Citations

Abstract Objectives: Mild inflammatory diabetic neuropathies (IDNs) overlap with diabetic sensorimotor neuropathy (DPN) in clinical presentation and electrophysiological and laboratory tests. This study is to determine whether IDN can be differentiated from DPN by clinical features, electrophysiological, pathological, or laboratory tests. Methods: Suspected IDN cases were identified by a subacute onset and progressive sensory or motor neuropathy in patients with diabetes. Results: IDN occurred earlier in the course of diabetes mellitus and had higher prevalence of limb weakness, walking difficulty, and more severe electrophysiological abnormalities suggesting both demyelination and axonal loss. Sensory nerve biopsies in IDN showed perivascular inflammatory infiltrates, decreased fiber density, increased demyelination, and axonal degeneration. Most patients with IDN improved with immunotherapy. Conclusions: Features that favor IDN over DPN are limb weakness, more severe nerve conduction abnormalities, inflammatory infiltrates on nerve biopsy, and a favorable response to immunotherapy. A nerve biopsy can help establish an inflammatory cause.

ABSTRACTIntroduction: For sequential and somatotopic assessment of small fiber neuropathy, heat pain (HP) tests of hypoalgesia might be used instead of decreased counts of epidermal nerve fibers (ENFs), but then healthy subject reference values of HP thresholds are needed. Methods: Using the Computer Assisted Sensation Evaluator IVc system, HP thresholds of hypoalgesia were estimated for 10 unilateral sites and counts of ENFs for 4 of them in healthy subjects. Results: In healthy subjects, small but statistically significant differences of both HP thresholds of hypoalgesia and counts of ENFs were observed among tested sites. Significant correlations between HP thresholds and counts of ENFs were not found. Discussion: For the studied somatotopic sites, we provide ≥95th and ≥99th percentile reference limits for HP 0.5 and 5 of 1–10 HP thresholds of hypoalgesia and decreased counts of ENFs at ≤5th and ≤1st percentile levels. Muscle Nerve 58: 509–516, 2018

ABSTRACTIntroduction: Multifocal motor neuropathy (MMN) is a motor only, asymmetric onset neuropathy that is relatively treatment‐refractory compared with classic chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy. Methods: We reviewed 35 patients seropositive for GM1 (monosialo‐asialo [immunoglobulin M, IgM; immunoglobulin G, IgG]) and/or GD1b (disialo [IgG, IgM]) autoantibodies having MMN, classic CIDP, or MADSAM. Immune‐treatment responsiveness and clinical course was compared with antibody negative disease controls. Results: Seventy‐nine percent of seropositives with an initial diagnosis of MMN were immunotherapy responsive compared with 46% of seronegatives (P = 0.045). Eight ganglioside antibody positive MMN patients of 19 (42%) developed sensory findings consistent with MADSAM compared with 3 of 41 (7%) seronegative MMN patients (P = 0.003). MMN and MADSAM patients with ganglioside antibody positivity had more sustained treatment responses (P = 0.03). Discussion: Patients initially diagnosed with MMN seropositive for diverse GM1 autoantibodies appear more likely to have sustained treatment response and evolution to MADSAM. Muscle Nerve 57: 1000–1005, 2018

ABSTRACTIntroduction: In polyradiculoneuropathy‐organomegaly‐endocrinopathy‐monoclonal protein‐skin changes (POEMS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), limb nerve conduction studies (NCSs) are limited in identifying demyelination and in detecting treatment effects in severely affected patients. Blink R1 latency may improve these assessments. Methods: POEMS and CIDP patients who had undergone NCS and blink reflex were identified. Correlations among R1 latency, limb NCS, and neuropathy impairment scores (NIS) were compared. Results: Among 182 patients (124 POEMS, 58 CIDP) who were identified, R1 prolongation (>13 ms) occurred in 64.3% (65.3% POEMS, 62.1% CIDP). R1 prolongation correlated with more severely affected NCS in both POEMS (ulnar CMAP 2.6 mV vs. 4.5 mV, P = 0.001) and CIDP (2.0 mV vs. 6.1 mV, P < 0.001). In severely affected patients (ulnar CMAP ≤0.5 mV [10%:18/182]), R1 (>13 ms) helped establish demyelination. In 31 patients (16 POEMS, 15 CIDP), the R1 latency changes were concordant with NIS changes in 94% of patients with POEMS and 60% of patients with CIDP. Discussion: Blink R1 latencies are valuable in defining demyelination and detecting improvement in severely affected POEMS and CIDP patients. Muscle Nerve 57: E8–E13, 2018