- Precipitation of calcium pyrophosphate crystals
- Tendency to affect joints w/established OA/trauma
- Relatively uncommon (< 1/1000)
- Also assoc w/hyperparathyroidism, hypothyroid, hemochromatosis; often idiopathic
- Acute joint pain and inflammation
- Typically larger joints: knees, hips, shoulders, elbows, wrists, hands
- Can look like gout
- Often self limited
- Can be recurrent
- Effusion and pain w/movement of affected joint