Login  |  register  |  forgot home diseases and conditions communities clinicians about home > diseases and conditions >  neuropathy center > article motor and multifocal motor neuropathies pathogenesis and pathophysiology article section 6 of 14.   previous  next by rebecca e traub md and thomas h brannagan iii md the cause of weakness in motor neuropathies, and multifocal motor neuropathy in particular, is likely related to a combination of demyelination at areas of conduction block, but there is also a component of focal and generalized axonal loss. In one study of 20 patients with multifocal motor neuropathy on ivig, emg evidence of axonal loss was common, occurring in 61% of muscles tested, findings of axonal loss were the most significant determinant of muscle weakness, and conduction block was an independent determinant of axonal loss (van asseldonk et al 2006). buy viagra online nationalityinworldhistory.net/bsh-buy-cheap-viagra-online-uk-tf/ online pharmacy buy viagra from india buy cheap viagra soft generic viagra cheap generic viagra viagra online buy generic viagra buy cheap viagra viagra for sale Pathological studies of motor neuropathy are rare. In one study, nerves at the site of conduction block in 2 patients with anti-gm1 antibodies showed evidence for demyelination without inflammatory cell infiltrates (kaji et al 1993). Similar changes were seen in other patients with motor neuropathy and conduction block, although not clearly at the site of conduction block (auer et al 1989; corbo et al 1997). Another study of 7 patients with pathological specimens at the site of motor conduction block showed no signs of demyelination, but instead showed multifocal axonal degeneration (taylor et al 2004). Igm deposits at the nodes of ranvier have been seen in patients with multifocal motor conduction block and anti-gm1 antibodies (santoro et al 1990; adams et al 1993). Nerve biopsy can be helpful in making a diagnosis of motor neuropathy. Motor nerve biopsies of the obturator nerve to the gracilis muscle from patients with motor neuropathy showed an increase of regenerative clusters of small myelinated fibers, in comparison to those in patients with motor neuron disease (corbo et al 1997). Sural nerve biopsies show no abnormalities (van den bergh et al 1989; hays 1991) or show only minimal abnormalities (hays 1991; corse et al 1996). A few patients with motor neuropathy have been examined at postmortem. A patient with motor neuropathy and an igm monoclonal gammopathy was reported by rowland and colleagues (rowland et al 1982). Postmortem examination. viagra online pharmacy usa