title: Rheumatoid arthritis and pseudo-rheumatoid arthritis in calcium pyrophosphate dihydrate crystal deposition disease.
abstract: Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease can lead to many clinical syndromes. One syndrome simulates rheumatoid arthritis and is thus called "pseudo-rheumatoid arthritis." Since some patients have true rheumatoid arthritis with CPPD crystal deposition disease, the clinician may have difficulty differentiating those patients from others who have the pseudo-rheumatoid syndrome. Such a diagnostic problem can be solved radiographically. Eleven patients with CPPD crystal deposition disease were studied; five had true rheumatoid arthritis and six had pseudo-rheumatoid arthritis. Because osseous erosions were not apparent in the arthropathy of uncomplicated CPPD crystal deposition disease, the detection of skeletal erosive changes indicated a true rheumatoid arthritis process.
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000000981:diagnostic imaging*; D002131:Calcium Pyrophosphate / Q000032:analysis*; D002805:Chondrocalcinosis / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D011756:Diphosphates / Q000032:analysis*; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011859:Radiography
chemical_list: D011756:Diphosphates; D002131:Calcium Pyrophosphate