Calcium crystal-associated arthropathy (pseudogout) in a dog.

Calcium pyrophosphate dihydrate (Ca2P2O7.2H2O) crystal-associated arthropathy (pseudogout) was diagnosed in a dog. Clinical signs included non-weightbearing lameness, signs of pain on joint manipulation, and high rectal temperature. Arthrocentesis of carpal joints revealed extra- and intracellular crystals containing calcium. The suspected cause was polyarthritis secondary to chronic Ehrlichia infection. Results of joint tap performed after resolution of the clinical signs were negative for calcium pyrophosphate dihydrate crystals.