Background: The clinical and pathologic spectrum of Guillain Barre Syndrome (GBS) has expanded to include both demyelinating and axon loss forms. GBS may also have atypical presentations. For these reasons, clinicians are more likely to overlook unrelated disorders that mimic GBS.

Review Summary: In this article, the classic presentation and variants of GBS are briefly reviewed. Disorders that mimic GBS are reviewed in detail, including those caused by neurotoxins, heavy metals, chemical toxins, drugs, vasculitis, hereditary disorders, infections, critical illness, and myelopathy. Illustrative case studies accompany a number of the descriptions.

Conclusions: Failure to recognize the mimics of GBS can lead to erroneous diagnosis, inappropriate results, and significant morbidity. Appropriate diagnosis requires a combination of careful history and examination, and accurate interpretation of diagnostic testing.