MSK - Arthritis Flashcards
Features of Primary OA
Asymmetrical joint space narrowing, subchondral sclerosis and cystic change, osteophytosis
NO periarticular osteopenia, NO erosions
Features of Rheumatoid Arthritis
Hands: Diffuse, symmetric joint space narrowing, marginal erosions, periarticular osteopenia, soft tissue swelling, joint subluxations (ulnar deviation at MCPs), ankylosis in late stage
Feet: MTP joints most common
Cervical spine: leading to anterior or vertical atlantoaxial subluxation
Shoulder: erosions in lateral aspect of humeral head, penciling of clavicle, chronic cuff tearing and high riding humerus
What conditions classically cause bilateral and symmetric SI joint involvement
Ankylosing spondylitis, IBD
vowels of PAIR
Erosions first involve the lilac side of the joint (cartilage is thinning and has areas of fissuring)
What conditions classically cause unilateral, asymmetric SI joint involvement
Reiter’s, psoriasis consonants in PAIR
+ infection, DJD, gout
Erosions first involve the lilac side of the joint
Features of Psoriatic Arthritis
Hands: Bilateral, asymmetric soft tissue swelling (sausage digit), marginal erosions in DIP and PIP jts, pencil-in-cup, fluffy periostitis +/- ankylosis and arthritis mutilans (severe cases) +/- opera glass hand deformity
Feet: Great toe IP and MTP jts most commonly affected, ivory phalanx (specific for PA), plantar calcanea spur with periosteal reaction
Spine: Bulky, lateral outgrowths
PRESERVED MINERALIZATION
Features of Gout
Well-defined punched our erosions (overhanging edges), soft tissue nodules, random distribution
*no osteopenia, joint spacing preserved until late!
Diseases associated with chondrocalcinosis
Cations - calcium, copper, iron)
Crystals - CPPD, gout
Cartilage - OA, acromegaly, ochronosis
Characteristic feature of lupus
Reducible subluxations of MCP and PIP joints (best seen on Norgaard/ball catcher/AllState view)
Collagen vascular diseases causing soft tissue calcification
Scleroderma (subcutaneous), dermatomyositis/ polymyositis (intramuscular - sheet like), SLE (very rarely seen in lupus, usually subcutaneous and lower extremity)
Classic appearance of hemochromatosis
Primarily involves the MCP joints, hook-like osteophytes of metacarpal heads and joint space narrowing
5 D’s of Charcot joint (hypertrophic variant)
Destruction, debris, disorganization, dislocation, density
Imaging appearance in hemophilia
Recurrent bleeding into joint = synovial hypertrophy and hyperaemia
Epiphyseal overgrowth and early growth plate fusion; gracile diaphyses; secondary degenerative changes including periarticular erosions, JS narrowing etc.
Key findings: knee>elbow>ankle> hip>shoulder
Elbow - enlarged radial head, widened trochlear notch
Knee - squaring of patella and widened intercondylar notch
MRI: Increased ST around joints due to iron deposition, low T2 signal synovium from hemosiderin
NB: Pseudotumour of hemophilia - intraosseous/ subperiosteal bleeding leading to hematoma/soft tissue mass (well circumscribed, sclerotic margins, endosteal scalloping)
Lumpy, bumpy arthridides
Gout, amyloid, sarcoidosis, multi-centric reticulohistiocytosis
Features of DISH
Bridging anterior osteophytes, spanning at least 4 levels, preserved intervertebral joint spacing, associated with ossification of the posterior longitudinal ligament (OPLL)
Imaging findings in erosive OA
Gull-wing appearance at DIP joints from central erosions
Soft tissue swelling
Same distribution as degenerative OA
Elderly females
Normal atlantodental interval
<2.5 mm (adults)
<5 mm (children)
Imaging findings in ank spond
First involvement of SI joints, symmetric
Then spinal involvement including erosions (Romanus lesions, shiny corner), syndesmophytes (bamboo spine)
shoulder (hatchet deformity), hips (bilateral axial migration and collar osteophytes)
Features of reactive arthritis
Predominantly affects the FEET
Similar findings to PA - ST swelling, joint space loss, marginal erosions, osteopenia
Calcaneus - proliferative changes, erosions, enthesophytes
Features of scleroderma
Dystrophic soft tissue and periarticular calcs, contractures, atrophy, acroosteolysis
DDx acro-osteolysis
1) Collagen vascular disease (scleroderma)
2) Neuropathy i.e. Diabetes
3) Polyvinyl chloride
4) Thermal injury
5) HyperPTH
6) Hajdu-Cheney (short stature, craniofacial abN, progression acroosteolysis)
Findings in CPPD
Most commonly seen in wrist, hands, knees, pubic symphysis
TFCC –> SLAC wrist
Hook like osteophytes, diffusely in MC heads (versus hemochromatosis which is 2nd and 3rd)
Chondrocalcinosis, isolated patellofemoral involvement or large subchondral cysts suggest the diagnosis in knee
DDx: hook like osteophytes metacarpal heads
Hemochromatosis (2nd and 3rd metacarpals)
CPPD (diffuse involvement of MCPs)
Imaging findings in acromegaly
Widened joint space first due to cartilage hypertrophy, narrowing later in disease from secondary OA
Beak-like osteophytes in metacarpal heads
Spade-like enlargement of terminal tufts
Imaging findings amyloid arthropathy and causes
Infiltration of bones, soft tissue and joints with amyloid
Periarticular soft tissue swelling, joint effusion and large subchondral erosions/cysts - mimics inflammatory arthritis
Shoulder pad sign - bulky soft tissue in the shoulders with atrophic musculature
Low signal on MRI due to amyloid deposition
most commonly related to chronic hemodialysis
Imaging findings in multi-centric reticulohistiocytosis
Infiltration of histiocytes into soft tissues and joints (1/4 cases seen in malignancy - breast and ovarian)
Bilateral symmetric involvement
Sharp, well defined marginal erosion (striking, symmetric)
Soft tissue nodules
Arthritis mutilans in severe cases
*Can mimic inflammatory arthropathy (RA) and gout, but has rapidly progressive joint destruction
JIA imaging findings
Epiphyseal overgrowth, elongated/gracile bones
Premature fusion of GPs
Ankylosis in wrist and facet joints of c-spine (ddx cervical spine ankylosis: Klippel-Feil syndrome)
Imaging findings atrophic variant of Charcot joint
Humeral head resorption, sharp margins (looks like Hill Sachs), debris in joint
Often associated with syringomyelia
Classic bone findings in sarcoid
Occur in 20% of pt’s with sarcoid
Lace-like lytic lesions in middle or distal phalanges
Articular surface is spared
Can have dactylitis, tenosynovitis
Nodular soft tissue and muscular granulomatous deposits (erythema nodosum)
What is Jaccoud arthropathy?
Previously thought to be related to rheumatic fever, also seen in psoriatic arthritis, malignancy, IBD
–> Ligamentous laxity
Reducible subluxations MCP joints (similar to SLE)
Which condition gives Hatchet deformities?
Humeral head/GT erosions from AS, related to enthesopathy at RC insertion
- ddx: hill sachs
Causes of chondrocalcinosis
3 C’s
- crystals - CPPD, sodium urate (gout)
- cations - calcium, copper, iron
- cartilage degeneration - OA, acromegaly, ochronosis
