Multifocal motor neuropathy presenting with respiratory failure.

Multifocal motor neuropathy is a disorder characterized by slowly progressive asymmetrical limb weakness and multiple motor conduction blocks. We report a 56-year-old woman with this disorder who presented unusually with respiratory failure and who initially had absent responses to phrenic nerve stimulation bilaterally. The mechanism of the patient's respiratory failure may have been chronic conduction blocks in the phrenic nerves leading to diaphragmatic weakness.