Symptoms of calcific periarthritis
Typical presentation of periarticular calcium deposits (calcific periarthritis)
BCP deposition is common in the shoulder, most commonly involving the rotator cuff tendons. Multiple areas of deposition are common and 50% of cases are bilateral. Calcific periarthritis affects predominantly middle-aged women, most often on the dominant side. The supraspinatus tendon is most commonly involved followed by infraspinatus and subscapularis. Symptoms can range from asymptomatic to chronic smoldering pain to acute episodes of severe pain due to acute inflammation. Longstanding calcification can lead to adhesive capsulitis and sometimes tendon tears. Tendons around other joints may also be affected, including the hand, wrist, hip, knee, foot, and neck (longissimus colli muscle at insertion into the anterior tubercle of the atlas).
On radiographs, the calcific deposits can be dense and globular particularly when asymptomatic, or fragmented and fluffy in the setting of acute inflammation. Synovial fluid examination typically reveals <1000 cells/mL 3 . BCP crystals are not visible on regular light or polarizing microscopy due to their small size (20–100 nm) and lack of birefringence. Although clumps of BCP crystals can be seen with alizarin red staining, this is not specific for BCP crystals and CPP crystals will also stain positive.
