Chapter

Investigations of calcium pyrophosphate deposition

Abhishek Abhishek and Michael Doherty

in Oxford Textbook of Osteoarthritis and Crystal Arthropathy

Third edition

Published on behalf of Oxford University Press

Published in print October 2016 | ISBN: 9780199668847
Published online November 2016 | e-ISBN: 9780191807176 | DOI: https://dx.doi.org/10.1093/med/9780199668847.003.0051

Series: Oxford Textbooks in Rheumatology

Investigations of calcium pyrophosphate deposition

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Joint aspiration and microscopic examination of the aspirated synovial fluid remains the gold standard for the diagnosis of calcium pyrophosphate crystal deposition (CPPD). If synovial fluid aspiration is not feasible, plain radiography and/or ultrasound scanning may be used to detect chondrocalcinosis (CC) which predominantly occurs due to calcium pyrophosphate (CPP) crystals, and this can be used as a diagnostic surrogate for CPPD as suggested by the EULAR Task Force. Acute CPP crystal arthritis often associates with a brisk acute phase response (elevated C-reactive protein (CRP) and/or erythrocyte sedimentation rate (ESR), plasma viscosity) and neutrophilia. A mildly raised CRP and/or ESR may be present in chronic CPP crystal inflammatory arthritis. On the contrary, asymptomatic CC, or CPPD with osteoarthritis does not cause raised acute phase reactants. As CPPD most commonly occurs due to increasing age and osteoarthritis, investigations to screen for underlying metabolic abnormalities should be carried out in those with early-onset CPPD (under 55 years), or in those with florid polyarticular CC. As hyperparathyroidism gets more common with ageing its presence should be specifically sought in all age groups. Tests for other predisposing metabolic conditions should only be carried out in the presence of specific clinical features. Genotyping for mutations, especially in the ANKH gene, may be warranted in those with a family history of premature CPPD and no evidence of inherited metabolic predisposition, but such testing is unavailable to most clinicians.

Chapter.  3311 words.  Illustrated.

Subjects: Rheumatology

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