7yrs on prednisone & methotrexate + for "resistant ra" recent elevated jo1, histone, muscle pain. how to confirm if polymyositis w/o stopping meds?

Both drugs work both: Both drugs are effective in polymyositis. Your jo-1 could be specious so you need evidence for muscle inflammation.A serum CPK and myoglobin would best reflect the activity of a "myositis, " should one exist. Also, if you have ra, your ccp antibody is positive 98% of the trime. Finally, some patients have two diseases, always a possibility.

See below: The diagnosis of polymyositis would be based iniatilly on the presence of weakness paricularly proximal muscles. The next step would be to check blood tests for muscle inflammation including a CPK and aldolase. If thoes are abnormal the next step is a nerve and muscle test called an emg/ncv. If that is abnormal the most definitive test is a muscle biopsy so a jo-1 would not make the diagnosis.

Mucle testing: Inflammatory myopathy, including polymyositis, is best diagnosed and treated by a trained rheumatologist. Symptoms are proximal muscle weakness. Abnormal lab tests include elevated muscle enzymes (CPK, AST/ALT); positive antibody tests, including Jo-1; abnormal EMG/nerve conduction test; edema seen on an MRI of proximal muscles; muscle biopsy showing destruction and regeneration of muscle cells.