under the microscope. However, even this method has poor sensitivity, specificity, and inter-operator agreement. These two modalities currently define CPPD disease, but lack diagnostic accuracy. Thus, the diagnosis of CPPD disease is potentially epiphenomenological. Treatment Because any medication that could reduce the inflammation of CPPD bears a risk of causing organ damage, treatment is not advised if the condition is not causing pain. For acute pseudogout, treatments include intra-articular corticosteroid injection, systemic corticosteroids, non-steroidal anti-inflammatory drugs (NSAIDs), or, on occasion, high-dose colchicine. In general, NSAIDs are administered in low doses to help prevent CPPD. However, if an acute attack is already occurring, higher doses are administered. If nothing else works, hydroxychloroquine or methotrexate may provide relief. Research into surgical removal of calcifications is underway, however, this still remains an experimental procedure. There is currently no treatment for non-invasive removal of these crystals, once they are deposited. Attempts to dissolve crystals in situ using enzymes turned up to be a "clinical failure". New, innovative methods using catalytic peptides are in development. Epidemiology The condition is more common in older adults. CPPD is estimated to affect 4% to 7% of the adult populations of Europe and the United States. Previous studies have overestimated the prevalence by simply estimating the prevalence of chondrocalcinosis, which is found in many other conditions as well. It may cause considerable pain, but it is never fatal. Women are at a slightly higher risk than men, with an estimated ratio of occurrence of 1.4:1. History CPPD crystal deposition disease was originally described over 50 years ago. Terminology Calcium pyrophosphate dihydrate crystals are associated with a range of clinical syndromes, which have been given various names, based upon which clinical symptoms or radiographic findings are most prominent. A task force of the European League Against Rheumatism (EULAR) made recommendations on preferred terminology. Accordingly, calcium pyrophosphate deposition (CPPD) is an umbrella term for the various clinical subsets, whose naming reflects an emphasis on particular features. For example, pseudogout refers to the acute symptoms of joint inflammation or synovitis: red, tender, and swollen joints that may resemble gouty arthritis (a similar condition in which monosodium urate crystals are deposited within the joints). Chondrocalcinosis, on the other hand, refers to the radiographic evidence of calcification in hyaline and/or fibrocartilage. "Osteoarthritis (OA) with CPPD" reflects a situation where osteoarthritis features are the most apparent. Pyrophosphate arthropathy refers to several of these situations. References