[Mononeuritis multiplex under the TNF-alpha inhibitor infliximab].

A 21-year-old patient with ankylosing spondylitis under treatment with the TNF-alpha inhibitor infliximab developed a multifocal, demyelinating axonal neuropathy affecting several peripheral nerves simultaneously (mononeuritis multiplex). This represents an additional rare peripheral nervous system side effect of infliximab therapy. The underlying cause is unknown. Intravenous immunoglobulin therapy (0.4 g/kg per day for five days) led to a complete regression of muscle paresis and sensory defects in this case.