[Idiopathic lumbosacral plexopathy].

Introduction: Lumbosacral plexopathy is the equivalent in the lower limbs of neuralgic amyotrophy (also known as Parsonage-Turner syndrome) in the upper limbs. It is well-known in patients with diabetes mellitus, when it is known as Bruns-Garland syndrome.

Case: We report the case of a 47-year-old woman who developed a unilateral neuropathy of the leg, neither radicular nor truncal in origin. The slow continuous improvement was not affected by any of the treatments administered.

Discussion: Lumbosacral plexopathy is characterized by intense pain in one or both legs, associated with motor and sensory deficits. Recovery is usually slow (6 to 36 months) and often incomplete. The electrodiagnostic examination shows important acute motor and sensory axonal loss, characterized by denervation and low-amplitude sensory action potential. Treatment generally combines analgesics with narcotic agents, neuropathic pain medication, short-term corticosteroids, and rehabilitation. In the most severe cases, long-term corticosteroids and other immunosuppressive agents may be required. This diagnosis cannot be reached until all other radicular, plexal and truncal origins have been ruled out.