Focal inflammatory neuropathies

This chapter focuses on neuropathies that present with focal involvement of nerve roots, plexus, and/or peripheral nerves associated with autoimmune and inflammatory mechanisms that present with focal involvement of nerve roots, plexus and/or peripheral nerves. The clinical presentation, diagnosis, and treatment of focal autoimmune demyelinating neuropathies, focal nonsystemic vasculitic disorders (diabetic and nondiabetic radiculoplexus neuropathies, postsurgical inflammatory neuropathy, and neuralgic amyotrophy), and focal neuropathies associated with sarcoidosis and bacterial and viral infections are reviewed.

[Atypical neuropathies associated with diabetes]

Diabetes is the leading cause of neuropathy worldwide and, due to the epidemic progression of the affection, prevalence of diabetic neuropathies will increase in the near future. Beside the typical diabetic neuropathy pattern and the common entrapment neuropathies, several unusual clinical forms have been described with either a symmetrical or an asymmetrical pattern. Treatment-induced neuropathy is an acute sensory affection most commonly related to acute glycemic control. Pain is debilitating and associated with vegetative dysfunction. Prevention is important, as resolution is often incomplete. Several patterns or asymmetrical neuropathies of inflammatory and ischemic origin were described long ago in the lower limb. They are debilitating, most often painful and require steroid treatment. Other patterns affecting the thoracolumbar region or the upper limbs or involving a painless motor deficit must be identified as specific treatments are sometimes needed. An association between diabetes and chronic inflammatory demyelinating polyneuropathy has not been demonstrated but diagnosis may be suggested due to the misleading low conduction velocities seen in classical diabetic neuropathy. Like any other patient, the diabetic patient may present a neuropathy unrelated to diabetes. To facilitate patient care, neurologists should be aware of such clinical entities.