Slow resolution of multifocal weakness and fasciculation

Abstract

A 25-year-old man with multifocal weakness and fasciculation was thought to have motor neuron disease. Signs progressed for 1 year, plateaued, and 3 years later resolved almost completely. There was no evidence of paraproteinemia, lymphoproliferative disorder, or vasculitis, and myelography was normal. Electrodiagnostic study disclosed multifocal, acute and chronic denervation that evolved into a picture consistent with residuals of old multifocal radiculopathy without active denervation. Prolongation of F response, absence of H-reflex, and conduction block in a proximal nerve segment suggested multifocal demyelination. A proximal motor neuropathy, perhaps demyelinating, may cause some of the benign motor neuron syndromes that simulate motor neuron disease.

Multifocal acquired demyelinating sensory and motor neuropathy: The Lewis-Sumner syndrome

“…24 They described five patients with motor and sensory symptoms. Although two similar patients were subsequently described, 19,27 most of the reports that followed the initial one described patients with purely motor multifocal neuropathies with CB, 4,9,18,20,22,32,33,34,37 and this entity became known as MMN. 34 The cases reported by Lewis et al have been considered to represent the first described cases of MMN, but these patients actually had the clinical, electrophysiological, and histological features of MADSAM neuropathy.…”

Immunotherapy in Peripheral Neuropathies

“…First reported in 1986 [65,66], MMN is a very rare disease, with a prevalence of around 0.6 per 100,000 individuals. It is a purely motor neuropathy, characterized by progressive distal asymmetric limb weakness that usually starts and predominates in the upper limbs, with minimal or no sensory impairment.…”

Multifocal Motor Neuropathy: Update on Clinical Characteristics, Pathophysiological Concepts and Therapeutic Options

“…Besides, relapsing forms of MMN showing acute deterioration, stepwise progression, as well as spontaneous remissions have occasionally been described [2,13,30]. Anecdotic reports on subacute monophasic MMN presenting with tetraparesis, preserved tendon reflexes and normal motor and sensory nerve conduction following Campylobacter jejuni infections [31,32,33] most likely reflected aberrant forms of Guillain-Barré syndrome (GBS) [34].…”

“…In contrast to MND, MMN is characterized by its mononeuritis multiplex-like distribution of muscle weakness, which is not simply asymmetric but follows distinct peripheral nerves [2,116,117,118]. Furthermore, the disease course in MMN is more protracted and bulbar symptoms are missing.…”

“…Electrophysiological examination revealed proximal multifocal persistent conduction blocks (CBs) outside the common entrapment sites. Soon afterwards, others described individuals with similar characteristics [2,3]. The term ‘multifocal motor neuropathy’ (MMN) was coined in 1988 by Pestronk et al [4] who first recognized the association of MMN with anti-GM1-IgM antibodies and the responsiveness to immune-modulating therapies.…”