Clinical Aspects of Rheumatoid Arthritis

Question 1

What is the definition of rheumatoid arthritis?

Answer 1

RA is a chronic autoimmune systemic illness characterised by a symmetrical peripheral arthritis and other systemic features
It is one of the commonest chronic illnesses and may be associated with joint damage, disability and premature mortality

Question 2

What is the prevalence of rheumatoid arthritis?

Answer 2

Approx 1% of population

Question 3

What is the incidence of RA in Grampian?

Answer 3

Approx 200 new cases/year in Grampian

Question 4

What is the F:M rate of RA?

Answer 4

F:M
3:1

Question 5

What is the age of onset of RA?

Answer 5

Peak age 4th-5th decade
May occur at any age from 16 years
Before this age it is classed as juvenile onset

Question 6

What is the genetic aetiology of RA?

Answer 6

No single causative gene but there is a genetic component - causes disease when there is interaction with environmental factors
Overall incidence rises to 2-4% in siblings and 12-15% in monozygotic twins
Genetic contribution to RA estimated to be around 50-60%
Closest association with specific amino acid sequences at positions 70-74 or DRB1

Question 7

What environmental factors have a role in the aetiology of RA?

Answer 7

Smoking

Chronic infection e.g. periodontal disease

Question 8

What is the immunological investigation of suspected RA?

Answer 8

Rheumatoid factor - IgG, IgM

Anti-cyclic citrullinated antibodies e.g. anti-CCP, ACPA - more clinically valuable with greater sensitivity

Question 9

What is the imaging investigation of suspected RA?

Answer 9

X-ray
US
May be useful in determining extent/number of joints affected if considering surgical treatment

Question 10

What are the symptoms of RA?

Answer 10

Pain
Stiffness
Immobility 
Poor function 
Systemic symptoms

Question 11

What are the signs of RA?

Answer 11

Swelling
Tenderness
Redness/heat
Limitation of movement

Question 12

What are the systemic features of RA?

Answer 12

Non-specific

• fatigue
• lassitude
• weight loss
• anaemia

Organ specific
- eyes, lungs, nerves, skin and kidneys affected e.g. systemic vasculitis, conjunctivitis

Long-term

• CVS problems
• malignancy

Question 13

How is RA assessed?

Answer 13

Disease activity score
DAS < 2.4 represents clinical remission
DAS > 5.1 represents eligibility for biologic therapy

Question 14

What percentage of cases of RA are diagnosed during working life?

Answer 14

75%

Question 15

What percentage of people with RA stop working within 2 years of diagnosis?

Answer 15

Approx 33%

Question 16

What percentage of people with RA are unable to work due to disability within 10 years of diagnosis?

Answer 16

Approx 50%

Question 17

How many days sick leave per year will a person with RA have on average, compared with the normal population?

Answer 17

On average 40 days sick leave per year compared to 6.5 in normal population