A prospective open label trial of add on therapy with intravenous immunoglobulin (IVIg) was carried out in 16 patients with inflammatory myopathy who had continued to deteriorate or had relapsed on conventional therapy. The response was assessed using isometric myometry, functional scales, MRC grading, and serum creatine kinase concentrations with a three month run in period before commencement of IVIg. Five of seven patients with isolated dermatomyositis or polymyositis and all four patients with an overlap syndrome responded to IVIg with partial or complete remission of disease and normalisation of serum creatine kinase concentrations. None of five patients with inclusion body myositis showed any functional improvement although myometry scores improved in some muscles in one case. It is concluded that IVIg is an effective therapeutic option in patients with drug resistant polymyositis or dermatomyositis. However, further controlled trials are required to confirm the efficacy of this form of treatment and to establish optimal doses and administration regimes.
Inflammatory myopathy is a group of disorders with progressive muscle weakness being the major symptom. Quantitative assessment of muscle function is important when evaluating the response of these conditions to treatment and various methods, including manual muscle testing, myometry and isokinetic dynamometry, have been used for the assessment of muscle strength. The aims of this study were to compare, in patients with inflammatory myopathy, the maximum isometric quadriceps and hamstrings torques using a hand-held myometer and a dynamometer (Kin-Com), and to compare make and break tests using myometry. The results showed that in stronger quadriceps the myometer tests underestimated maximum torque as measured with the dynamometer, and that in weaker quadriceps there was no difference in torque with the different methods. There was no difference in hamstrings make torques for the two instruments. The break myometer torques were greater than the make torques for both muscle groups. These findings indicate that when using myometry, break tests measure maximum torque more accurately than make tests, and that isometric dynamometry is preferable to myometry when testing maximum strength of large muscles of near normal strength.
The treatment of the immune-mediated inflammatory myopathies remains largely empirical. Corticosteroids are usually effective in polymyositis and dermatomyositis but may need to be combined with methotrexate or azathioprine in some patients. Intravenous immunoglobulin (IVIg) is effective as add-on therapy in some patients not adequately controlled with steroids or immunosuppressive agents, but further controlled trials of IVIg are necessary to define the indications and optimal dose regimens. Cyclophosphamide, cyclosporin, or chlorambucil may be effective in patients with refractory polymyositis or dermatomyositis. Low-dose whole body or lymphoid irradiation is a last option in severely disabled patients resistant to all other treatments. As a small proportion of patients with inclusion body myositis respond to corticosteroid or immunosuppressive therapy, a 3-6-month trial of such therapy is justified in this condition. More specific immunotherapy for these disorders awaits identification of the target antigens and further clarification of the immunopathogenetic mechanisms.
'/%3e%3c/defs%3e%3cpath fill='%23012169' d='M0 0h10080v5040H0z'/%3e%3cpath stroke='%23fff' stroke-width='.6' d='m0 0 6 3m0-3L0 3' clip-path='url(%23b)' transform='scale(840)'/%3e%3cpath stroke='%23e4002b' stroke-width='.4' d='m0 0 6 3m0-3L0 3' clip-path='url(%23c)' transform='scale(840)'/%3e%3cpath stroke='%23fff' stroke-width='840' d='M2520 0v2520M0 1260h5040'/%3e%3cpath stroke='%23e4002b' stroke-width='504' d='M2520 0v2520M0 1260h5040'/%3e%3cg fill='%23fff'%3e%3cuse xlink:href='%23d' x='2520' y='3780'/%3e%3cuse xlink:href='%23a' x='7560' y='4200'/%3e%3cuse xlink:href='%23a' x='6300' y='2205'/%3e%3cuse xlink:href='%23a' x='7560' y='840'/%3e%3cuse xlink:href='%23a' x='8680' y='1869'/%3e%3cuse xlink:href='%23e' x='8064' y='2730'/%3e%3c/g%3e%3c/svg%3e)