Oligoclonal immunoglobulin G in cerebrospinal fluid of myasthenia gravis patients

Myasthenia Gravis-An Analysis of Multimodal Evoked Potentials

INTRODUCTION

The aim of this study is a comprehensive analysis of the parameters of exogenous evoked potentials (visual, brainstem auditory, and somatosensory) in patients with myasthenia gravis (MG), a prototype of both neuromuscular junction disease and autoimmune disease. The study also seeks to isolate electrophysiological changes that may indicate disorders within the central and/or peripheral nervous system.

METHODS

A total of forty-two consecutive patients with myasthenia gravis (24 women, 18 men) were included in the study. All of the patients underwent EP examination. MR images were also analyzed.

RESULTS

In the group of MG patients, the latency of P100 (113.9 ± 13.9; p < 0.0001) VEP, wave III (3.92 ± 0.29; p = 0.015), wave V (5.93 ± 0.32; <0.0001), interlatency III-V (2.00 ± 0.12; p < 0.0001), interlatency I-V (4.20 ± 0.28; p < 0.001) BAEP, and all components of SEP (N9, P10, N13, P16, N20, P22) were significantly longer. Mean wave I and V amplitude BAEP were relatively lower.

CONCLUSIONS

The results of the study suggest the presence of disturbances in the bioelectric activities of the central and peripheral nervous system in MG patients.

Myasthenia Gravis With Reversible Pyramidal Tract Damage and Pseudo Internuclear Ophthalmoplegia. A Case Report and Literature Review

Myasthenia gravis (MG) is a rare and treatable antibody-mediated autoimmune disease. Pseudo internuclear ophthalmoplegia (-INO) or pyramidal tract damage is rarely observed in MG, and there were no known cases of MG with both pseudo-INO and pyramidal tract damage. Here, we report a case of a 61-year-old female suffering from MG accompanied by pseudo-INO and pyramidal tract damage with a rapid progressive course. Her blood and cerebrospinal fluid (CSF) tests were normal, except for the presence of the anti-acetylcholine receptor antibody. CT and contrast enhancement of the chest showed a thymic involution. MRI and contrast enhancement images of the brain and whole spine were normal. Both the clinical response to the administration of neostigmine and the repetitive nerve stimulation test were positive. The motor evoked potentials at lower limb recordings were normal. According to her signs, symptoms, decrementing response on repetitive stimulation test, elevated anti-acetylcholine receptor antibody and positive response to neostigmine, the patient was diagnosed as having MG. After treatment with pyridostigmine, intravenous immunoglobulin, prednisone acetate tablets and methotrexate, all her symptoms disappeared, including pseudo-INO and pyramidal tract damage. To our best knowledge, this is the first report of a case of MG with both pseudo-INO and pyramidal tract damage. Based on our case and a review of the literature, we propose that pyramidal tract damage and pseudo-INO can be two signs of MG, and that MG can cause damage to other systems besides neuromuscular junctions.

Absence of Oligoclonal IgG Bands and Anti-Achr Antibodies in the Cerebrospinal Fluid of Patients with Myasthenia Gravis

Myasthenia gravis (MG) is a neuromuscular disorder in which antibodies are directed against the nicotinic acetylcholine receptor (AChR) at the neuromuscular junction. Some investigators describe the existence of oligoclonal IgG bands and anti-AChR antibodies in the cerebrospinal fluid (CSF) of MG patients while other refuse it. This study was performed in 15 patients with clinical and electrophysiological diagnosis of MG. Oligoclonal IgG bands (OCB) and antibodies to the AChR from human skeletal muscle were determined in the serum and the CSF of the above MG patients. The last one was done in order to investigate any possible central nervous system (CNS) involvement.

It was found that all the MG patients who had a high titre of anti- AChR antibodies in the serum (mean titre 29.2±24.3 nM, range 1.8 to 62 nM) did not present OCB and anti-AChR antibodies in their CSF. On the same time, in a group of 10 patients with a definite multiple sclerosis it was found that eight of them presented OCB in their CSF while the results were negative in another group of 10 patients without evidence of CNS disease. The last two groups served as control groups.

Our findings are in accordance with the concept that MG is a pure neuromuscular disorder.