LONG-TERM FOLLOW-UP OF MULTIFOCAL MOTOR NEUROPATHY WITH CONDUCTION BLOCK UNDER TREATMENT

Eighteen patients (15 men, three women; age range 30 to 71 years, mean 45.8 years) with multifocal motor neuropathy treated with high dose i ntravenous immunoglobulin (IVIg) were evaluated for nine to 48 months (mean follow up 25.3 months). The median time between onset of multifo cal motor neuropathy and treatment was 5.8 years. The dose of IVIg was 0.4 g/day for three to five days. The interval between each treatment was determined for each patient by the evaluation of the effect of th e first course. Muscle strength was evaluated by a computerised analys er. Clinical improvement was seen in 12 patients treated with IVIg (67 %). Isometric strength increased from 32% to 97% (mean 54.5%) of the i nitial value. Functional scales corroborated these findings. No clear predictive factors of response to IVIg was found except the presence o f high titres of IgM anti-GM1 antibodies. Often, patients needed repea ted courses of IVIg to maintain the improvement. In two patients, IVIg infusions were stopped without signs of relapse after one year. Four patients were initially treated with prednisone (1 mg/kg/day), without any clear improvement. Five patients with no response to IVIg or who were IVIg dependent were treated with cyclophosphamide, but only one s howed improvement. These results show the long term benefits and safet y of IVIg in multifocal motor neuropathy but also the transient effect of this expensive treatment in most patients.