Seronegative spondyloarthropathies Flashcards
Seronegative spondyloarthropathy defined by negative _____________ and positive ___________
negative rheumatoid factor positive HLA-B27
What is a romanus lesion?
seen in AS erosions of the anterior superior or inferior edges of the vertebral body endplates caused by enthesitis
What is a shiny corner?
seen in AS represents sclerosis of prior Romanus lesions at the corners of the vertebral bodies
Patterns of PsA:
oligoarthritis or polyarthritis bulky asymmetric bridging ill-defined bone production fusiform soft tissue swelling (sausage digit) DIP erosions –> telescoping digits pencil in cup deformity main-en-lorgnette (opera glass hand) deformity
Sequela of infectious diarrhea, urethritis, or cervicitis
Reactive arthritis (Reiter’s)
Sausage digit
PsA
pencil in cup = PsA
Do erosions in seronegative spondyloarthropaties affect the ischial or iliac aspect of the SI joint?
iliac aspect of the join
Telescoping digits in PsA. Arthritis mutilans
main-en-lorgnette
PsA (and Rheumatoid Arthritis)
large lateral osteophytes is associated with PsA
Bulky lateral bony outgrowths
PsA and Reactive arthritis
ivory phalanx = PsA
Asymmetric sacroilitis differential
- Psoriatic arthritis
- Reactive arthritis
Mnemonic for sacroilitis:
“PAIR”
- Psoriatic arhtritis
- Ankylosing spondylitis
- IBD arthropathy
- Reactive arthritis
Consonants are asymmetric Vowels are symmetric
main-en-lorgnette (opera glass hand) in PsA
erosion at retrocalcaneal bursa - seen in inflammatory arthropathies but most commonly associated with REACTIVE arthritis/”reiter’s”
IBD sacroilitis. Notice the lead pipe deformity of the bowel (red arrow) and bilateral symmetric sacroilitis.
What are the four seronegative spondyloarthropathies
Ankylosing spondylitis Psoriatic arthritis Reactive arthritis (Reiter’s) Inflammatory bowel disease associated arthropathy
What portion of the SI joints are affected in seronegative spondyloarthropathies?
inferior aspect since this portion is a synovial (diarthrodial) joint
Romanus lesions (erosions at the superior anterior endplate) seen in seroneg spondyloarthropathies like AS and IBD arhtropathy
Spine signs in AS
- Romanus lesion: erosions of the anterior superior or inferior edges of the vertebral body endplates caused by enthesitis
- shiny corners: represents sclerosis of prior Romanus lesions at the corners of the vertebral bodies squaring of the vertebral body: due to ossification of the periosteum of the vertebral body
- Bamboo spine: syndesmophytes
- Dagger spine: ankylosis of the interspinous ligament Andersson lesion: pseudarthrosis occuring in a completely ankylosed spine
Seronegative spondyloarthropathy that commonly affects the feet
reactive arthritis (previously Reiter disease)
Fluffy periostitis
psoriatic arthritis
ivory phalanx = PsA
*also notice the fluffy periostitis, which can be commonly seen in PsA
pencil in cup
PsA
Ivory phalanx
PsA
telescoping digit
PsA
Andersson lesion = spondylodiskitis in AS pt (8% of AS pts)
Differential?
Symmetric sacroilitis = AS or IBD athropathy
(PAIR mnemonic, vowels are bilateral)
pencil in cup = PsA
What is an Andersson lesion?
seen in AS pseudarthrosis occuring in a completely ankylosed spine
CT demonstrates upper and mid zone fibrosis bilaterally with extensive bullous change. Syndesmophytes and vertebral body squaring are shown in the thoracic spine. There is some kyphosis.
“As little as 1% of ankylosing spondylitis patients have upper zone fibrosis on chest radiographs. The natural radiographic history is that of reticulonodular opacities becoming confluent. Bullae and cavitation is typical as in this case, therefore mimicking tuberculosis.”
Right septic arthritis. Don’t forget that UNILATERAL sacroiliac enhancement with central fluid collection extending to the psoas is most likely septic arthritis
Common distribution of psoriatic arthritis vs reactive arthritis
PsA: hands Reactive: feet
Secondary achilles tendinitis and thickening of soft tissues
Reactive arthritis
Symmetric sacroilitis differential
Ankylosing spondylitis IBD arthropathy Mnemonic for sacroilitis: “PAIR” Psoriatic arhtritis Ankylosing spondylitis IBD arthropathy Reactive arthritis Consonants are asymmetric Vowels are symmetric
Site reactive arthritis likes in the feet
calcaneus at retrocalcaneal bursa (commonly will have secondary Achilles tendinitis)
Unilateral sacroilitis
1 consideration: septic arthritis Psoriatic arthritis Reactive arthritis
plantar calcaneal spur with periosteal rxn
PsA and Reactie arthritis
Non MSK findings in AS
- pulmonary fibrosis (upper lung predominant)
- aortitis
- cardiac conduction defects
