OA and RA

Question 1

What is rheumatoid arthritis?

Answer 1

A chronic systemic immune disease as a result of a cell mediated immune response that attacks soft tissue and bone.

It is not limited to synovial joints and follows a stereotypical pattern of joint involvement but manifests in almost every body system.

Question 2

What is the typical presentation of fully developed RA?

Answer 2

Symmetrical inflammatory polyarthritis which is primary peripheral, with significant morning stiffness lasting well past 30 mins.

Progressive deformities and erosion with subcutaneous nodules. +ve RF and anti-CCP antibodies.

Question 3

What is the genetic component of RA?

Answer 3

HLA human leukocyte antigen (associated with worse disease) and MHC major histocompatibility complex.

Question 4

What is citrullination?

Answer 4

The conversion of the amino acid arginine into citrulline.

Question 5

Explain how environmental trigger is involved in the initiation of RA

Answer 5

Environmental trigger leads to citrullination of a host protein meaning modified protein is immunogenic, and treated like an antigen triggering an immune response.

Question 6

Explain the immune response process that occurs in RA.

Answer 6

• Citrullinated immunogenic protein formed via environmental trigger is processed and presented to T cells by dendritic cells and B cells.
• Protein presented to T cells via Human leukocyte antigen
• T cells activate B cells by releasing cytokines
• Activated B cells form plasma cells which release auto-antibodies such as RF and anti-CCP.

Question 7

What is Pannus?

Answer 7

Latin for table cloth

Grossly thickened synovium as a result of inflammation:

• autoimmune attack on synovium, synovial fibroblast proliferation causes hypertrophy and hypovascularity of synovial
• causing synovium to enlarge and spread over and between joint surfaces like a tablecloth.
• Releases damaging agents eroiding joint and infiltrating bone.

Question 8

What is a typical presentation of underdeveloped RA?

Answer 8

• Joint pain, swelling, stiffness which is polyarticular, symmetrical and small joint > large joints
• Morning stiffness lasting longer than 30 mins

Question 9

What is a swan neck deformity?

Answer 9

Hyperextension at PIP and flexion at DIP

Question 10

What is a Z deformity?

Answer 10

Flexion at the MCP and hyperextension at the interphalangeal joint

Question 11

What deformities are common in RA?

Answer 11

Swan neck deformity, Z deformity, ulnar deviation of finger due to subluxation or dislocation of joints.

Question 12

What are some extra-articular MSK Presentations of RA? (3)

Answer 12

• Bursitis
• Subcutaneous nodules
• Tendon inflammation or rupture

Question 13

What are some systemic manifestations of RA? (4)

Answer 13

• myocardial infarctions
• Stroke
• Infection
• Non-hodgkin’s lymphoma

Question 14

What are 4 red flags to look out for in RA?

Answer 14

• Atlantoaxial subluxation/instability
• Pericarditis
• Monoarticular flare (septic arthritis)
• Scleritis

Question 15

What is the significance of Atlantoaxial subluxation/instability?

Answer 15

C1 sides forward on C2 which an cause spinal cord compression with pain at the back of the head and neck, and numbness down arms.

Can result in sudden death if spinal cord injured.

Question 16

What is the significance of scleritis?

Answer 16

Sudden onset of eye pain and lacrimation which untreated sclera may become involved leading to thinning, perforation and blindness.

Question 17

What are the main key differences between RA and OA?

Answer 17

RA is symmetrical, with longer lasting morning stiffness and not affecting DIP-Js

OA is unsymmetrical with shorter lasting morning stiffness and longer stiffness after rest, affects DIP-Js

Question 18

What 3 investigations are required for an RA diagnosis?

Answer 18

1. Measure CRP and ESR baseline
2. Test for RF and anti-CCP antibodies
3. X-ray hands and feet

Question 19

What are some imaging signs of RA?

Answer 19

• erosive arthritis with joint space narrowing, subchondral erosions and ankylosis with gull wing appearance.
• Subluxations or dislocations
• Bowstringing.

Question 20

What are the principles of treatment for RA? (3)

Answer 20

• maximise health related quality of life through symptoms control
• Abrogation of inflammation
• Treatment tailored to disease activity

Question 21

What is the management of RA?

Answer 21

• Early initiation of DMARDS monotherapy with MTX and SSZ combined with short term use of glucocorticoids for flares
• consider bDMARDs e.g. TNF inhibitors and rituximab

Question 22

How can you monitor RA?

Answer 22

• Activity and drug efficacy with VAS, labs for esr and CRP and DAS 28 score
• disease progression with radiographs and functional assessment of joints
• Drugs safety with labs

Question 23

What is OA?

Answer 23

A disorder characterised by degeneration of articular cartilage, remodelling of subchondral bone, osteosclerosis and osteophytes.

Question 24

What conditions could result in secondary OA?

Answer 24

DETAMIN:

• Developmental e.g. SUFE
• Endocrine e.g. acromegaly
• Traumatic e.g. interarticular fracture
• Aseptic necrosis e.g. corticosteroids, sickle cell disease.
• Metabolic e.g. paget’s
• Inflammatory e.g. RA, gout
• neuropathic e.g. diabetes

Question 25

What are the radiological features of osteoarthritis?

Answer 25

narrowing joint space, osteophytosis, altered bone contour, bone sclerosis and cysts, periarticular calcification.

Question 26

What are the modifiable local risks of OA? (5)

Answer 26

• Muscle strength
• Physical inactivity
• Joint injury
• Joint alignment
• leg length inequality

Question 27

What are 3 age related physiological changes contributing to OA risk?

Answer 27

• Decline in proprioception
• Decrease in muscle strength (sarcopenia)
• Changing shape of bones