The Purpose of the report was introducing rheumatoid arthritis in a dog in Iran. A four-year-old castrated male shih tzu has been referred to Small Animal Hospital. History taking, clinical findings, laboratory findings, radiography, computed tomography scan (CT-Scan) and magnetic resonance imaging (MRI) carried out in this case. Clinical examinations revealed severe lameness with flexion of stifle joints and muscular atrophy of thigh region. Survey radiographs showed tibial and femoral subchondral bone cyst-like formation, cranial displacement of the tibia, and asymmetric joint space. Blood test revealed leukocytosis. In serology, rheumatoid factor (RF) and antinuclear antibodies (ANA) were negative. Arthrocentesis of affected joints showed a lowered viscosity, and was turbid. CT-Scan studies showed subchondral bone cyst-like formations on the tibial plateau and femoral condyles, osteophyte formations, and degenerative joint changes. MRI confirmed soft tissue changes of the joint component. Based on clinical and paraclinical findings, diagnosis was rheumatoid arthritis.
J.Fac. Vet. Med. Univ.Tehran. 60,1:95-96,2005.
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