Pure motor chronic inflammatory demyelinating polyneuropathy

We describe four patients affected by chronic inflammatory demyelinating po lyneuropathy (CIDP) in a pure motor form. Selective involvement of motor fi bers was suggested by the absence of sensory symptoms, normal sensation at neurological examination and normal findings on electrophysiological testin g of sensory fibres and sural nerve biopsy. The onset of the disease occurr ed at a young age (3-29 years) and the clinical course was relapsing-remitt ing. Over a followup periode of 1.5-14 years, periodical clinical and elect rophysiological examinations showed that selective involvement of motor fib ers remained a constant feature. Electromyography and nerve conduction stud ies continued to show a purely demyelinating neuropathy without signs of ax onal impairment. All patients were steroid-unresponsive, whereas they consi derably improved after being treated with immunoglobulins. Two patients wer e treated with interferon alpha and showed a good response. In conclusion, the occurrence in our four patients of pure motor involvement over a long p eriod of time during which several relapses occurred, suggests that pure mo tor CIDP may represent the result of a specific immunological process rathe r than of a random distribution of inflammation throughout peripheral nerve s.