SUBACUTE DIABETIC PROXIMAL NEUROPATHY

Objective: To evaluate the clinical, electrophysiologic, autonomic, an d neuropathologic characteristics and the natural history of subacute diabetic proximal neuropathy and its response to immunotherapy, Materi al and Methods: For the 12-year period from 1983 to 1995, me conducted a retrospective review of medical records of Mayo Clinic patients wit h diabetes mho had subacute onset and progression of proximal weakness , The responses of treated versus untreated patients mere compared sta tistically, Results: During the designated study period, 44 patients w ith subacute diabetic proximal neuropathy were encountered, Most patie nts mere middle-aged or elderly, and no sex preponderance mas noted, T he proximal muscle weakness often was associated with reduced or absen t lower extremity reflexes, Associated weight loss was a common findin g, Frequently, patients had some evidence of demyelination on nerve co nduction studies, but it invariably was accompanied by concomitant axo nal degeneration, The cerebrospinal fluid protein concentration was us ually increased, Diffuse and substantial autonomic failure was general ly present, In most cases, a sural nerve biopsy specimen suggested dem yelination, although evidence of an inflammatory infiltrate was less c ommon, Of 12 patients who received treatment (with prednisone, intrave nous immune globulin, or plasma exchange), 9 had improvement of their conditions, but 17 of 29 untreated patients (59%) with follow-up also eventually had improvement, albeit at a much slower rate, Improvement was usually incomplete, Conclusion: We suggest that the entity of sub- acute diabetic proximal neuropathy is an extensive and severe variant of bilateral lumbosacral radiculoplexopathy, with some features sugges tive of an immune-mediated cause, It differs from chronic inflammatory demyelinating polyradiculoneuropathy in that most cases have a more r estricted distribution and seem to be monophasic and self-limiting, Th e efficacy of immunotherapy is unproved, but such intervention may be considered in the severe and progressive cases or ones associated with severe neuropathic pain.