What is calcium pyrophosphate dihydrate?
Calcium pyrophosphate dihydrate is a calcium salt (Ca 2 P 2 O 2 ·2H 2 O) that in crystalline form (called CPP crystals) is deposited in cartilage and other articular tissues, leading to a variety of clinical manifestations.
CPPD is the preferred umbrella term for all presentations related to CPP crystal deposition. Other terms such as CPPDD/CPDD (calcium pyrophosphate dihydrate deposition disease) are the same as CPPD.