A case of differential diagnosis in a patient with hand OA

Abstract

Background: Hand osteoarthritis is mainly a primary osteoarthritis, involving genetic predisposition. Although clinical diagnostic criteria were developed and many cases can be diagnosed without additional diagnostic procedures, some patients need a comprehensive assessment to exclude other possible arthritis. Case report: Female patient A., 61 years old, presented with pain both at rest and during motion in wrists, first CMC (carpometacarpal), 2-3rd MCP (metacarpophalangeal) and first to Vth PIPs (proximal interphalangeal), as well as 2-3rd DIPs (distal interphalangeal) joints. Being asked the patient reported morning stiffness more than 30 minutes but less than one hour. She reported the symptoms having a gradual onset for the last year, however the complaints worsened in the last 2 months and as she reports the MCPs got swollen in the last months. Physical examination revealed no tenderness in the wrists, yet significant tenderness in both first CMCs, mildly tender MCPs on squeeze test, as well as tenderness and mild swelling in IIIII PIPs. At this moment considering morning stiffness, the reported joint swelling and the pattern of joint involvement, 3 main diagnoses should be considered: early onset RA, osteoarthritis of the hand and calcium pyrophosphate deposition disease. Laboratory assessments: Uric acid: 402 μmol/l; ALT:26.1 U/L; Anti HBcor sum (Anti HBcor sum:7.27 S/CO, Anti HBcor sum: Reactive ); Anti HCV (Anti HCV:0.08 S/CO, Anti HCV: Nonreactive ); ASL-O (Antistreptolizina-O):91 IU/ml; AST:31.7 U/L; Direct Billirubin:6.4 μmol/l; Total Billirubin:17.0 μmol/l; Calcium:2.68 mmol/l; Creatinine:58.0 μmol/l; Rheumatoid factor: 124.0 IU/ml; HBs Ag (HBs Ag:0.31 S/CO, HBs Ag :Nonreactive ); C-reactive protein: 5.56 mg/l; Uree:8.1 μmol/l; Fibrinogen: 4.0 g/l; anti CCP < 10 U/ml. X-ray revealed diffuse moderately expressed osteoporosis, signs of osteophyte formation in the PIPs, and asymmetric narrowing of the joint space, and subchondral bone sclerosis, advanced disarthrosis, capsular densifications on the capsule of the II and III MCPs. Conclusions: The final diagnosis was Hand osteoarthritis based on specific radiological findings and a clinical picture pleading more for a degenerative condition. Initially, before the definite development of Heberden’s and Bouchard’s nodes patients go through a stage of inflammation with mild joint swelling, which poses certain question in the initial diagnosis of hand osteoarthritis. The confounding laboratory data such as presence of Rheumatoid Factor and a mildly increased C-reactive protein may be explained by the depiction of positive Anti- Hbcore sum). Additionally the patient did not have anti-CCP antibodies which are more specific for RA.