Idiopathic, progressive mononeuropathy in young people
J. W. Engstrom, R. B. Layzer, R. K. Olney and M. B. Edwards
Department of Neurology, School of Medicine, University of California, San Francisco 94143-0114.
We describe six young patients with insidiously progressive, painless
weakness in the distribution of a single major lower extremity nerve. No
cause could be found despite extensive evaluation, including surgical
exploration. At the time of diagnosis, all patients had weakness and three
patients had sensory loss. In all cases, electromyography revealed a
chronic axonal mononeuropathy without conduction block or focal conduction
slowing. Magnetic resonance, computed tomographic, and ultrasound imaging
studies did not identify a region of nerve swelling, mass, or compression.
At surgical exploration, the nerve appeared atrophic in two patients,
indurated in one patient, and normal in two patients. Biopsy specimens
obtained from two abnormal nerves revealed either wallerian degeneration or
endoneurial fibrosis. The clinical features of these patients comprise an
unusual clinical entity with no known cause or treatment.
