[The diagnosis of chronic axonal polyneuropathy: the poorly understood chronic polyradiculoneuritides]

Chronic inflammatory demyelinating polyradiculoneuropathy is an autoimmune disease that target myelin sheats of peripheral nerves. Its diagnosis is often difficult to make, and a number of cases are probably not identified because of the clinical and electrophysiological heterogeneity. Typical cases associate progressive or relapsing-remitting motor and sensory deficit with increased CSF protein content and electrophysiological features of demyelination. In some cases electrophysiological studies fail to show evidence of demyelination, conventional electrophysiological diagnostic criteria are not filled yet the patient may respond to immunomodulatory treatments. In such cases, presence of clinical characteristics suggestive of CIDP (that means not compatible with a length-dependent axonal process) are critical justifying fully investigations including sural nerve biopsy. The main clinical characteristic are: a symmetric proximal and distal motor weakness predominantly affecting the lower limbs, a diffuse areflexia, a sensory deficit characterized by a preferential involvement of large fibers, an evolution which may be either chronic progressive or recurrent. Usual therapeutic agents (corticosteroids, intravenous immunoglobulins, plasma exchanges) seem to have the same efficacy whatever the electrophysiologic profile.