Diagnosis of Demyelinating Neuropathies

Clinical Assessment

The diagnosis of demyelinating neuropathies requires a systematic integration of clinical features, electrophysiological studies showing demyelination, and cerebrospinal fluid analysis demonstrating cytoalbuminologic dissociation, with the critical distinction being the time course: progression over days to 4 weeks suggests Guillain-Barré syndrome (GBS), while progression beyond 2 months indicates Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) 1, 2
Progressive bilateral weakness of arms and legs is a required diagnostic feature for GBS, with legs may be initially involved alone 1, 3
Absent or decreased tendon reflexes in affected limbs at some point during the clinical course is a required diagnostic feature for GBS 1, 3
The American Academy of Neurology recommends considering GBS in patients with progressive bilateral weakness with areflexia, and assessing for red flags that suggest alternative diagnoses 1, 3
The European Academy of Neurology suggests that progression over more than 2 months is a key distinguishing feature of CIDP, versus days to weeks in GBS 2

Cerebrospinal fluid analysis should be performed to look for cytoalbuminologic dissociation, which is elevated protein with normal cell count, a critical finding in GBS and CIDP 2
Electrophysiological studies, including nerve conduction studies, should be performed to document demyelinating features and classify electrophysiological subtype 1, 3
The American Academy of Neurology recommends considering nerve biopsy only for atypical presentations of CIDP 2

The diagnostic algorithm for demyelinating neuropathies involves establishing the time course of progression, confirming clinical features, obtaining CSF analysis, performing nerve conduction studies, and completing additional workup for CIDP, including serum electrophoresis with immunofixation, metastatic bone survey, HIV testing, and considering MRI of plexus 1, 2, 3
The European Academy of Neurology suggests that Step 1 in the diagnostic algorithm is to establish the time course of progression, with days to 4 weeks suggesting GBS, and beyond 2 months suggesting CIDP 1, 2
The American Academy of Neurology recommends that Step 2 in the diagnostic algorithm is to confirm clinical features, including progressive bilateral weakness with areflexia, and assessing for red flags that suggest alternative diagnoses 1, 3