International GBS Outcome Study (IGOS) is a study conducted by the members of the Inflammatory Neuropathy Consortium (INC) and Peripheral Nerve Society (PNS) on disease course and outcome in Guillain-Barré syndrome (GBS).

The IGOS aims to identify clinical and biological determinants and predictors of disease course and outcome in individual patients with Guillain-Barré syndrome, as early as possible after onset of disease.

GBS is a post-infectious immune-mediated polyradiculoneuropathy with a highly diverse clinical course and outcome despite partially effective forms of treatment(immunoglobulins and plasma exchange). Outcome in patients with GBS has not improved in the last two decades. At present about 10 to 20% of patients remain severely disabled and about 5% die. One explanation for this stagnation is the highly variable clinical course of GBS and the lack of knowledge about the factors that determine the clinical course in individual patients with GBS. GBS may consist of distinct pathogenic subgroups, in which disease onset and progression is influenced by different types of preceding infections, anti-neural antibodies and genetic polymorphisms. Optimal treatment of individual patients may depend on the pathogenesis and clinical severity. Patients with severe forms of GBS may possibly need more intensive treatment to recover. Patients with a milder course that fully recover after standard therapy could suffer from possibly more side effects of more aggressive forms of treatment. This could only be possible if there are prognostic models that accurately predict the clinical course in individual patients. Ideally such models should be based on clinical and biological predictors that are strongly associated with disease course and known as early as possible in the acute phase of illness, when treatment with immunomodulatory therapy is most effective. Prognostic models could help to guide selective trials in specific GBS subtypes. Because of this it will be possible to treat GBS with more effective and more individual therapy.

This study aims to identify clinical and biological determinants and predictors of disease course and outcome in individual patients with Guillain-Barré syndrome, as early as possible after onset of disease. This information will be used to understand the diversity in clinical presentation and response to treatment of GBS. This information will also be used to develop new prognostic models to predict the clinical course and outcome accurately in individual patients with GBS.

To address these research questions it is required to conduct a prospective study with standardized collection of clinical data and biomaterials from a large group of well-defined GBS patients during a long follow-up period. Such an extensive study in a relatively rare disease as GBS can be addressed only by intensive international collaboration.

Inclusion Criteria:

• Fulfil diagnostic criteria for GBS of National Institute of Neurological Disorders and Stroke (NINDS). Patients with Miller Fisher syndrome and all other variants of GBS, including overlap syndromes, can be included.
• Inclusion of all males and females of all ages, independent of disease severity and treatment
• Inclusion within two weeks of onset of weakness
• Inclusion of patients transferred from another hospital if the stay in the first hospital was less than one week
• Opportunity to conduct a follow-up of at least one year
• Informed consent of patient or, in case of children, of parents or legal guardians

Exclusion Criteria:

• There are no exclusion criteria

All patients with Guillain-Barré syndrome (GBS) or variants of GBS, including the Miller Fisher syndrome (MFS) and overlap syndromes.