Immunotherapy for idiopathic lumbosacral plexopathy

Jeroen van Eijk, Yee Cheun Chan, James W Russell

Idiopathic lumbosacral plexopathy (ILSP), also called lumbosacral plexitis or non-diabetic lumbosacral (radiculo)plexus neuropathy is a rare clinical entity. The core features are (sub)acute, severe, asymmetrical leg pain, followed by asymmetrical multifocal weakness and atrophy in the subsequent weeks or months. Sensory symptoms include paresthesias, hypesthesia, allodynia, and autonomic dysfunction. ILSP generally runs a monophasic and self limiting course. Recovery starts slowly over months to several years and is nearly always incomplete. Some studies suggest that the condition has an immune-mediated etiology. Biopsies of distal cutaneous nerve segments have shown features suggestive of an inflammatory microvasculitis causing ischemic damage of the nerves. The clinical and pathological findings are similar to those found in diabetic lumbosacral plexus neuropathy and suggest that inflammation may form part of the final common pathway in both conditions.