RA

Question 1

What serum marker is typically positive in RA?

Answer 1

rheumatoid factor

Question 2

What is the RF antibody directed against?

Answer 2

IgG which activates the complement cascade

Question 3

erosion in RA occur where in the joint?

Answer 3

Marginal erosions at the “bare area”

Question 4

What is the “bare area”?

Answer 4

region of exposed bone just within the joint capsule that is not covered by thick cartilage

Question 5

Type of joint space narrowing in RA

Answer 5

symmetric joint space narrowing

Question 6

Radiographic hallmarks of RA

Answer 6

• marginal erosions - soft tissue swelling - symmetric joint space narrowing - periarticular osteopenia - joint subluxations

Question 7

Earliest radiographic findings of RA

Answer 7

soft tissue swelling and peri-articular osteopenia (reflects synovitis and hyperemia)

Question 8

First erosions to occur in the hand in RA patients

Answer 8

• radial aspects of the second and third metacarpal heads - ulnar styloid - bases of the proximal phalanges

Question 9

Common place for RA involvement in the feet

Answer 9

• MTP joints in the forefoot - talocalcaneonavicular joint

Question 10

Hip deformity associated with RA

Answer 10

protrusio deformity - >3mm medial migration of the femoral head beyond the ilioischial line in males and >6mm in females

Question 11

Typical migration of the femoral head in RA

Answer 11

axial (symmetric joint space narrowing)

Question 12

osteophytes plus symmetrical cartilage space narrowing in the knee

Answer 12

secondary OA in the setting of inflammatory arthropathy (like RA)

Question 13

cervical spine is involved in what percentage of RA pts?

Answer 13

70%

Question 14

Common association of RA in the cervical spine

Answer 14

atlantoaxial subluxation: - anterior: laxity of transverse ligament - vertical (atlantoaxial impaction): odontoid through foramen magnum secondary to facet erosion and collapse - posterior: due to odontoid fx

Question 15

Finding in the shoulder commonly associated with RA

Answer 15

osteolysis of the distal clavicle (“penciling” of the distal clav)

Question 16

How commonly does RA involve the elbow?

Answer 16

1/3 of pts

Question 17

Answer 17

dens involvement in RA

Question 18

Answer 18

Bad RA in the hands

• MTP erosions with ulnar deviation (SLE would be ulnar deviation without erosions)
• first carpal row erosions
• ulnar styloid erosions
• PIP erosions

Question 19

Answer 19

RA

• marginal erosions in the “bare areas” - especially 2nd and 3rd MCP
• periarticular osteopenia

Question 20

Answer 20

Boutonniere deformity - contracture associated with RA

• flexion contracture of a PIP and extension of DIP

Question 21

Answer 21

swan neck deformity-associated with RA

Question 22

Answer 22

hitch-hiker thumb - associated with RA

• flexion of the MCP, hyperextension of the IP joint
• also know as Z-thumb or duckbill thumb

Question 23

Answer 23

Felty syndrome

• RA
• splenomegaly
• neutropenia

Question 24

Pt also has RA and the following pulmonary findings in the image

Answer 24

Caplan syndrome: RA +pneumoconiosis

Question 25

Answer 25

[Rice bodies](https://radiopaedia.org/articles/rice-bodies-musculoskeletal?lang=us) in the knee, associated with RA

Question 26

Answer 26

anterior atlantodental subluxation in RA patient

Question 27

Answer 27

erosion of the dens in RA

Question 28

Answer 28

bialteral [**_acetabular protrusio_**](https://radiopaedia.org/articles/acetabular-protrusion-1?lang=us) in an RA pt * femoral head crosses medially to the ilioischial line \>3mm in men and \>6mm in women.