Nonsystemic vasculitic neuropathy: update on diagnosis, classification, pathogenesis, and treatment.
ABSTRACT The primary systemic vasculitides are autoimmune disorders characterized by chronic immune responses directed against vascular structures. They commonly affect small or medium-sized vessels in the peripheral nervous system (PNS), producing vasculitic neuropathies. Some patients develop vasculitis clinically restricted to the PNS, known as nonsystemic vasculitic neuropathy (NSVN), the most commonly encountered vasculitic neuropathy in pathologically based series. Diabetic and nondiabetic radiculoplexus neuropathies are clinical variants of NSVN. NSVN is clinically similar to systemic vasculitis-associated neuropathies except for reduced severity. Patients most commonly present with progressive, stepwise pain, weakness, and numbness over multiple months. Almost all exhibit a multifocal or asymmetric, distally accentuated pattern of involvement. The most commonly affected nerves are the common peroneal nerve in the leg and the ulnar nerve in the arm. Sedimentation rate is mildly to moderately elevated in 50%; other markers of systemic inflammation are generally normal. Electrodiagnostic studies reveal a predominantly axonal, asymmetric, sensorimotor polyneuropathy, but pseudo-conduction blocks may occur. Definite diagnosis requires biopsy evidence of vascular inflammation and signs of active or remote vascular damage. In biopsies lacking definite vasculitis, the diagnosis is suspected if axonal alterations are accompanied by perivascular inflammation and such supportive features as Wallerian-like degeneration, asymmetric fiber loss, hemosiderin, vascular immune deposits, neovascularization, myofiber necrosis/regeneration, focal perineurial damage, and endoneurial purpura. NSVN preferentially affects larger epineurial arterioles. Epineurial infiltrates are composed primarily of T cells and macrophages, suggesting that cellular cytotoxicity is the primary effector mechanism. Systemic vasculitides with progressive neuropathy are usually treated with cyclophosphamide and prednisone. No randomized controlled trial of therapy has been performed in NSVN, but data from retrospective cohorts suggest that combination therapy is more effective than steroid monotherapy. Once remission has been induced, cyclophosphamide should be replaced with azathioprine or methotrexate. Refractory patients can be treated with intravenous immunoglobulin, mycophenolate, rituximab, infliximab, or alemtuzumab. Although long-term outcome is reasonably good, more than one third of patients relapse, infrequent patients die from the disease or its treatment, and still others develop chronic pain.
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ABSTRACT: Multiple mononeuropathy is an unusual form of peripheral neuropathy involving two or more nerve trunks. It is a syndrome with many different causes. We reviewed the clinical, electrophysiological and nerve biopsy findings of 14 patients who suffered from multiple mononeuropathy in our clinic between January 2009 and June 2013. Patients were diagnosed with vasculitic neuropathy (n = 6), perineuritis (n = 2), chronic inflammatory demyelinating polyradiculoneuropathy (n = 2) or Lewis-Sumner syndrome (n = 1) on the basis of clinical features, laboratory data, electrophysiological investigations and nerve biopsies. Two patients who were clinically diagnosed with vasculitic neuropathy and one patient who was clinically diagnosed with chronic inflammatory demyelinating polyradiculoneuropathy were not confirmed by nerve biopsy. Nerve biopsies confirmed clinical diagnosis in 78.6% of the patients (11/14). Nerve biopsy pathological diagnosis is crucial to the etiological diagnosis of multiple mononeuropathy.Neural Regeneration Research 01/2015; 10(1). DOI:10.4103/1673-5374.150716 · 0.23 Impact Factor
- Aktuelle Neurologie 09/2008; 35. DOI:10.1055/s-0028-1086831 · 0.32 Impact Factor
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ABSTRACT: Hyperglycemia accentuates the injury produced by anoxia both in the central and peripheral nervous system. To understand whether this is a consequence of changes in metabolic pathways produced by anoxia, the effect of the metabolic substrate used by the rat peripheral nerve on the nerve action potential (NAP) was studied in the presence and absence of anoxia. In the continuously oxygenated state, the NAP was well preserved with glucose, lactate, as well as with high concentrations of sorbitol and fructose but not β-hydroxybutyrate, acetate or galactose. With intermittent anoxia, the pattern of substrate effects on the NAP changed markedly so that low concentrations of fructose became able to support neurophysiologic activity but not high concentrations of glucose. These alterations occurred gradually with repeated episodes of anoxia as reflected by the progressive increase in the time needed for the NAP to disappear during anoxia when using glucose as substrate. This "preconditioning" effect was not seen with other substrates and an opposite effect was seen with lactate. In fact, the rate at which the NAP disappeared during anoxia was not simply related to degree of recovery after anoxia. These are distinct phenomena. For example, the NAP persisted longest during anoxia in the setting of hyperglycemia but this was the state in which the anoxic damage was most severe. Correlating the results with existing literature on the metabolic functions of Schwann cells and axons generates testable hypotheses for the mechanism of hyperglycemic damage during anoxia and lead to discussions of the role for a metabolic shuttle between Schwann cells and axons as well as a potential important role of glycogen. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.Neuroscience 11/2014; 284C:653-667. DOI:10.1016/j.neuroscience.2014.10.048 · 3.33 Impact Factor