Non-diabetic lumbosacral radiculoplexus neuropathy - Natural history, outcome and comparison with the diabetic variety

Diabetic lumbosacral radiculoplexus neuropathy (DLSRPN) (other names includ e diabetic amyotrophy) is well recognized, unlike the non-diabetic lumbosac ral radiculoplexus neuropathy (LSRPN), which has received less attention. O ur objective was to characterize the natural history and outcome of LSRPN a nd to assess whether it is similar to the diabetic variety in its symptoms, course, electrophysiological features, quantitative sensory and autonomic findings, and the underlying pathophysiology. We studied 57 patients with L SRPN and 33 patients with DLSRPN, We found that the age of onset, course, k ind and distribution of symptoms and impairments, laboratory findings and o utcomes are essentially alike. Both disorders are a lumbosacral plexus neur opathy associated with weight loss, often beginning focally or asymmetrical ly in the thigh or leg but usually progressing to involve the initially una ffected segment and the contralateral side. Both have prolonged morbidity d ue to pain, paralysis, autonomic involvement and sensory loss. In biopsied distal LSRPN nerves, we found changes similar to those found in DLSRPN-alte rations typical of ischaemic injury and of microvasculitis. The long-term o utcome was determined in 42 LSRPN patients: two had become diabetic, seven had relapsed and only three had recovered completely, although all had impr oved. We conclude that: (i) LSRPN is a subacute, asymmetrical, painful and debilitating neuropathy of the lower limbs associated with weight loss, and we think it is under-recognized; (ii) recovery from the long-term impairme nts of LSRPN is usually delayed and incomplete and only a small minority of patients develop diabetes mellitus; (iii) LSRPN mirrors the diabetic varie ty in its clinical features, course, pathological findings (ischaemic injur y from microvasculitis) and long-term outcome; and (iv) LSRPN should be set apart from chronic inflammatory demyelinating polyradiculoneuropathy and f rom systemic necrotizing vasculitis, We infer an autoimmune basis for LSRPN and emphasize the need for controlled trials of immune-modulating therapy.