Arthritis

Question 1

Most common sites of OA in the hand

Answer 1

DIP > 1st CMC > PIP

Question 2

Underlying etiology of Heberden or Bouchard nodes

Answer 2

Large osteophytes cause local soft tissue swelling

Question 3

Location of:

1. Heberden nodes
2. Bouchard nodes

Answer 3

1. DIP
2. PIP

Question 4

Typical distribution of erosive OA

Answer 4

DIPs in the hands

Question 5

Classic imaging finding in erosive OA

Answer 5

Gull-wing deformity

• central erosions
• marginal osteophytes

Question 6

Most common sites of OA in the foot

Answer 6

1st MTP > talonavicular joint (dorsal beaking)

Question 7

Migration pattern of the femoral head in OA of the hips

Answer 7

Superolateral > medial

Question 8

Migration pattern of the femoral head in RA of the hips

Answer 8

Axial

Question 9

Most likely diagnosis:

• axial migration of femoral head
• osteophytes present

Answer 9

Osteoarthritis

(very rare migration pattern)

Question 10

What does gas within the vertebral body compression fracture indicate?

Answer 10

Avascular necrosis

(also called Kummel disease)

Question 11

What ligament is often ossified in DISH?

Answer 11

Posterior longitudinal (PLL)

Question 12

Diagnostic criteria of DISH:

• flowing bridging anterior osteophytes ≥ 4 levels
• ?

Answer 12

Normal disc spaces and sacroiliac joints

Question 13

Most common initial areas affected by RA

Answer 13

Small joints in the hands, wrist and foot

Question 14

Pathogenesis and pathologic hallmarks of RA

Answer 14

• RF = antibodies against IgG
• waxing/waning activation of complement cascade
• cycles of repeated synovial inflammation
• marginal erosions and periarticular osteopenia

Question 15

Most common large joints affected by RA

Answer 15

Knees, hips, shoulders and cervical spine

Question 16

Radiographic features of RA

Answer 16

• marginal erosions
• periarticular osteopenia
• soft tissue swelling
• symmetric joint space narrowing
• joint subluxations

Question 17

Most common affected joints in the hand with RA

Answer 17

MCP > PIP > carpals

Question 18

Most common location of initial erosions in RA of the hand

Answer 18

• radial aspect of the 2nd and 3rd metacarpal heads
• radial and ulnar aspects of the phalangeal bases
• ulnar styloid

Question 19

Classic subluxation deformities in RA

(3)

Answer 19

• Boutonierre (PIP flexed, DIP extended)
• Swan neck (DIP flexed, PIP extended)
• Ulnar subluxation at the MCPs

Question 20

Late-stage finding in the wrist that is rare in RA but common in JIA

Answer 20

Carpal ankylosis

Question 21

Most common location of RA in the feet

Answer 21

MTP joints

Question 22

Pathologic endpoint of RA in the hips

Answer 22

Concentric acetabular degeneration → axial migration → protrusio deformity

Question 23

Diagnostic criteria of protrusio deformity

Answer 23

• males → > 3 mm
• females → > 6 mm

(medial to the ilioischial line)

Question 24

Which joint is least commonly affected by erosions in RA?

Answer 24

Knees

Question 25

Type of cervical subluxation that occurs in RA with transverse ligament erosion

Answer 25

Anterior * most common * especially prominent with flexion

Question 26

Type of cervical subluxation that occurs in RA with facet joint erosion

Answer 26

Vertical impaction * protrusion of dens through foramen magnum * compression of midbrain

Question 27

Type of cervical subluxation that occurs in RA with odontoid erosion

Answer 27

Posterior subluxation

Question 28

Anterior atlanto-axial subluxation is present if the interval is...

Answer 28

* \> 3 mm (in adults) * \> 5 mm (in children)

Question 29

Name the 4 inflammatory (seronegative) spondyloarthropathies

Answer 29

1. Ankylosing spondylitis 2. Psoriatic arthritis 3. Reactive arthritis 4. IBD-associated arthritis * by definition, negative for RF * associated with HLA-B27

Question 30

Feature common to all of the inflammatory arthropathies

Answer 30

Sacroiliitis * usually only affects the inferior portion * erosions often affect the iliac aspect first

Question 31

Inflammatory arthropathies that cause symmetric sacroiliitis (vowels)

Answer 31

* Ankylosing spondylitis * IBD-associated arthritis

Question 32

Inflammatory arthropathies that cause asymmetric sacroiliitis (consonants)

Answer 32

* Psoriatic arthritis * Reactive arthritis

Question 33

Major differential diagnosis for unilateral sacroiliitis

Answer 33

Septic arthritis

Question 34

Earliest radiographic signs of ankylosing spondylitis

Answer 34

Symmetric erosions, widening and sclerosis of the SI joints

Question 35

Extra-skeletal conditions associated with ankylosing spondylitis

Answer 35

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

Question 36

How does ankylosing spondylitis progress through the spine?

Answer 36

Ascends from lumbar to cervical spine

Question 37

Initial pathologic feature of ankylosing spondylitis in the spine

Answer 37

Romanus lesions * erosions of the anterior superior/inferior endplate edges * caused by enthesitis at the attachment site of the disc

Question 38

Following Romanus lesions, how does ankylosing spondylitis progress throughout the spine?

Answer 38

Romanus lesions → shiny corners → squaring of corners → syndesmophytes * shiny corners represent sclerosis of Romanus lesions

Question 39

Complication of long-standing anklyosing spondylitis that can mimic osteomyelitis

Answer 39

Andersson lesion * aka spinal psuedoarthrosis (false functional joint) * destructive lesion through the disc-plate complex * only occurs in an area that is completely ankylosed

Question 40

Most common location for psoriatic arthritis

Answer 40

Hands * no periarticular osteopenia (unlike RA) * precedes skin manifestations in ~ 20% of cases

Question 41

Radiographic features of psoriatic arthritis in the hand

Answer 41

* sausage digit * pencil-in-cup deformity (usually DIP) * fluffy periostitis * marginal erosions

Question 42

Radiographic hallmark of arthritis mutilans of the hand (end-stage psoriatic arthritis)

Answer 42

Telescoping digit

Question 43

Most common locations for psoriatic arthritis in the feet

Answer 43

* IP joint of the great toe * MTP joints

Question 44

Radiographic features of psoriatic arthritis in the feet

Answer 44

* ivory phalanx (osteosclerosis) * plantar calcaneal spur with periosteal reaction

Question 45

Radiographic hallmark of psoriatic arthritis in the spine

Answer 45

Bulky lateral outgrowths with bony bridging

Question 46

While psoriatic arthritis usually affects the hands, reactive arthritis usually affects...

Answer 46

...the feet * but otherwise has similar radiographic findings