What causes Guillain-Barré Syndrome (GBS)?

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From the Guidelines

Guillain-Barré syndrome (GBS) is primarily caused by an abnormal immune response that attacks the peripheral nerves, triggered by preceding infections such as Campylobacter jejuni, cytomegalovirus, Epstein-Barr virus, influenza, Zika virus, and COVID-19 1. The most common trigger is a preceding infection, typically occurring 1-3 weeks before GBS symptoms develop.

  • Campylobacter jejuni, a bacterial infection causing gastroenteritis, is the most frequently identified pathogen, accounting for about 30% of cases.
  • Other infectious triggers include cytomegalovirus, Epstein-Barr virus, influenza, Zika virus, and COVID-19.
  • In rare cases, GBS can develop following vaccination, surgery, or trauma. The condition involves the immune system mistakenly attacking the myelin sheath or axons of peripheral nerves, leading to weakness, numbness, and paralysis that typically begins in the legs and can ascend to affect the arms and respiratory muscles. The exact mechanism involves molecular mimicry, where antibodies produced against infectious agents cross-react with components of peripheral nerve tissue due to structural similarities, as noted in a recent study 1. This autoimmune attack disrupts nerve signal transmission, resulting in the characteristic symptoms of GBS. Key points to consider in the diagnosis and management of GBS include early recognition, admission to the intensive care unit, treatment indication and selection, monitoring and treatment of disease progression, prediction of clinical course and outcome, and management of complications and sequelae, as outlined in a guideline for the diagnosis and management of GBS 1.

From the Research

Causes of Guillain-Barré Syndrome

The causes of Guillain-Barré syndrome (GBS) are complex and multifaceted. Some of the key factors that contribute to the development of GBS include:

  • Preceding bacterial or viral infections, with Campylobacter jejuni being the most frequent antecedent pathogen 2, 3, 4, 5, 6
  • Immune responses directed towards the infecting organisms, which can cross-react with neural tissues due to molecular mimicry 2, 3, 5, 6
  • Autoantibody-mediated immune processes, which can trigger demyelination or axonal damage in peripheral nerves 3, 4, 5

Infectious Triggers

Some of the most common infectious triggers of GBS include:

  • Campylobacter jejuni, which is responsible for about a third of GBS cases 5
  • Mycoplasma pneumoniae 5
  • Cytomegalovirus 4, 5
  • Zika virus 3
  • Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 3

Non-Infectious Triggers

While less common, non-infectious triggers can also contribute to the development of GBS, including:

  • Underlying systemic diseases 6
  • Immunocompromised states 6
  • Vaccines, although the exact mechanism is not yet fully understood 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Guillain-Barré syndrome.

Lancet (London, England), 1998

Research

Guillain-Barré syndrome.

Lancet (London, England), 2021

Research

Guillain Barré syndrome.

Molecular pathology : MP, 2001

Research

Triggers of Guillain-Barré Syndrome: Campylobacter jejuni Predominates.

International journal of molecular sciences, 2022

Research

Infectious and noninfectious triggers in Guillain-Barré syndrome.

Expert review of clinical immunology, 2013

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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