Seven cases of calcium pyrophosphate crystal-induced arthritis are reported. All the patients were in the eighth or ninth decade of life. The clinical presentation in several was similar to and initially misdiagnosed as acute septic arthritis. All cases had the characteristic roentgenographic changes of chondrocalcinosis. Arthrocentesis and joint fluid analysis utilizing polarized light microscopy revealed calcium pyrophosphate crystals in six cases.
Angevine CD, Jacox RF. Pseudogout in the Elderly. Arch Intern Med. 1973;131(5):693-696. doi:10.1001/archinte.1973.00320110077011