Monoclonal gammopathies presenting as inflammatory arthritis: uncommon but important--a case series

To review the clinical profile of patients with plasma cell dyscrasias presenting with inflammatory arthritis.

Retrospective analysis was performed on clinical, laboratory and imaging data of patients who presented with inflammatory arthritis between May 2009 and April 2010 and were subsequently diagnosed as having plasma cell dyscrasias. Six out of 630 patients presenting with inflammatory arthritis were identified. The demographic, clinical and laboratory characteristics of these patients were analyzed. The diagnosis of monoclonal gammopathy was based on protein electrophoresis, immunoelectrophoresis and bone marrow biopsy. The outcomes of the treatments were analyzed.

Four patients had monoclonal gammopathy of unknown significance and two patients had multiple myeloma. Mean age of the patients was 65 years (range 59-74). Three patients presented with oligoarticular arthritis, two with symmetrical polyarticular joint pains and one with fleeting periarticular pains. Wrist and shoulder were the most commonly involved joints. Three patients had carpal tunnel syndrome. Five patients were seronegative for both rheumatoid factor and anti-cyclic citrullinated peptide antibodies. Mean erythrocyte sedimentation rate (ESR) was high in all patients (range: 82-120 mm/h with a mean of 99.6 mm/h). Arthritis improved with chemotherapy in patients with multiple myeloma.

Occurrence of inflammatory arthritis with plasma dyscrasias is more than a chance association. Plasma cell dyscrasias should be ruled out in any elderly patient presenting with atypical arthritis with disproportionately high ESR, high creatinine and hyperglobulinemia.