Update in calcium deposition diseases.
OBJECTIVE
Calcium pyrophosphate dihydrate and basic calcium phosphate crystals are common components of osteoarthritic synovial fluids and define subsets of patients with inflammatory or rapidly destructive arthritis. Recent literature concerning clinical and etiologic aspects of calcium pyrophosphate dihydrate and basic calcium phosphate crystal arthritis are reviewed.


RESULTS
Recent literature reminds us of the propensity of calcium pyrophosphate dihydrate deposition disease to mimic other syndromes affecting the elderly. Several new studies reinforce the prevalence and significance of extra-articular calcium pyrophosphate dihydrate deposits, and demonstrate the presence of basic calcium phosphate-like whitlockite crystals in intervertebral discs. Current work serves to increase our appreciation for the complex role of the putative pyrophosphate transporter, ANKH, in healthy and diseased cartilage. The application of newer radiographic techniques to the diagnosis of calcium pyrophosphate dihydrate deposition disease holds promise for easier and more accurate identification of these crystal deposits in vivo. Work demonstrating the efficacy of a crystal poison in an animal model of osteoarthritis provides good evidence for a pathogenic role of calcium crystals in osteoarthritis, and hope for new therapies for these diseases.


CONCLUSIONS
Continued work will further our understanding of these common crystals and their associated clinical syndromes.
Rosenthal
Ann K
AK
Medical College of Wisconsin, Zablocki VA Medical Center, Milwaukee, Wisconsin 53295-1000, USA. ann.rosenthal@med.va.gov
D001168:Arthritis / Q000209:etiology; D002131:Calcium Pyrophosphate / Q000378:metabolism*; D002805:Chondrocalcinosis / Q000175:diagnosis / Q000276:immunology / Q000503:physiopathology*; D006801:Humans; D028061:Phosphate Transport Proteins
C498770:ANKH protein, human; D028061:Phosphate Transport Proteins; D002131:Calcium Pyrophosphate