How I treatInflammatory myopathies: how to treat the difficult cases
Section snippets
Summary
The initial approach to the treatment of patients with inflammatory myopathy is critical in determining the subsequent course and outcome. Prolonged administration of high doses of corticosteroids should be avoided and a second-line agent such as methotrexate or azathioprine should be introduced earlier rather than later. Intravenous immunoglobulin therapy has an important place if the myositis remains active, particularly in patients with dermatomyositis, and is the treatment of choice in
Initial treatment
It is important that the initial treatment regimen should be tailored to the individual patient. In most cases of DM or PM treatment is commenced with oral prednisolone in a dose of ∼1 mg/kg/day which is then continued for a period of 4–6 weeks before gradually tapering to a maintenance dose over the next 2–3 months. In patients with severe myositis, and when the diagnosis has been unduly delayed, we recommend starting treatment with a combination of prednisolone and methotrexate (10 mg/week)
Relapses
Relapses may occur during the dose reduction period, or more often in patients who are in remission on stable maintenance therapy or off treatment.[8], [9] Most relapses can be controlled by increasing the dose of prednisolone to ∼50 mg/day (∼0.7 mg/kg/day) for a further 4–6 week period and methotrexate (or azathioprine) should be continued or reintroduced as a steroid-sparing measure. In more severe relapses in patients who are already on corticosteroids and an immunosuppressive agent we
Steroid-resistant cases
If the response to prednisolone during the first 4–6 weeks is poor, or if steroid side-effects develop, methotrexate (or azathioprine) should be commenced and the dose of prednisolone gradually tapered. This will reduce the likelihood of inducing a steroid myopathy, and will often achieve control of the myositis. However, if there is persisting or increasing weakness and the serum CK level remains elevated it is worth trying a combination of methotrexate and azathioprine.10 In more severe
Corticosteroid myopathy
A steroid-induced myopathy should be suspected if there is persisting or increasing proximal weakness, particularly in the lower limbs, after the serum CK level has returned to normal. Steroid myopathy is most likely to develop when high doses of prednisolone have been continued for too long but may also occur in any patient on prolonged treatment with doses of prednisolone greater than ∼10 mg/day.31 If steroid myopathy is suspected, a gradual reduction in the dose of prednisolone, or
Inclusion body myositis
Although most patients with IBM continue to deteriorate in spite of corticosteroid and immunosuppressive treatment, in a small proportion of cases (∼10%) there is subjective and objective improvement in strength or stabilisation of the condition for a time.[32], [33], [34] As it is not clear which patients respond, our policy is to recommend a trial of prednisolone (∼0.5 mg/kg/day) and methotrexate (10 mg/week) in cases in which the condition is not too advanced and the risk of side-effects is
Acknowledgements
We thank Dr. Bev Phillips for her help in preparing the treatment algorithm and Mrs. S. Moncrieff for secretarial assistance.
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Cited by (32)
Polymyositis and dermatomyositis – challenges in diagnosis and management
2019, Journal of Translational AutoimmunityCitation Excerpt :However, there is still a high percentage of patients with IIM who fail to respond completely to glucocorticoids alone [225]. Intravenous immune globulin therapy has been shown to be effective in severe and rapidly progressive or refractory PM and DM in several clinical trials [219,226,227]. Azathioprine (AZA), a derivative of 6-mercaptopurine, is administered orally at a dose of 2–3 mg/kg daily and is usually effective after 4–8 months, according to a small number of case series or case studies [228–231].
Sporadic inclusion body myositis
2012, Seminarios de la Fundacion Espanola de ReumatologiaIdiopathic inflammatory myopathies: Definition and management of refractory disease
2011, Autoimmunity ReviewsCitation Excerpt :The author's opinion is the introduction as soon as possible of methotrexate (7.5 mg/weekly to 30 mg/weekly oral or parental) or azathioprine (2.5 mg/kg/day) in this specific group of patients. This strategy enhances the possibility of “muscle sparing effect” and lower exposure to high doses of steroids, while it improves disease control [45]. However, there are some particular patients that justify a complementary approach:
Myopathies due to toxic agents and drugs (corticosteroids and lipid-lowering drugs excepted)
2008, Revue du Rhumatisme (Edition Francaise)Dermatomyositis, lobar panniculitis and inflammatory myopathy with abundant macrophages
2006, Neuromuscular Disorders