[Immune-mediated neuropathies: indications and value of nerve biopsy]

Diagnostic value of nerve biopsy in the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) has been widely discussed and indication has markedly decreased since 20 years. Diagnosis of CIDP is usually based on clinical features (progressive or relapsing course, symmetrical motor and sensory neuropathy in arms and legs, hypo or areflexia usually involve all four limbs), raised CSF protein concentration and nerve conduction studies consistent with demyelination. Several electrophysiological criteria for CIDP have been proposed. We presented a case of sensory-motor neuropathy with examination compatible with CIDP. Cerebrospinal fluid protein content has been slightly elevated. Electrophysiological criteria have been lacking due to absence of recorded compound motor action potential or sensory nerve action potential in lower limbs and absence of demyelination features in upper limbs. Sural nerve biopsy has allowed to show significant demyelination on microscopic and teased nerve fibers analysis. A diagnosis of CIDP has been kept and immunomodulatory treatment has been discussed. Intravenous immune globulin treatment has been effective in this patient. Nerve biopsy stay useful for confirmation of CIDP in front of clinical features compatible with the diagnosis but without usual biological and electrophysiological criteria. The confirmation of diagnosis is significant and can lead to effective treatment.