[Clinical, electrophysiological and immunological evaluation of the response to treatment with intravenous immunoglobulins in several immune-mediated neuropathies]. / Valoración clínica, electrofisiológica e inmunológica de la respuesta al tratamiento con inmunoglobulinas intravenosas en distinta neuropatías inmunomediadas.

ABSTRACT

INTRODUCTION AND AIMS: Chronic immune-mediated neuropathies are characterised by their being predominantly demyelinating, by being associated to specific antibodies and by their response to immunotherapy. We evaluated the clinical, electrophysiological and immunological responses following treatment with intravenous immunoglobulins (IVIg) in different clinical forms. CASE REPORTS We report on three patients with 1. Multifocal motor neuropathy, 2. Multifocal sensory-motor neuropathy, and 3. Hypertrophic brachial plexopathy, who were evaluated before and 14 days after treatment with IVIg by means of clinical scales (MRC, Rankin), electrophysiological studies (ENG-EMG), and antibody (antiganglioside) determination. The three patients showed clinical improvement (> 20% MRC, > 1 Rankin) between the 4th and 7th day after the infusion, and this was maintained for 4-16 weeks. The ENG in cases 1 and 2 revealed conduction block (CB) in some nerves, lowered amplitude in others, and signs of demyelination. Following treatment, the CB disappeared in some nerves, while in others there was an improvement in the distal amplitude (distal block), but with no correlative improvement in the proximal amplitude, revealing new CBs that had previously gone undetected. The sum of post-treatment amplitudes improved in cases 1 and 2. In case 3, we were unable to demonstrate the existence of CBs, although we believe that they did exist proximally, and we found indirect signs of CB in EMG. The three cases had increased antiganglioside IgM antibodies levels, which did not undergo any significant variations. CONCLUSIONS: A 'consistent' clinical improvement was observed following treatment with IVIg. There was no correlation between the electrophysiological response (although apparent) and the degree of clinical response. CBs exist at different levels in the same nerve, which can be revealed after treatment. Following therapy, antiganglioside antibody levels remain high.