Lumbar puncture for cerebrospinal fluid (CSF) studies is recommended in patients with suspected GBS. Characteristic findings during the acute phase include albuminocytologic dissociation, which is an elevation in CSF protein (> 0.55 g/L) without a corresponding elevation in white blood cells. This is thought to reflect the widespread nerve root inflammation.
Basic laboratory studies, such as complete blood counts and metabolic panels, are typically normal and of limited value in the workup. However, they are often obtained to exclude other diagnoses and better assess functional status and prognosis.
Electromyography (EMG) and nerve conduction studies (NCSs) may be helpful in the diagnosis. Needle EMG may be normal in acute nerve lesions, and it may take 3-4 weeks for fibrillation to develop. Abnormalities in NCSs that are consistent with demyelination are sensitive and represent specific findings for classic GBS. However, electrodiagnostic studies can be completely normal in acute GBS and a normal study does not rule GBS.
Imaging studies, such as MRIs and CT of the spine, may be more helpful in excluding other diagnoses, such as mechanical causes of myelopathy, than in assisting in the diagnosis of GBS.
Learn more about the workup for GBS.
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Cite this: Helmi L. Lutsep. Fast Five Quiz: Guillain-Barré Syndrome Practice Essentials - Medscape - Dec 06, 2022.