of other cells, leading to cell destruction and inflammation
What type of hypersensitivity reaction is rheumatic fever?
Type 2
What type of disorder is rheumatic fever?
a multi-system disorder and affects many things such as the heart, joints, skin and the nervous system
What does 50% of cases of rheumatic fever progress to?
rheumatic heart disease
What happens on heart muscle in rheumatic heart disease?
- The M protein on S. Pyogenes forms a cross link with the heart muscle and the antibodies target this cross link
- This is known as molecular mimicry
What does rheumatic heart disease usually affect and cause in the heart?
Usually affects the mitral valve and thickens leaflets causing mitral stenosis
What is the epidemiology of rheumatic fever?
It is rare in the UK due to early strep treatment so it is usually seen in young people from developing countries
What are symptoms of rheumatic fever?
- New Murmur (Mitral Stenosis usually, mid diastolic murmur)
- Sydenham’s Chorea (uncoordinated jerky movements)
- Pyrexia
- Erythema Nodosum (swollen red bumps)
- Joint Pain
- Shortness of breath
What can be seen in histology of rheumatic fever?
can see things called Aschoff bodies in affected valves
What is used to diagnose rheumatic fever?
- Throat Swab
- Chest X-Ray (for cardiomegaly, heart failure and signs of mitral stenosis)
- Echo (severity of valvular damage)
- Jones criteria
What is the Jones criteria?
It dictates there MUST be a recent S. Pyogenes infection AND 2 major signs OR 1 major sign accompanied by 2 minor signs
What are the major signs of the Jones criteria?
MAJOR: JONES
J – Joint arthritis
O – Organ inflammation, such as carditis
N – Nodules
E – Erythema marginatum rash
S – Sydenham chorea
What are the minor signs of the Jones criteria?
MINOR: FEAR
Fever
ECG Changes (prolonged PR interval) without carditis
Arthralgia without arthritis
Raised inflammatory markers (CRP and ESR)
What is the treatment of rheumatic fever?
- Antibiotics – Use IV Benzylpenicillin STAT and then use phenoxymethylpenicillin for 10 days
- This is to fight against the Strep bacteria
Clinical features can be treated separately
