Basic Calcium Phosphate (BCP) Diseases
Diseases associated with BCP crystals:
- Calcific periarthritis
- Calcific deposits in tendons, bursae, joint capsules
- Acute calcific periarthritis
- BCP arthropathy
- Acute synovitis
- Destructive arthropathy
- Subcutaneous/soft tissue calcifications
- Connective tissue diseases: systemic lupus erythematosus, systemic sclerosis, mixed connective tissue disease, dermatomyosits
- Metastatic calcifications: chronic renal failure with high calcium–phosphorus product (>70)
- Tumoral calcinosis
BCP deposition is common in the shoulder. Up to 5% of shoulder roentgenograms in adults have periarticular calcium deposits, usually in the supraspinatus tendon. These deposits can be asymptomatic or cause pain and impingement. Tendons around other joints may also be affected, including the hand, wrist, hip, knee, foot, and neck (longissimus colli muscle at its insertion into the anterior tubercle of the atlas). Radiographically the calcific deposits can be dense and globular when asymptomatic or fragmented and fluffy due to the effects of inflammation.
Acute calcific periarthritis:
When BCP crystals are shed from a calcific deposit, there is an intense local inflammatory reaction to the crystals, similar to other crystalline arthritides. If this reaction occurs around a joint, the clinical picture is an acute arthritis with pain, warmth, loss of motion, and swelling. Roentgenograms reveal the BCP deposit and thus identify the crystal causing the problem. Acute calcific periarthritis most commonly occurs in the shoulder from calcifications in the supraspinatus tendon. Attacks of calcific periarthritis can occur in other joint areas either spontaneously or after minor trauma.