Answer to question of the day – symmetrical arthritis

The answer is…. b. Rheumatoid arthritis

Symmetrical disease?
Erosions?
This is classical of RA X-ray changes that include

1. Erosions
2. Reduced joint space
3. Peri-articular osteoporosis
4. Nodules

So from the initial history of disease [small joints, both hands], the likely diagnoses would be

  • RA
  • PsA
  • (less likely) gout.

Erosive changes are not specific to RA however but the findings were symmetrical

  • both gout and PsA tend to be asymmetrical

Don’t be put off by the fact he’s male, although RA is roughly 3x commoner in women. You dont get a mention of which joints are affected here: RA has a penchant for the wrists and MCP joints. Erosions of the ulnar styloid are very common.

Common x-ray changes of the different arthritides are shown below:

Non Inflammatory

Primary OA: Asymmetrical

There are classically 4 signs of OA on an X-ray: Occurs in classic joints eight bearing e.g. Hips& Knees. May not be symmetrical.

1. Subchondral bone sclerosis
2. Cystic Change
3. Osteophytes
4. Reduced Joint Space

Charcot Joints:

1. Destruction of the joint
2. Disorganisation (bones not arranged in the correct /usual arrangement through gross destruction e.g. cuniforms of the foot.
3. Increased density (sclerosis)
4. Debris (boney debris from a destroyed joint: often with well defined margins
5. Dislocation

Secondary OA

As per primary OA but occurring in a joint that has been previously damaged from any other disease process (inflammatory disease etc)

Inflammatory

Gout: Asymmetrical

The classical signs of gout on an Xray are: Erosions with sclerotic margins. Asymmetrical.

1. A relatively preserved joint space
2. Minimal periarticular osteoporosis
3. Nodules (these are in fact tophi)

Psoriatic Arthritis: Asymmetrical

The X-ray Changes are similar to rheumatoid but they differ in their distribution, and the formation of pencil in cup deformities along with osteolysis.

1. Asymmetrical distribution of disease
2. Often affects PIP and DIP joints
3. relative absence of peri-articular osteoporosis
4. Erosions seen at the distal interphalangeal joints joints
5. Reduced joint space
6. Pencil in cup deformity (arthritis mutilans with telescoping of the fingers)- this is a result of osteolysis
7. Loss of the terminal tufts of the phalanges (acro-osteolysis)
8. Sacroiliac and spondylitic changes (similar to those of Ank. Spond.)

Rheumatoid Arthritis: Symmetrical

1. Erosions
2. Reduced joint space
3. Periarticular osteoporosis
4. Nodules

Septic Arthritis: Asymmetrical

1. Periarticular osteoporosis
2. Loss of joint space
3. Deformity/subluxation
4. Erosions
5. Effusion
6. Usually just 1 joint

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