Condition- Rheumatic fever

Question 1

Which organism commonly causes rheumatic fever

Answer 1

Group A Beta-haemolytic Strep (GAS). e.g. Strep pynogenes

Question 2

Which parts of the body may be damaged in rheumatic fever- which part causes the most severe symtpoms?

Answer 2

• Joints
• Brain
• Skin
• HEART- the heart valves in particular

Question 3

Patients with rheumatic fever commonly have which condition before the full multi-system autoimmune disease?

Answer 3

May have a group A strep throat infection

(streptococcus pharyngitis)

Question 4

Describe how Strep Pyogenes leads to autoimmunity.

i) which protein on the strep pyogenes antigen does the immune system mount an attack against?
ii) how does this lead to autoimmunity

Answer 4

1. Strep Pyogenes has an M protein which is highly antigenic
2. Activates innate immune system
3. B + T cells produce IgG and IgM abs + killer T cells activates
4. BUT THEN… there’s a cross reactive immune response = molecular mimicry
5. The antibodies which were meant to be against the M protein are similar to antigens on myocardium and joint tissue etc.

Question 5

Which age group is at a higher risk of developing rheumatic fever?

Answer 5

CHILDREN (5-15yrs)

Question 6

How many weeks after strep throat does rheumatic fever present?

Answer 6

2-5 weeks

Question 7

List some symptoms of rheumatic fever (classify them)

i) general
ii) specific systems

Answer 7

GENERAL:

• fever
• malaise
• anorexia

HEART

• breathlessness
• chest pain
• palpitations

JOINTS

• painful, swollen
• reduced movement/ function

Question 8

Which valves are most susceptible to damage in rheumatic fever?

Answer 8

1. Mitral
2. Aortic

Question 9

What is the most common cause of death in acute rheumatic fever?

Answer 9

Myocarditis => inflammation + necrosis => imparied contraction => Cardiac failure

Question 10

Which criteria is used to diagnose rheumatic fever- and state the criteria

Answer 10

REVISED JONES CRITERIA

• Evidence of recent strep infection
• 2 major criteria or
• 1 major + 2 minor criteria

Question 11

List some ways you ca check for evidence of GAS infection to fulfill the Jones criteria for Rheumatic fever…

Answer 11

• Positive throat culture – but usually negative by the time symptoms occur
• Rapid streptococcal antigen test +ve
• Elevated/rising streptococcal antibody titre
• Recent scarlet fever

Question 12

State the mnemonic for and list 5 ‘major’ signs which comprise the diagnostic criteria for rheumatic fever

Answer 12

CASES

• Carditis: mitral/aortic regurg, pericardial rub
• Arthritis: Migratory Polyarthritis/ monorarthritis (often large joints)
• Subcutaneous nodules: large firm painless nodules on extensor surface
• Erthema maginatum: red, raised edges, clear centre, proximal limbs + trunk
• Syndeham’s choreo: basal ganglia involvement

Question 13

List some signs of carditis on physical examination of someone with rheumatic fever

Answer 13

• tachycardia
• murmurs (mitral/ aortic regurg often)
• Pericardial rub
• Cardiomegaly
• Conduction Defects

Question 14

List some of the minor criteria for rheumatic fever

Answer 14

PRAPP

• Pyrexia
• Raised ESR/CRP
• Arthralgia (only if arthritis not present as major criteria)
• Prolonged PR interval (only if carditis not present as major criteria)
• Previous rheumatic fever

Question 15

What might you see on an ECG of someone with Rheumatic fever

Answer 15

• Saddle ST-elevation + PR segment depression (diffuse): Pericarditis
• Arrhythmias

Question 16

Which investigations should you conduct on a patient with suspected Rheumatic fever?

Answer 16

• BEDISIDE: throat swab for strep, ECG for signs of pericarditis/ arryhtmias
• BLOODS: FBC (high WCC), high ESR/CRP, rising antistreptolysin O titre
• IMAGING: Echocardiogram: pericardial effusion, myocardial thickening/ dysfunction, valvular dysfunction (PANCARDITIS Signs)

Question 17

Which antibody might be elevated in the bloods of someone with rheumatic fever?

Answer 17

antistreptolysin O