Three stages of synovial membrane in RA?
- Exudative phase
- Infiltrative phase
- Synovial stage
Exudative stage of synovial membrane?
acute synovitis (congestion and edema of the synovial membrane) + capillary proliferation and permeability (exudate in joint).
Infiltrative phase/stage of synovial membrane?
accumulation of RBC (phagocytosed of these cells deposition of hemosiderin), PMN, leukocytes, small lymphocytes (predominant cell), distinct multinucleated giant cells (not specific for RA), produce small nodular aggregates superficially called Allison-Ghormley nodules
Synovial stage of synovial membrane?
synovial cells enlarge and multiply producing papillary-like fronds, can get metaplasia of connective tissue to fibrocartilage, hyaline cartilage, and even bone (not the same as cartilaginous/osseous debris found in later stages of RA)
- Increased amounts of turbid yellow-green synovial fluid of decreased viscosity is produced -> increased amounts of globulins (A: G ratio N=2:1, becomes 1:1),
- Capsular distension, soft tissue swelling and hyperemia
4 early radiographic signs of RA?
- ST swelling
- Hyperemia (periarticular osteoporosis)
- Bilat symmetric narrowing
- Marginal erosions
RA of the robust reaction type?
develop large radiolucent cystic areas in RA patients who maintain high level of physical activity -> physical stress which elevates intra-articular pressure increases rate at which synovial fluid and or pannus is forced into the bone
- Mechanisms of joint decompression?
(1) Formation of synovial cysts
(2) Formation of subchondral cysts
(3) Fistulae/sinus tracts between articulation and skin
sinus tract/fistulous rheumatism mechanism?
necrotic bone fragments occurring in rheumatoid joints, if numerous and large, may be extruded through the skin.
Bursal involvement in RA
- Involved because they have a synovial lining, bursa usually communicate with joint which allows spread
- 5% get bursal involvement, M/C in popliteal region and olecranon, also subacromial (subdeltoid), retrocalcaneal, and in wrist and foot
posterosuperior calcaneus, olecranon, inferior surface of acromion and distal clavicle, outer aspect of distal ulna from extensor carpi ulnaris tenosynovitis
Cause of edema in RA?
causative factors include anemia, fluid retention, hypoalbuniemia, venous or lymphatic obstruction, increased capillary permeability
calcification in RA?
– rare, consider overlap with mixed CT disorder or collagen vascular syndromes
Diagnostic Criteria for RA? (7)
(1) Morning stiffness in/around joints lasting at least 1 hr before maximum improvement.
(2) Soft tissue swelling (arthritis) of 3+ joint areas observed by physician
(3) Swelling (arthritis) of PIP, MCP, or wrist joints
(4) Symmetric arthritis
(5) Rheumatoid nodules
(6) RF +ve
(7) Radiographic evidence of erosions &/or periarticular osteopenia in hands &/or wrists
Diagnostic criteria must be present how long?
Classic RA: >7 criteria with swelling > 6 months
definite = >5 criteria with continuous joint Sx >6 wks
probable = >3 criteria with joint Sx 4-6 wks
probable = at least 2 criteria with joint Sx at least 3 wks
Clinical presentation of RA? (age, sex, sx, etc)
- 2-3x M/C female, 25-55 yoa, onset typically insidious but may follow physical or psychic stress
- Prodromal Signs – fatigue, anorexia, weight loss, malaise, muscle pain and stiffness
- Acute arthritic attacks are sudden onset, persist for hrs-days, subside without residual disability
- A paralyzed limb will notably not develop rheumatoid arthritis.
RA is typically symmetric, when is this not true?
symmetry may be absent early in disease as 5-20% have monoarthritis which can last several months
asymmetric or unilateral in pts with neuro deficit, where RA is contralateral to side of paralysis
(RA may be more severe in dominant hand and overused joints)
symmetry is less common in males
Neuropathies in RA?
encephalopathy, myelopathy (do to vasculitis, vertebral subluxation, rheumatoid nodules), peripheral neuropathy (stocking distribution of sensory impairment, wrist and foot drop)
Felty’s syndrome?
RA, splenomegaly, leukopenia, weight loss, anemia, lymphadenopathy, chronic leg ulceration, abnormal skin pigmentation, recurrent infections, M/C female.
Sjogren’s syndrome in RA?
keratoconjunctivitis sicca, xerostomia (dry mouth), connective tissue disease (60-70% of pts, may be identical to RA)
Caplans syndrome?
combination of pneumoconiosis and rheumatoid arthritis
Other conditions that are RF+?
syphillis and SLE.
RA Labs?
- Moderate normo/hypochromic anemia, elevated ESR and parallels disease activity, elevated C-reactive protein in active disease state, RF (sheep agglutination test for group of macroglobulins), LE phenomenon (8-27%)
Term for multiple marginal erosions seen throughout the carpals
spotty carpal sign
Also seen in: gout, tuberculous arthritis and sudecks atrophy
Term for radial rotation of proximal row of carpals (70%), and ulnar deviation of MCP joints?
zig-zag deformity
What is - Caput ulnae syndrome ?
pain, limited motion, dorsal prominence of distal ulna do to diastasis at the radioulnar joint with possible dorsal displacement of the ulna causing extensor tendon rupture.
