Ch.23 - Recognizing Joint Disease: An Approach to Arthritis

Question 1

Arthritides can be roughly divided into:

Answer 1

1. Hypertrophic.
2. Infectious.
3. Erosive (inflammatory categories).

Question 2

Hypertrophic arthritis:

Answer 2

1. Subchondral sclerosis.
2. Marginal osteophyte production.
3. Subchondral cyst formation.

Question 3

MC form of arthritis:

Answer 3

Primary osteoarthritis.

Question 4

Primary osteoarthritis:

Answer 4

A type of hypertrophic arthritis.
–> Typically occurs on weight-bearing surfaces of the hip and knee and the distal interphalangeal joints of the fingers.

Question 5

Other hypertrophic arthritides include:

Answer 5

1. CPPD.
2. Charcot joints.
3. Osteoarthritis 2o to prior trauma, AVN, or superimposed on another underlying arthritis.

Question 6

Pyrophosphate arthropathy (CPPD):

Answer 6

Occurs with the deposition of calcium pyrophosphate crystals (chondrocalcinosis).
–> It can produce multiple subchondral cysts, narrowing of the patellofemoral joint space, metacarpal hooks, promixal migration of the distal carpal row.

Question 7

Charcot or neuropathic joints:

Answer 7

1. Fragmentation.
2. Sclerosis.
3. Soft tissue swelling.
4. Diabetes is the most frequent cause of a Charcot joint.

Question 8

Erosive (or inflammatory) arthritis:

Answer 8

Associated with inflammation and synovial proliferation (pannus formation) which produces lytic lesions in or near the joint called erosions.

Question 9

3 examples of erosive arthritis:

Answer 9

1. RA.
2. Psoriatic.
3. Gout.
   Site of involvement is helpful in differentiating among the causes of erosive arthritides.

Question 10

RA:

Answer 10

Affects the carpals and proximal joints of the hands, can widen the predentate space in the cervical spine, and produces fusion of the posterior elements in the cervical spine.

Question 11

Gout:

Answer 11

Most often affects the metatarsal-phalangeal joint of the great toe with juxta-articular erosions and little or no osteoporosis.
–> Tophi are late manifestations of the disease and usually do not calcify.

Question 12

Psoriatic arthritis:

Answer 12

Usually occurs in patients with known skin changes and affects the distal joints primarily in the hands producing characteristic erosions that resemble a pencil in cup.

Question 13

Ankylosing spondylitis:

Answer 13

A chronic/progressive arthritis characterized by symmetric fusion of the SI joints and ASCENDING involvement of the spine –> Bamboo-spine appearance.

Question 14

Infectious arthritis:

Answer 14

Soft tissue swelling and osteopenia –> In case of pyogenic arthritis, relatively early and marked destruction of most or all of the articular cortex.
–> Mostly due to staph and gonococcal organisms.

Question 15

An arthritis is a disease of a …

Answer 15

Joint that invariably leads to JOINT SPACE NARROWING and changes to the bones on BOTH sides of the joint.

Question 16

Hypertrophic arthritis is characterized by bone formation …?

Answer 16

Either WITHIN the confines of preexisting bone (subchondral sclerosis) OR by bony protrusions extending from the normal bone (osteophytes).

Question 17

Hypertrophic arthritides include:

Answer 17

1. Osteoarthritis (1o and 2o).
2. Erosive osteoarthritis.
3. Charcot arthropathy (neuropathic joint).
4. CPPD.

Question 18

The 4 imaging findings of osteoarthritis:

Answer 18

1. Marginal osteophyte formation –> HALLMARK.
2. Subchondral sclerosis.
3. Subchondral cysts.
4. Narrowing of the joint space.

Question 19

Arthritides usually diagnosed radiologically?

Answer 19

1. OA.
2. Early RA.
3. CPPD.
4. AS.
5. TB.
6. Charcot joint - late.

Question 20

Arthritides usually diagnosed clinically?

Answer 20

1. Septic (pyogenic).
2. PA.
3. Gout.
4. Hemophilia.

Question 21

Radiographic findings of 2o OA are the same as those for the primary form with several special clues to help suggest 2o OA:

Answer 21

1. Atypical AGE for 1o OA (20-yr old).
2. Atypical appearance for 1o OA - not symmetrical.
3. Unusual location for 1o OA - The elbow joint.

Question 22

2o OA is usually due to …?

Answer 22

Trauma that damages or leads to damage of the articular cartilage.

Question 23

Mention some causes of 2o OA (5):

Answer 23

1. Trauma.
2. Infection.
3. AVN.
4. CPPD.
5. RA.

Question 24

Erosive OA is a type of …?

Answer 24

PRIMARY OA characterized by more SEVERE INFLAMMATION and by the development of erosive changes.

Question 25

Erosive OA occurs most often in …?

Answer 25

Perimenopausal females.

Question 26

Erosive OA - Findings:

Answer 26

Bilaterally symmetrical changes such as the osteophytes or primary OA with marked inflammation (swelling and tenderness) + erosions at the affected joints.

Question 27

Erosive OA - The erosions are typically …?

Answer 27

CENTRALLY located within the joint and, combined with the small osteophytes –> Gull-wing deformity.

Question 28

Erosive OA most commonly occurs at the …?

Answer 28

1. Proximal and distal interphalangeal joints of the fingers.
2. 1st carpal-metacarpal + the interphalangeal joint of the thumb.

Question 29

What uncommon finding in primary OA may occur in erosive OA?

Answer 29

BONY ANKYLOSIS.

Question 30

Causes of Charcot joint by location - Shoulder:

Answer 30

1. Syrinx.
2. Spinal tumor.
3. Syphilis.

Question 31

Causes of Charcot joint by location - Hips:

Answer 31

1. Tertiary syphilis.

2. Diabetes.

Question 32

Causes of Charcot joint by location - Ankles/Feet?

Answer 32

1. Diabetes (common).

2. Syphilis (uncommon).

Question 33

As a hypertrophic arthritis, Charcot joint will demonstrate …?

Answer 33

EXTENSIVE SUBCHONDRAL SCLEROSIS.

Question 34

Diagnostic problem with Charcot joint?

Answer 34

Shares findings with osteomyelitis.

–> Both produce bone destruction + periosteal reaction (from fracture healing).

Question 35

How to differentiate between Charcot and osteomyelitis?

Answer 35

A radioactive Indium-tagged white-cell bone scan can help to differentiate infection from Charcot joint.

Question 36

Pyrophosphate arthropathy may be indistinguishable from primary OA but differs from it in several important respects:

Answer 36

1. CPPD affects joints not usually affected by primary OA such as the patellofemoral joint space of the knee + the radiocarpal joint + the wrist joints.
2. Chondrocalcinosis is usually present in pyrophosphate arthropathy.
3. Subchondral cysts are more common, larger, more nuremous and more widespread than in primary OA.
4. Hook-shaped bony excrescences along the 2nd and 3rd metacarpal heads - common in CPPD.

Question 37

What is the study of first choice in RA?

Answer 37

Conventional radiographs.

Question 38

Earliest radiographic findings of RA:

Answer 38

1. Soft tissue swelling of the affected joints.

2. Osteoporosis –> Periarticular osteroporosis or periarticular demineralization.