Seronegative spondyloarthropathies

Question 1

Seronegative spondyloarthropathy defined by negative _____________ and positive ___________

Answer 1

negative rheumatoid factor positive HLA-B27

Question 2

Answer 2

shiny corner = healing (sclerotic) romanus lesion

Question 3

Answer 3

Dagger spine in AS is due to ossificatio of the supraspinous and interspinous ligaments

Question 4

What is a romanus lesion?

Answer 4

seen in AS erosions of the anterior superior or inferior edges of the vertebral body endplates caused by enthesitis

Question 5

What is a shiny corner?

Answer 5

seen in AS represents sclerosis of prior Romanus lesions at the corners of the vertebral bodies

Question 6

Patterns of PsA:

Answer 6

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

Question 7

Sequela of infectious diarrhea, urethritis, or cervicitis

Answer 7

Reactive arthritis (Reiter’s)

Question 8

Sausage digit

Answer 8

PsA

Question 9

Answer 9

pencil in cup = PsA

Question 10

Do erosions in seronegative spondyloarthropaties affect the ischial or iliac aspect of the SI joint?

Answer 10

iliac aspect of the join

Question 11

Answer 11

Telescoping digits in PsA. Arthritis mutilans

Question 12

main-en-lorgnette

Answer 12

PsA (and Rheumatoid Arthritis)

Question 13

Answer 13

large lateral osteophytes is associated with PsA

Question 14

Answer 14

bamboo spine in AS

Question 15

Bulky lateral bony outgrowths

Answer 15

PsA and Reactive arthritis

Question 16

Answer 16

ivory phalanx = PsA

Question 17

Asymmetric sacroilitis differential

Answer 17

• Psoriatic arthritis
• Reactive arthritis

Mnemonic for sacroilitis:

“PAIR”

• Psoriatic arhtritis
• Ankylosing spondylitis
• IBD arthropathy
• Reactive arthritis

Consonants are asymmetric Vowels are symmetric

Question 18

Answer 18

Reactive arthritis

Question 19

Answer 19

main-en-lorgnette (opera glass hand) in PsA

Question 20

Answer 20

erosion at retrocalcaneal bursa - seen in inflammatory arthropathies but most commonly associated with REACTIVE arthritis/”reiter’s”

Question 21

Answer 21

IBD sacroilitis. Notice the lead pipe deformity of the bowel (red arrow) and bilateral symmetric sacroilitis.

Question 22

What are the four seronegative spondyloarthropathies

Answer 22

Ankylosing spondylitis Psoriatic arthritis Reactive arthritis (Reiter’s) Inflammatory bowel disease associated arthropathy

Question 23

What portion of the SI joints are affected in seronegative spondyloarthropathies?

Answer 23

inferior aspect since this portion is a synovial (diarthrodial) joint

Question 24

Answer 24

Romanus lesions (erosions at the superior anterior endplate) seen in seroneg spondyloarthropathies like AS and IBD arhtropathy

Question 25

Spine signs in AS

Answer 25

* **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

Question 26

Seronegative spondyloarthropathy that commonly affects the feet

Answer 26

reactive arthritis (previously Reiter disease)

Question 27

Fluffy periostitis

Answer 27

psoriatic arthritis

Question 28

Question 29

Answer 29

ivory phalanx = PsA \*also notice the fluffy periostitis, which can be commonly seen in PsA

Question 30

pencil in cup

Answer 30

PsA

Question 31

Ivory phalanx

Answer 31

PsA

Question 32

telescoping digit

Answer 32

PsA

Question 33

Answer 33

[Andersson lesion](https://radiopaedia.org/articles/andersson-lesion-1?lang=us) = spondylodiskitis in AS pt (8% of AS pts)

Question 34

Differential?

Answer 34

Symmetric sacroilitis = AS or IBD athropathy ([PAIR mnemonic](https://radiopaedia.org/articles/sacroiliitis-differential?lang=us), vowels are bilateral)

Question 35

Answer 35

pencil in cup = PsA

Question 36

What is an Andersson lesion?

Answer 36

seen in AS pseudarthrosis occuring in a completely ankylosed spine

Question 37

Answer 37

[Pulmonary fibrosis in AS](https://radiopaedia.org/cases/pulmonary-fibrosis-in-ankylosing-spondylitis?lang=us) 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."

Question 38

Answer 38

Right septic arthritis. Don't forget that UNILATERAL sacroiliac enhancement with central fluid collection extending to the psoas is most likely septic arthritis

Question 39

Common distribution of psoriatic arthritis vs reactive arthritis

Answer 39

PsA: hands Reactive: feet

Question 40

Secondary achilles tendinitis and thickening of soft tissues

Answer 40

Reactive arthritis

Question 41

Symmetric sacroilitis differential

Answer 41

Ankylosing spondylitis IBD arthropathy Mnemonic for sacroilitis: "PAIR" Psoriatic arhtritis Ankylosing spondylitis IBD arthropathy Reactive arthritis Consonants are asymmetric Vowels are symmetric

Question 42

Site reactive arthritis likes in the feet

Answer 42

calcaneus at retrocalcaneal bursa (commonly will have secondary Achilles tendinitis)

Question 43

Unilateral sacroilitis

Answer 43

#1 consideration: septic arthritis Psoriatic arthritis Reactive arthritis

Question 44

Answer 44

Question 45

plantar calcaneal spur with periosteal rxn

Answer 45

PsA and Reactie arthritis

Question 46

Non MSK findings in AS

Answer 46

* pulmonary fibrosis (upper lung predominant) * aortitis * cardiac conduction defects