Electrophysiological classification of Guillain-Barré syndrome: clinical associations and outcome. Plasma Exchange/Sandoglobulin Guillain-Barré Syndrome Trial Group

Inexcitability of nerves in a fulminant case of Guillain-Barré syndrome

A 45-year-old woman presented with a recent sensorimotor deficiency in all 4 limbs, and the next day she was totally paralyzed. A slight motor improvement began on day 27. The cerebrospinal fluid had normal cellularity, but the protein varied from 90 mg/dL on the first day to 800 mg/dL on day 15, and then 290 mg/dL on day 33. Electrophysiologic studies performed on days 15 and 23 revealed a universal peripheral nerve inexcitability. A superficial peroneal nerve biopsy was performed on day 23. Nine fascicles were examined on semi-thin sections and myelinated fiber damage varied greatly from one fascicle to another. At ultrastructural examination, certain axons were severely damaged, but the others were quite well preserved and were naked or wrapped in a myelin sheath presenting a multivesicular degeneration. A few fibers had a better-preserved myelin sheath that was sometimes dissociated by elongated processes from an invading histiocyte. Six cases of fulminant Guillain-Barré syndrome with inexcitability of nerves and ultrastructural examination of nerve fragments have been reported. Electrophysiologic study is often ambiguous and cannot determine the precise origin of such an axonal degeneration. Therefore, ultrastructural analysis of a nerve biopsy is mandatory in this setting.

Anti-PMP22 antibodies in patients with inflammatory neuropathy

An experimental model of inflammatory radiculoneuropathy is induced by immunising rats with peripheral myelin protein 22 (PMP22). We have investigated whether PMP22 may be important in inducing human inflammatory neuropathy. We examined sera of patients with Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), other neuropathies (ONP) and normal controls for IgM and IgG antibodies against PMP22 by ELISA (against synthetic PMP22 extracellular peptide fragments) and Western blot (against cauda equina). Antibodies were detected by both methods in 52% of patients with GBS, 35% with CIDP, 3% with ONP and no normal controls. We conclude that an immune response against PMP22 may play a role in the pathogenesis of the inflammatory neuropathies.

Guillain-Barré syndrome occurring in two women after ketoacidosic comatose state disclosing an insulin-dependent diabetes mellitus

We report two women who presented with a Guillain-Barré syndrome just after a ketoacidosic comatose state disclosing an insulin-dependent diabetes mellitus. One had characteristic clinical signs and the other had major motor involvement. At neurophysiologic investigations, one had typical demyelinating neuropathy whereas the second had mainly axonal degeneration. At ultrastructural examination of a peripheral nerve biopsy, features of macrophage-associated demyelination were present in both nerve specimens, thus confirming the diagnosis of acute inflammatory demyelinating polyneuropathy, i.e., Guillain-Barré syndrome. Prominent axonal involvement was also present in the motor nerves of the second patient. Insulin therapy had to be permanently continued and these two cases are quite different from the transient diabetes sometimes observed in certain cases of Guillain-Barré syndrome. Both the latter and insulin-dependent diabetes mellitus probably have auto-immune mechanisms. It is likely that in our two patients both auto-immune diseases were triggered by a common event. Such cases of Guillain-Barré syndrome have to be distinguished from other acute diabetic neuropathies.

Pathogenesis of Guillain-Barré syndrome

Recent neurophysiological and pathological studies have led to a reclassification of the diseases that underlie Guillain-Barré syndrome (GBS) into acute inflammatory demyelinating polyradiculoneuropathy (AIDP), acute motor and sensory axonal neuropathy (AMSAN) and acute motor axonal neuropathy (AMAN). The Fisher syndrome of ophthalmoplegia, ataxia and areflexia is the most striking of several related conditions. Significant antecedent events include Campylobacter jejuni (4-66%), cytomegalovirus (5-15%), Epstein-Barr virus (2-10%), and Mycoplasma pneumoniae (1-5%) infections. These infections are not uniquely associated with any clinical subtype but severe axonal degeneration is more common following C. jejuni and severe sensory impairment following cytomegalovirus. Strong evidence supports an important role for antibodies to gangliosides in pathogenesis. In particular antibodies to ganglioside GM1 are present in 14-50% of patients with GBS, and are more common in cases with severe axonal degeneration associated with any subtype. Antibodies to ganglioside GQ1b are very closely associated with Fisher syndrome, its formes frustes and related syndromes. Ganglioside-like epitopes exist in the bacterial wall of C. jejuni. Infection by this and other organisms triggers an antibody response in patients with GBS but not in those with uncomplicated enteritis. The development of GBS is likely to be a consequence of special properties of the infecting organism, since some strains such as Penner 0:19 and 0:41 are particularly associated with GBS but not with enteritis. It is also likely to be a consequence of the immunogenetic background of the patient since few patients develop GBS after infection even with one of these strains. Attempts to match the subtypes of GBS to the fine specificity of anti-ganglioside antibodies and to functional effects in experimental models continue but have not yet fully explained the pathogenesis. T cells are also involved in the pathogenesis of most or perhaps all forms of GBS. T cell responses to any of three myelin proteins, P2, PO and PMP22, are sufficient to induce experimental autoimmune neuritis. Activated T cells are present in the circulation in the acute stage, up-regulate matrix metalloproteinases, cross the blood-nerve barrier and encounter their cognate antigens. Identification of the specificity of these T cell responses is still at a preliminary stage. The invasion of intact myelin sheaths by activated macrophages is difficult to explain according to a purely T cell mediated mechanism. The different patterns of GBS are probably due to the diverse interplay between antibodies and T cells of differing specificities.

Intravenous immunoglobulin in the treatment of autoimmune neuromuscular diseases: present status and practical therapeutic guidelines

This review summarizes the current status of intravenous immunoglobulin (IVIg) in the treatment of autoimmune neuromuscular disorders and the possible mechanisms of action of the drug based on work in vivo, in vitro, and in animal models. Supply of idiotypic antibodies, suppression of antibody production, or acceleration of catabolism of immunoglobulin G (IgG) are relevant in explaining the efficacy of IVIg in myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS), and antibody-mediated neuropathies. Suppression of pathogenic cytokines has putative relevance in inflammatory myopathies and demyelinating neuropathies. Inhibition of complement binding and prevention of membranolytic attack complex (MAC) formation are relevant in dermatomyositis (DM), Guillain-Barré syndrome (GBS), and MG. Modulation of Fc receptors or T-cell function is relevant in chronic inflammatory demyelinating polyneuropathy (CIDP), GBS, and inflammatory myopathies. The clinical efficacy of IVIg, based on controlled clinical trials conducted in patients with GBS, CIDP, multifocal motor neuropathy (MMN), DM, MG, LEMS, paraproteinemic IgM anti-myelin-associated glycoprotein (anti-MAG) demyelinating polyneuropathies, and inclusion body myositis is summarized and practical issues related to each disorder are addressed. The present role of IVIg therapy in other disorders based on small controlled or uncontrolled trials is also summarized. Finally, safety issues, risk factors, adverse reactions, spurious results or serological tests, and practical guidelines associated with the administration of IVIg in the treatment of neuromuscular disorders are presented.

Clinical presentation and outcome of Guillain-Barré and related syndromes in relation to anti-ganglioside antibodies

We correlated the clinical features of 78 patients with Guillain-Barré syndrome (GBS) or related variants, with the presence of serum antibodies to the gangliosides GM1, GM2, GD1a, GD1b and GQ1b in order to determine whether these antibodies may influence the clinical presentation or outcome of GBS. Sixty-three patients had typical GBS (81%), nine a pure motor form (11%), three a paraparetic form (4%), and three had Miller Fisher syndrome (MFS). IgG or IgM (or both) anti-ganglioside antibodies were found by ELISA in 37% of patients, including 36% with typical, 33% with pure motor and 100% with MFS. Beside the constant occurrence of anti-GQ1b antibodies in patients with MFS (P<0.00001), the other clinical forms were not associated with a specific anti-ganglioside reactivity. Anti-GM1 and anti-GD1a antibodies tended to be associated with a worse disability at 6 month than other or no reactivity and, similarly to anti-GM2 antibodies, with a more frequent respiratory impairment. Anti-GM2 and anti-GD1b antibodies were always associated with typical GBS and, in all but one patient, with a complete recovery; still they were found in only 13 and 3%, respectively, of the patients with this presentation. Anti-GQ1b antibodies, though always associated with ophthalmoplegia and ataxia in both MFS and GBS, were found in only 36 and 26%, respectively, of patients with these symptoms. Even if different anti-ganglioside antibodies tend to be associated with some clinical features possibly suggesting that they may influence the clinical presentation or outcome, with the exception of anti-GQ1b antibodies for ophthalmoplegia and ataxia, they do not permit to predict the clinical presentation or outcome in individual patients.

Guillain-Barré syndrome

The concepts of Guillain-Barré syndrome have changed substantially over the last 10 years, and the last 2 years have been no exception. Guillain-Barré syndrome is now recognized as a heterogeneous disorder with many clinical manifestations. Most current investigations are centered on the hypothesis of molecular mimicry. The major challenge now is to identify the precise mechanisms of nerve fiber injury and to determine how to prevent immune injury.

Tracheostomy in Guillain-Barré syndrome

Specific treatment has been shown to shorten the duration of mechanical ventilation in Guillain-Barré syndrome (GBS) and could obviate the need for tracheostomy in a significant proportion of patients. However, the factors predictive of prolonged ventilation are undetermined, and the timing and use of tracheostomy in patients with GBS have not been systematically studied. The medical records of 60 patients ventilated for GBS were reviewed. Only 13 patients (22%) could be weaned within 3 weeks. Patients ventilated longer were significantly older (P = 0.04), and 21% had underlying pulmonary disease. Median duration of ventilation in patients treated with plasma exchange (n = 31) was not shortened. Fifty-two patients (87%) received a tracheostomy at a median of 9 days after intubation. In this series, where patients with comorbidity were included, tracheostomy was still necessary in the majority of ventilated patients. This procedure can be anticipated in elderly patients and in the presence of preexisting pulmonary disease.

Antibodies to GD1alpha and to GQ1beta in Guillain-Barré syndrome and the related disorders

Certain species of anti-ganglioside antibodies are associated with specific clinical features in various neurologic diseases. Serum autoantibodies to these minor gangliosides were investigated in a number of neurological diseases in order to examine the biological functions of GD1alpha and GQ1beta. Eleven patients with Guillain-Barré syndrome had remarkably high IgG anti-GD1alpha antibody titers, but no GD1alpha was detected in human peripheral nerve. An absorption study showed that IgG anti-GD1alpha antibodies from eight of the 11 patients were significantly absorbed by GD1a and GM1b, indicative that the IgG anti-GD1alpha antibodies cross-react with GD1a and GM1b. Both GD1a and GM1b have been reported to be target molecules for serum antibodies in certain patients with Guillain-Barré syndrome. GD1alpha may induce the production of IgG anti-GD1alpha antibody which cross-reacts with GD1a or GM1b, and subsequently functions in the development of Guillain-Barré syndrome. The IgGs from six patients with Fisher's syndrome who had the anti-GQ1beta antibody had anti-GQ1b activity as well. All the patients had external ophthalmoplegia, but no GQ1beta was detected in the human oculomotor nerve, further evidence that GQ1b, not GQ1beta, is the molecule targeted by the autoantibody in Fisher's syndrome.