RA

Question 1

DEFINITION

Answer 1

RA is a chronic (life-long), systemic, autoimmune disease of unknown etiology that affects the diarthrodial (movable) joints, that involves an invasion of inflammatory cells into the synovium leading to synovial hyperplasia and edema called ‘pannus’.

PANNUS : Pannus is Latin for cloth or garment. In medicine, pannus is any abnormal tissue that: Contains blood vessels (necessary for tissue growth) Covers up a normal body structure.

Question 2

WHERE DOES IT AFFECT?

Answer 2

it affects mainly small and medium joints (of the hands and feet), and rarely large joints (e.g. shoulder, knee) and various organs, such as the lungs and vessels. Locally, inflammatory cells invade the synovium, otherwise relatively acellular, leading to hyperplasia and pannus formation that causes the damage of cartilage, erosion of bone and finally loss of function of the affected joint.

Question 3

the chronic inflammation favors …

Answer 3

an atherosclerotic process that puts these patients at high risk of myocardial infarctions and strokes at a much younger age relatively to the general population.

Question 4

PREVALANCE

Answer 4

● Prevalence - It is a very frequent disease. The most common polyarthritis (> 4 joints are involved) . The prevalence in western countries is 0.5-1% of the entire population. This means 1 or 2 people out of every 100 people.

Question 5

INCIDENCE

Answer 5

16.5 cases (〖10〗^5) for year in southern Europe, 29 cases in northern Europe and 38 cases in North America.

Question 6

SEX

Answer 6

RA is more prevalent in females (2.4:1), this ratio decreasing over time. The disease with highest emphasis on this difference is systemic lupus erythematosus where the ratio is 9:1.

Question 7

AGE

Answer 7

The peak of the gaussian curve of incidences is found between the 4th and 5th decade (midlife), however, the disease can be found at younger or older individuals. If the disease occurs before the age of 16y it is called ‘idiopathic juvenile arthritis’ (which will be covered in another lecture).

Question 8

MAIN CHARACTERISTICS

Answer 8

1. Autoantibody production- 2 in particular:
   a. Rheumatoid factor- an IgM directed against the FC portion of IgGs.
   b. anti-citrullinated protein antibody (ACPA)
2. Synovial inflammation and hyperplasia - giving rise to a ‘Pannus’ (swelling).
3. Cartilage and bone destruction n- that occurs due to the inflammatory process. If the disease is not detected and treated appropriately it can cause permanent damage, deformity and disability.
4. Systemic features - additional systemic features include cardiovascular, pulmonary and psychological and skeletal problems.

Question 9

Genetic Background

Answer 9

production of ACPA is significantly correlated with smoking as well as the presence the HLA-DRB1 SE allele