Can electrophysiology differentiate polyneuropathy with anti-MAG/SGPG antibodies from chronic inflammatory demyelinating polyneuropathy?

Abstract

OBJECTIVES:

Patients with polyneuropathy and antibodies to myelin-associated glycoprotein (MAG) and sulphated glucuronyl paragloboside (SGPG) differ from chronic inflammatory demyelinating polyneuropathy (CIDP) because of a slower, progressive course, symmetrical and predominantly sensory involvement of legs, predominantly distal slowing of motor conductions, and poorer response to therapy. We studied whether a wide set of electrophysiologic parameters may differentiate these two neuropathies.

METHODS:

We reviewed the electrophysiological studies of 10 patients with anti-MAG/SGPG antibodies and 22 with CIDP examining: (1) motor conduction velocity and distal compound muscle action potential amplitude; (2) conduction block (CB) and temporal dispersion; (3) distal motor latency and terminal latency index (TLI); (4) F wave and proximal conduction time; and (5) sensory conduction and occurrence of abnormal median with normal sural sensory potential.

RESULTS:

Anti-MAG/SGPG neuropathies showed: (1) more severe involvement of peroneal nerves; (2) more frequent disproportionate distal slowing of motor conductions (TLI< or =0.25) and absent sural potential, and (3) no CB. However 3/22 CIDP patients also had at least two nerves with TLI< or =0.25 and no CB.

CONCLUSIONS:

Electrophysiologic findings suggest in anti-MAG/SGPG neuropathy a length-dependent process with a likely centripetal evolution. A disproportionate slowing of conduction in distal segments of motor nerves suggests the diagnosis of anti-MAG/SGPG neuropathy, although it is not pathognomonic.

• Authors: Margherita Capasso, Filomena Torrieri, Antonio Di Muzio, Maria Vittoria De Angelis, Alessandra Lugaresi, Antonino Uncini
• Journal: Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology (Clin Neurophysiol) Vol. 113 Issue 3 Pg. 346-53 (Mar 2002) ISSN: 1388-2457 [Print] Netherlands
• PMID: 11897535 (Publication Type: Journal Article)

Chemical References

• Autoantibodies
• Globosides
• Myelin-Associated Glycoprotein
• sulfate-3-glucuronyl paragloboside

Topics

• Adult
• Aged
• Aged, 80 and over
• Autoantibodies (blood)
• Diagnosis, Differential
• Electric Stimulation
• Electrodiagnosis (methods)
• Electrophysiology (methods)
• Female
• Globosides (immunology)
• Humans
• Male
• Middle Aged
• Myelin-Associated Glycoprotein (immunology)
• Neural Conduction
• Peroneal Nerve (physiopathology)
• Polyneuropathies (blood, diagnosis, immunology)
• Polyradiculoneuropathy, Chronic Inflammatory Demyelinating (diagnosis)
• Predictive Value of Tests
• Reaction Time
• Retrospective Studies
• Sural Nerve (physiopathology)