Peripheral nerve demyelination in multiple sclerosis.
OBJECTIVE
To elucidate the frequency of peripheral nerve demyelination in multiple sclerosis (MS). There are a number of case reports describing MS patients associated with demyelinating neuropathy, but its frequency in a whole MS population is unknown.


METHODS
Extensive nerve conduction studies were prospectively performed in 60 consecutive patients with relapsing-remitting MS. Multiple excitability measurements using threshold tracking were also performed in median motor axons and superficial radial sensory axons.


RESULTS
Nerve conduction abnormalities suggestive of demyelination were found for 3 (5%) of the patients. Two of them developed clinically evident neuropathy, whereas the remaining one had only generalized areflexia in addition to MS symptoms/signs. In all the three, MS preceded demyelinating neuropathy by several years. Excitability testing showed that supernormality and threshold electrotonus at the tested sites (median motor axons at the wrist, and radial sensory axons at the mid-forearm) were similar in the normal and MS groups.


CONCLUSIONS
MS patients do not generally have peripheral nerve demyelination, but approximately 5% of patients develop demyelinating neuropathy. The association could result from a common pathogenesis possibly due to epitope spreading during the long course of MS.


CONCLUSIONS
Association of chronic inflammatory demyelinating polyneuropathy with MS is not frequent, but needs to be recognized as a treatable condition.
Misawa
Sonoko
S
Department of Neurology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8670, Japan.
Kuwabara
Satoshi
S
Department of Neurology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8670, Japan. Electronic address: kuwabara-s@faculty.chiba-u.jp.
Mori
Masahiro
M
Department of Neurology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8670, Japan.
Hayakawa
Sei
S
Department of Neurology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8670, Japan.
Sawai
Setsu
S
Department of Neurology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8670, Japan.
Hattori
Takamichi
T
Department of Neurology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8670, Japan.
D000200:Action Potentials / Q000502:physiology / Q000528:radiation effects; D000328:Adult; D000368:Aged; D003711:Demyelinating Diseases / Q000209:etiology* / Q000473:pathology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D009103:Multiple Sclerosis / Q000150:complications* / Q000473:pathology*; D009431:Neural Conduction / Q000502:physiology / Q000528:radiation effects; D010525:Peripheral Nerves / Q000503:physiopathology*; D011446:Prospective Studies; D012189:Retrospective Studies