CASE REPORT

A 53 year old woman presented to the rheumatology department in November 1988 with polyarthralgia, Raynaud’s phenomenon, proximal weakness, and high creatine kinase. Muscle biopsy confirmed an inflammatory myopathy. Treatment was started with high dose corticosteroids and azathioprine. During the next 10 years her myositis was persistently active and her disease modifying treatment was changed to oral methotrexate, and then a combination of oral cyclosporin and intramuscular methotrexate. She continued receiving doses of prednisolone above 10 mg.

In May 1998 she developed a tense effusion of her right knee. Several synovial aspirates were negative for culture and crystals (mycobacterium was not tested for at this stage). Synovial microscopy showed ++ polymorphs (range 0 to +++, quantitative leucocyte counts were not performed) and no red blood cells. Her C reactive protein became raised at 39 mg/l and her blood neutrophil count was 18×10⁹/l. Plain radiography showed mild degenerative changes only. Ultrasound confirmed a knee effusion, which communicated with her prepatella bursa. At this time her muscle disease was in remission. For the next two years her knee remained intermittently swollen with fluctuating high C reactive protein and neutrophil counts. …