How do you decide on initiation of treatment with steroids or immunomodulatory therapy in patients with statin-induced myopathy versus statin-induced autoimmune necrotizing myopathy?

In the setting of limited experience, in patients with statin induced necrotizing polymyositis (HMG-CoA reductase antibody mediated necrotizing myositis), the best approach is typically steroids (prednisone 20mg or so), IViG 2gm/kg every 4 weeks, and potentially CellCept at 2000 to 3000mg per day, w...

In the setting of a hospitalized patient with rhabdomyolysis, the differential between statin toxicity and statin-associated IMNM can be difficult. All diagnostic modalities (muscle biopsy, EMG, muscle MRI) in the acute setting cannot discriminate, so we can only rely on the antibody. Fortunately, t...

If the patient has apparent muscle weakness, I give IVIG until the HmG- COA antibody result is back. I avoid steroids as they can be detrimental if it is only rhabdomyolysis.