1: Wien Klin Wochenschr 1995;107(10):301-8
[Multifocal-motor neuropathy and motor neuropathy with multifocal
conduction block (Lewis-Sumner syndrome)].
[Article in German]
Finsterer J, Mamoli B
Neurologische Abteilung, Neurologisches Krankenhaus Rosenhugel, Wien.
Multifocal motor neuropathy, which mimics lower motor neuron disease, is a rare and curious
demyelinating neuropathy characterised by slowly progressive, asymmetric limb weakness within
the distribution of individual peripheral nerves, wasting, cramps, fasciculations and rare sensory
involvement, but without upper motor neuron signs. The cardinal feature and primary
pathophysiological basis for the weakness is the multifocal motor conduction block which remains
stable for years at the same site and is confined to motor axons. It is defined as > 50% reduction
in both the CMAP and the negative peak area on proximal stimulation, as compared with the distal
stimulus response without any change in the negative peak duration. Nerves at the site of the
conduction block show demyelination, endoneural edema, rudimentary onion bulbs and
lymphocytic inflammation. Sensory nerves may show mild demyelination, axon loss and
lymphocytic inflammation. The majority of patients shows elevated titers of anti-glycolipid
antibodies, which may block the Na+ channels, produce demyelination or interfere with
remyelination. However, their role in the pathogenesis of multifocal motor neuropathy remains
uncertain. Multifocal motor neuropathy is regarded as the predominantly motor variant of chronic
inflammatory demyelinating polyneuropathy and can be treated best with immunoglobulins and
cyclophosphamide.
Rinsho Shinkeigaku 1999 Jan;39(1):107-9
Related Articles, Books
[Diagnosis and treatment of multifocal motor neuropathy (Lewis-Sumner)].
[Article in Japanese]
Kaji R
Department of Neurology, Kyoto University Hospital.
[Record supplied by publisher]
We made a retrospective long-term follow-up study of 25 patients with multifocal motor
neuropathy (Lewis-Sumner). The diagnosis was based upon criteria modified from those of
AAEM (Sumner 1997). The electrophysiological findings indicating conduction block or focal
demyelinative lesions were more diagnostic than anti-GM 1 antibody titers, which were elevated in
only 40% of these patients. Demonstration of definite conduction block was not always possible in
those patients who responded favorably to intravenous immunoglobulins (IVIg), whereas indirect
pieces of evidence such as F-wave abnormalities or focal conduction delay or dispersion were
equally helpful. IVIg had superior outcome to cyclophosphamide, which sometimes caused serious
adverse effects. Three patients with severe axonal involvement showed elevated monospecific
antibodies to GalNAc-GD1a.
PMID: 10377829
: Muscle Nerve 2000 Oct;23(10):1472-87
Related Articles, Books, LinkOut
Electrophysiological features of inherited demyelinating neuropathies: A
reappraisal in the era of molecular diagnosis.
Lewis RA, Sumner AJ, Shy ME
Department of Neurology, Wayne State University School of Medicine, UHC 8D, 4201 St.
Antoine, Detroit, Michigan, USA.
[Medline record in process]
The observation that inherited demyelinating neuropathies have uniform conduction slowing and
that acquired disorders have nonuniform or multifocal slowing was made prior to the identification
of mutations in myelin-specific genes which cause many of the inherited disorders involving
peripheral nerve myelin. It is now clear that the electrophysiological aspects of these disorders are
more complex than previously realized. Specifically, certain mutations appear to induce
nonuniform slowing of conduction which resemble the findings in acquired demyelinating
neuropathies. It is clinically important to recognize the different electrodiagnostic patterns of the
various inherited demyelinating neuropathies. In addition, an understanding of the relationship
between mutations of specific genes and their associated neurophysiological findings is likely to
facilitate understanding of the role of these myelin proteins in peripheral nerve function and of how
abnormalities in myelin proteins lead to neuropathy. We therefore review the current information
on the electrophysiological features of the inherited demyelinating neuropathies in hopes of
clarifying their electrodiagnostic features and to shed light on the physiological consequences of
the different genetic mutations. Copyright 2000 John Wiley & Sons, Inc.
PMID: 11003782
Muscle Nerve 1999 May;22(5):560-6
Related Articles, Books, LinkOut
Multifocal acquired demyelinating sensory and motor neuropathy: the
Lewis-Sumner syndrome.
Saperstein DS, Amato AA, Wolfe GI, Katz JS, Nations SP, Jackson CE, Bryan WW, Burns
DK, Barohn RJ
Department of Neurology, University of Texas Southwestern Medical Center, Dallas, USA.
[Record supplied by publisher]
We report 11 patients with multifocal acquired demyelinating sensory and motor (MADSAM)
neuropathy, defined clinically by a multifocal pattern of motor and sensory loss, with nerve
conduction studies showing conduction block and other features of demyelination. The clinical,
laboratory, and histological features of these patients were contrasted with those of 16 patients
with multifocal motor neuropathy (MMN). Eighty-two percent of MADSAM neuropathy patients
had elevated protein concentrations in the cerebrospinal fluid, compared with 9% of the MMN
patients (P < 0.001). No MADSAM neuropathy patient had elevated anti-GM1 antibody titers,
compared with 56% of MMN patients (P < 0.01). In contrast to the subtle abnormalities described
for MMN, MADSAM neuropathy patients had prominent demyelination on sensory nerve biopsies.
Response to intravenous immunoglobulin treatment was similar in both groups (P = 1.0).
Multifocal motor neuropathy patients typically do not respond to prednisone, but 3 of 6 MADSAM
neuropathy patients improved with prednisone. MADSAM neuropathy more closely resembles
chronic inflammatory demyelinating polyneuropathy and probably represents an asymmetrical
variant. Given their different clinical patterns and responses to treatment, it is important to
distinguish between MADSAM neuropathy and MMN.
Comment in:
Muscle Nerve. 1999 Dec;22(12):1738-9
Muscle Nerve. 1999 Dec;22(12):1739-40
Muscle Nerve. 1999 May;22(5):557-9
PMID: 10331353
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