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Rochester, MN, United States

Kazamel M.,Mayo Medical School | Dyck P.J.,Peripheral Neuropathy Research Laboratory
Prosthetics and Orthotics International | Year: 2015

Background: Diabetes mellitus is among the most common causes of peripheral neuropathy worldwide. Sensory impairment in diabetics is a major risk factor of plantar ulcers and neurogenic arthropathy (Charcot joints) causing severe morbidity and high health-care costs. Objective: To discuss the different patterns of sensory alterations in diabetic neuropathies and their anatomical basis. Study design: Literature review. Methods: Review of the literature discussing different patterns of sensory impairment in diabetic neuropathies. Results: The different varieties of diabetic neuropathies include typical sensorimotor polyneuropathy (lower extremity predominant, length-dependent, symmetric, sensorimotor polyneuropathy presumably related to chronic hyperglycemic exposure, and related metabolic events), entrapment mononeuropathies, radiculoplexus neuropathies related to immune inflammatory ischemic events, cranial neuropathies, and treatment-related neuropathies (e.g. insulin neuritis). None of these patterns are unique for diabetes, and they can occur in nondiabetics. Sensory alterations are different among these prototypic varieties and are vital in diagnosis, following course, treatment options, and follow-up of treatment effects. Conclusions: Diabetic neuropathies can involve any segment of peripheral nerves from nerve roots to the nerve endings giving different patterns of abnormal sensation. It is the involvement of small fibers that causes positive sensory symptoms like pain early during the course of disease, bringing subjects to physician's care. Copyright © 2014 The International Society for Prosthetics and Orthotics.

Dyck P.J.,Peripheral Neuropathy Research Laboratory | Carter R.E.,Mayo Medical School | Litchy W.J.,Peripheral Neuropathy Research Laboratory
Muscle and Nerve | Year: 2011

Introduction: In this study we aimed to determine which criteria are valid for nerve conduction (NC) diagnosis of typical diabetic sensorimotor polyneuropathy (DSPN). Methods: Eight criteria were assessed from among diabetes databases, the Rochester Diabetic Neuropathy Study (RDNS, N = 456), and in healthy subjects (RDNS-HS, N = 330). Results: In the RDNS, the most frequent abnormal attributes (≤2.5th/≥97.5th percentile) are: fibular motor nerve conduction velocity (MNCV; 26.3%); sural sensory nerve conduction velocity (SNAP; 25.4%); tibial MNCV (24.8%); ulnar MNCV (21.3%); fibular F latency (16.9%); and ulnar F latency (16.0%). Normal deviate (from percentiles) composite scores of NC included: representative of neurophysiological abnormalities; sensitive and specific for diagnosis and useful for epidemiological surveys; randomized trials; and medical practice. By contrast, abnormality of one or more attributes in any nerve or abnormally of two most sensitive attributes performed poorly. Conclusions: Composite sum scores of normal deviates (from percentiles corrected for applicable variables) of sensitive NC attributes and with modifications, RDNS and AAN criteria performed acceptably for diagnosis of DSPN. © 2011 Wiley Periodicals, Inc.

Chahin N.,Peripheral Neuropathy Research Laboratory | Temesgen Z.,Mayo Medical School | Kurtin P.J.,Mayo Medical School | Spinner R.J.,Mayo Medical School | Dyck P.J.B.,Peripheral Neuropathy Research Laboratory
Muscle and Nerve | Year: 2010

Diffuse infiltrative lymphocytosis syndrome (DILS) is a hyperimmune reaction against HIV. It leads to MHC-restricted clonal expansion of CD8 T cells characterized by circulating CD8 hyperlymphocytosis and CD8 T-cell infiltration in organs. Our patient presented with painful lumbosacral radiculo-plexus neuropathy and tested positive for HIV. Nerve biopsy showed large collections of CD8 lymphocytes suspicious for lymphoma. Symptoms, signs, and repeat biopsy improved with antiretroviral treatment. The presentation and treatment response suggest that this case is localized DILS. © 2009 Wiley Periodicals, Inc.

Tracy J.A.,Peripheral Neuropathy Research Laboratory | Dyck P.J.B.,Peripheral Neuropathy Research Laboratory
Journal of the Peripheral Nervous System | Year: 2011

Twenty-four patients, all of whom were exposed to aerosolized porcine brain tissue through work-place environment (abattoir), developed a syndrome of immune-mediated polyradiculoneuropathy; three also had central nervous system manifestations (transverse myelitis, meningoencephalitis, and aseptic meningitis). Patients had characteristic electrophysiological findings of very distal and proximal conduction slowing (prolonged distal and F-wave latencies, regions where the blood-nerve barrier is the most permeable) and all patients' serum contained a novel IgG immunofluorescence pattern. Nerve pathology, when available, showed mild changes of segmental demyelination, axonal degeneration, and inflammatory changes. Patients had meaningful improvement of symptoms and electrophysiologic findings with immune therapy and with removal of exposure to aerosolized brain tissue. We postulate that this outbreak is an auto-immune polyradiculoneuropathy triggered by occupational exposure to multiple aerosolized porcine neural tissue antigens that result in neural damage where the blood-nerve barrier is the least robust. © 2011 Peripheral Nerve Society.

Engelstad J.K.,Peripheral Neuropathy Research Laboratory | Taylor S.W.,Peripheral Neuropathy Research Laboratory | Witt L.V.,Peripheral Neuropathy Research Laboratory | Hoebing B.J.,Peripheral Neuropathy Research Laboratory | And 6 more authors.
Neurology | Year: 2012

Objectives: Our first objective was to explore the value of estimating 95% confidence intervals (CIs) of epidermal nerve fibers (ENFs)/mm for number of sections to be evaluated and for confidently judging normality or abnormality. Our second objective was to introduce a new continuous measure combining nerve conduction and ENFs/mm. Methods: The 95%CI studieswere performed on 1, 1-2, 1-3 - - - 1-10 serial skip sections of 3-mm punch biopsies of leg and thigh of 67 healthy subjects and 23 patients with diabetes mellitus. Results: Variability of differences of ENFs/mm counts (and 95% CIs) from evaluation of 1, 1-2, 1-3 - - - 1-9 comparedwith1-10 serial skip sections decreased progressively without a break point with increasing numbers of sections evaluated. Estimating 95% CIs as sections are evaluated can be used to judge how many sections are needed for adequate evaluation, i.e., only a fewwhen counts and 95% CIs are well within the range of normality or abnormality and more when values are borderline. Also provided is a methodology to combine results of nerve conduction and ENFs/mm as continuous measures of normality or abnormality. Conclusion: Estimating 95% CIs of ENFs/mm is useful to judge how many sections should be evaluated to confidently declare counts to be normal or abnormal. Also introduced is a continuous measure of both large-fiber (nerve conduction) and small-fiber (ENFs/mm) normal structures/functions spanning the range of normality and abnormality for use in therapeutic trials. © 2012 American Academy of Neurology.

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