Inflammatory Arthritis

Question 1

Where is the shared epitope of Rheumatoid Arthritis?

What is its clinical association?

what are other risks for these people?

Answer 1

It is HLA-DRB1

It is associated with the most severe disease with seropositivity (anti-CCP) and erosive disease

smoking is a super bad thing - increases their risk by ~16x

Question 2

what does the anti-CCP do?

Answer 2

it is an autoantibody against citrullinated peptide. In vitro, we can demonstrate reaction between these, but we’re not sure exactly how it causes disease in the wild

smoking seems to increase activity of PAD (this is the enzyme that citullinates peptides)

Question 3

what are the diagnostic criteria for RA?

Answer 3

used to be the 1987 ARA criteria, but in 2010 it was changed to increase sens in early RA

slightly elaborate, but it identifies features discriminating patients with inflamm arthritis into two groups - one with stable disease and one with persistent/erosive disease (RA)

based on number of joints (and which joints), serology, acute phase response and symptom duration.

score of >/= 6 is definite RA

Question 4

what is the diagnostic criteria for psoriatic arthritis?

Answer 4

1. evidence of psoriasis, personal or family history
2. typical psoriatic nail changes
3. neg RF
4. either current dactylitis or his of diactylitis
5. radiographic juxta-articular new bone formation - ill defined ossification near joint margins (not osteophytes)

Question 5

when does reactive arthritis occur?

Answer 5

usually within first 6 - 12 weeks AFTER the infection has subsided

most then subside by 3 - 6 months and 75% complete remission by 2 years.

Question 6

what are higher risk features of reactive arthritis?

Answer 6

hip involvement
high ESR >30
poor efficacy of NSAIDs
spinal stiffness
age of onset <16 years
dactylitis

Question 7

what are the patterns of IBD associated arthritis?

Answer 7

1. pauci-articular (<5 joints)
   - this typically affects the knees, is asymmetric, and chronologically associated with gut relapse and erythema nodosum
2. poly-articular (5 or more)
   - typically hands, typically MCPs, symmetrical, independent of gut disease
   - NO ASSOCIATION with EN
3. Axial disease

Question 8

what are the PBS criteria for biological DMARDs?

Answer 8

patient has severe arthritis
has signed consent
is taking MTX
has failed six month intensive DMARD treatment with minimum of 2 agents, each for 3 months.

active disease on joint count and blood work (ESR and CRP)

Question 9

what are the predictors of poor outcome in RA?

Answer 9

chronic unremitting disease (esp in elderly!)
high baseline disease activity score
female gender
poor functional status
low SES status
low education
systemic or extra articular features
co-morbidity
early erosive disease
persistent acute phase response
autoantibodies
HLA-DRB1 status
significant delay in onset of DMARD and 'roids