What are the investigations for Guillain-Barré Syndrome (GBS)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Article Review Status
Submitted
Under Review
Approved

Last updated: March 30, 2025 • View editorial policy

From the Guidelines

Investigations for Guillain-Barré syndrome (GBS) should include cerebrospinal fluid (CSF) analysis, nerve conduction studies, and relevant blood tests, as these are crucial for confirming the diagnosis, determining the subtype of GBS, and guiding treatment decisions. The diagnosis of GBS can be challenging due to its heterogeneous clinical presentation and the lack of highly sensitive and specific diagnostic tools or biomarkers 1.

Key Investigations

  • CSF analysis typically shows albuminocytologic dissociation (elevated protein with normal cell count), which is a hallmark finding of GBS 2.
  • Nerve conduction studies demonstrate slowed conduction velocities, conduction blocks, or temporal dispersion consistent with demyelination, although these may be normal early in the disease course or in patients with mild disease 2.
  • Blood tests should include complete blood count, electrolytes, liver and renal function tests, and specific antibody tests like anti-ganglioside antibodies (particularly anti-GM1, anti-GD1a, and anti-GQ1b) 3.
  • Microbiological investigations may be warranted to identify preceding infections, such as Campylobacter jejuni, cytomegalovirus, Epstein-Barr virus, or Zika virus 1.
  • Pulmonary function tests, including monitoring of vital capacity and negative inspiratory force, are essential to predict the need for ventilatory support, as respiratory failure is a significant complication of GBS 3.

Importance of Early Diagnosis and Treatment

Early diagnosis is crucial as prompt treatment with intravenous immunoglobulin (IVIG) at 0.4g/kg/day for 5 days or plasma exchange (5 exchanges over 2 weeks) significantly improves outcomes in patients with GBS 1. The efficacy of these treatments underscores the importance of timely and accurate diagnosis, which can be facilitated by the investigations outlined above.

Clinical Considerations

It is also important to consider the clinical context and potential for atypical presentations or clinical variants of GBS, which may require additional or specialized investigations 1. Regular monitoring and a multidisciplinary approach to care can help manage the complexities of GBS and improve patient outcomes.

From the Research

Investigations of Guillain-Barré Syndrome

  • Guillain-Barré syndrome (GBS) is an acute polyneuropathy with a variable degree of weakness that reaches its maximal severity within 4 weeks, often preceded by an infection and generally running a monophasic course 4.
  • The disease can be subdivided into acute inflammatory demyelinating polyneuropathy (AIDP), acute motor axonal neuropathy (AMAN), and Miller-Fisher syndrome (MFS), with overlap syndromes existing 4.
  • Both intravenous immunoglobulin (IVIg) and plasma exchange (PE) are effective in treating GBS, while steroids alone are ineffective 4.
  • About 10% of GBS patients experience a secondary deterioration within the first 8 weeks after starting IVIg, requiring repeated IVIg treatment 4.
  • Advances in prognostic modeling have led to the development of a simple prognostic scale that predicts the chance of artificial ventilation and an outcome scale to determine the chance of walking unaided after 1, 3, or 6 months 4.

Diagnosis and Management

  • Diagnosis and management of GBS can be complicated due to its heterogeneous clinical presentation and disease course, with no international clinical guidelines currently available 5.
  • A globally applicable guideline for the diagnosis and management of GBS has been developed, based on current literature and expert consensus, with a ten-step structure to facilitate its use in clinical practice 5.
  • The guideline covers early recognition and diagnosis of GBS, 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 5.

Predictors of Outcomes

  • Prompt identification of patients at high risk of poor outcomes is crucial for timely intervention, with predictors of poor outcomes including older age, a more abrupt onset pattern, low compound muscle action potential (CMAP), and slow nerve conduction 6.
  • Combining clinical data with nerve conduction study and electromyography data can assist in predicting outcomes of both GBS patients and the AIDP subgroup 6.
  • Abnormal tibial F responses can predict poor outcomes, and early identification of high-risk patients facilitates tailored interventions 6.

Electrophysiologic Studies

  • Electrophysiologic studies, such as nerve conduction studies (NCS) and antiperipheral nerve myelin antibody (A-PNM Ab) titers, can be used to monitor the effects of plasma exchange and antibody rebound in GBS patients 7.
  • In some patients plasmapheresed, A-PNM Ab may rebound, associated with further conduction dysfunction, and these patients may benefit from further plasmapheresis 7.

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.