Citations

See article on pages 141–146 in this issue.

See article on pages 643–649 in this issue.

ABSTRACTIntroductionOnion‐bulbs (OB) are concentrically layered Schwann‐cell processes, surrounding nerve fibers, occurring in both inherited and acquired demyelinating polyneuropathies. We investigated whether OB patterns (generalized, mixed, or focal) correlate with acquired or inherited neuropathies.MethodsOne hundred thirty‐one OB‐rich nerve biopsies were graded for OB pattern and inflammation without knowledge of clinical history. We classified inherited (n = 49) or acquired (n = 82) neuropathies based solely on clinical history.ResultsFifty‐one biopsies had generalized (34 inherited vs. 17 acquired, P < 0.001), 54 mixed (48 acquired vs. 6 inherited, P < 0.001), and 26 focal/multifocal (inherited [n = 9], acquired [n = 17]) OB. Inflammation occurred more frequently in acquired (n = 54) than inherited (n = 14) neuropathy (P = 0.004).DiscussionGeneralized OB correlates with inherited neuropathy; mixed OB with acquired. Inflammation occurs more in acquired neuropathy cases. OB patterns are best explained by ubiquitous Schwann‐cell involvement in inherited and multifocal Schwann‐cell involvement in acquired neuropathies and predict the electrophysiology of uniform demyelination in inherited and unequal demyelination in acquired neuropathies. Muscle Nerve 59:665–670, 2019

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