1 Flashcards
Rheumatoid Arthritis – chronic multisystem disease of unknown origin
RA is the Gold Standard of inflammatory arthritis
Polyarthritis – involves more than one joint
o Foot is almost always involved
Inflammation in the synovium – causing a synovial pannus
Epidemiology of RA
Worldwide
Occurs in 1% of US adults
3:1 female:male
Peak age = 35-45 yrs (incidence increases w/ age
Pathogenesis of RA
1) mutation predisposes someone to
o 90% have HLA-DR4 gene
o A response to a synovial autoantigen
Pathogenesis of RA
2) cytokines perpetuate synovial inflammation causing T-cells to respond
o CD4 T-cells – play primary role in RA inflammation TH1 CD4 – implicate chronic inflammation
o Examples of cytokines
TNFα – key player in synovial inflammation; controls production of collage proteinases
Pathogenesis of RA
3) autoantibodies, specific for the Fc Fragment of IgG of synovium, can be found and used as diagnosis
o RF – seen in 85% of RA; major lab hallmark of RA
associated w/ severe disease
o Anti-CCP – autoantibodies to cyclic citrullinated peptides; have high specificity in identifying pts prone to irreversible damage, but a negative result does not rule out disease
Appear early in disease – pre-clinical stage of joint destruction
Levels skyrocket before RA diagnosis
o +RF plus +CCP = RA w/ 30-40% sensitivity and 98-100% specificity
Pathogenesis of RA
4) inflammation continues to form an invasive, hyperplastic synovial membrane (pannus)
o Synovial Pannus – mass of chronic inflammatory granulation tissue that destroys joints by
eroding and attack soft tissue
Morphology of RA
1) Synovial Phase – buildup of synovial fluid
o Joint space widening
o Joint is swollen and cool
2) Periarticular Phase – soft tissue swelling and beginning of pannus formation
o Pannus covers joint surfaces
3) Erosion – erosion into bone begins at intra-articular bare areas
4) Chondrolysis – cartilage loss begins causing joint space narrowing
5) Erosions continue into subchondral cortex
6) End Stage – fibrous ankylosis (fusion of joint)
Systemic Manifestations of RA – RA is systemic
Skin – RA nodules in 50%
Ocular – keratoconjunctivitis sicca
Cardiac – pericardial effusions
Pulmonary – interstitial fibrosis and nodules
Hematologic – hypochromic/microcytic anemia and vasculitis
Neurologic – tarsal tunnel syndrome, Cervical spine instability
Systemic Manifestations of RA – RA is systemic
Associated ds
o Fatigue
o Morningstiffness o Nodules
o Vasculitis, Scleritis
o Sjogren’s Syndrome o Lymphadenopathy
o Peripheral neuropathy o Pleuritis
o Interstitial lung fibrosis, Pericarditis
o Amyloidosis, Splenomegaly, Felty’s Syndrome
Diagnostic Criteria for RA – need 4 for diagnosis
Morning stiffness > 1hr
Arthritis in > 3 joints – simultaneous w/ fluid
Arthritic hand joints – at least one joint
Symmetric Arthritis – bilateral
Rheumatoid Nodules – non-calcified subQ nodules over bony prominences, extensor surfaces, etc.
Serum RF – seen in 85%
Radiographic findings in AP hand and wrist
Pedal Involvement of RA
1:10 have onset of RA w/ pedal joint attack preceding hands
Clinical Syndromes:
o Severe Hallux Valgus (w/ or w/o bunion)
o Flatfoot & hyperpronation
Decreased calcaneal inclination
Vertical talus
o Depression of met heads w/ or w/o atrophy of plantar fat pad
Anterior migration of fat pad w/ increased pressure on met heads (metatarsalga)
o Retrocalcaneal bursitits
o Tarsal Tunnel syndrome – plantar “burning” paresthesia
Pedal Involvement of RA
90% of RA has pedal involvement
Foot is initial presentation of RA in 1:10 (preceding hands; 10-20%)
Pedal Locations of RA o MPJ’s and IPJ
Most common – 5th MPJ
2nd most common – medial 1st IPJ (over 50% of cases)
Not common in PIP’s and DIP’s
o Chopart’s joint (TN) – seen in 40% o Lisfranc’s Joint – seen in 36%
o Posterior Facet of STJ – seen in 29% o Cuneiform Joints – seen in 28%
o CC Joint – seen in 25%
o STJ and Ankle joint – not as common
Early RA Radiographs
Soft Tissue Swelling – usually lateral 5th MPJ
Periarticular Osteopenia/Osteoporosis
o Gray tone parity – the tons on the inside of the bone are the same as those outside the bone of the soft tissues
Early RA Radiographs
Concentric Joint Space Narrowing – due to irreversible cartilage loss o Chondrolysis – a response to pannus extension across a joint
Concentric cartilage loss
Early RA finding – can happen in wks/months
Occurs before bone erosions – allows an earlier diagnosis *note – in Robust RA, you’re less likely to have joint space
narrowing (spares the joint space)
