MASSIVE NERVE ROOT ENLARGEMENT IN CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY

Objective-To report three patients with chronic inflammatory demyelina ting polyneuropathy (CIDP) presenting with symptoms suggestive of cerv ical (one patient) and lumbar root disease. Methods-Nerve conduction s tudies, EMG, and nerve biopsy were carried out, having found the nerve roots to be very enlarged on MRI, CT myelography, and at surgery. Res ults-Clinically, peripheral nerve thickening was slight or absent. Sub sequently one patient developed facial nerve hypertrophy, This was mis taken for an inner ear tumour and biopsied, with consequent facial pal sy. Neurophysiological tests suggested a demyelinating polyneuropathy. Sural nerve biopsy showed in all cases some loss of myelinated fibres , inflammatory cell infiltration, and a few onion bulbs. Hypertrophic changes were much more prominent on posterior nerve root biopsy in one patient: many fibres were surrounded by several layers of Schwann cel l cytoplasm. There was an excellent response to steroids in two patien ts but not in the third (most advanced) patient, who has benefited onl y marginally from intravenous immunoglobulin therapy. Conclusions-MRI of the cauda equina may be a useful adjunct in the diagnosis of CIDP.