Severe Paraproteinemic Demyelinating Neuropathy With Impaired Excitability of the Distal Segments of the Peripheral Nerves

Abstract

We report clinical and detailed nerve conduction findings in case of polyneuropathy associated with kappa light chains monoclonal gammopathy of undetermined significance with progression to lymphoproliferative disorder. A 55-yearold man had a predominantly distal, chronic (5 years duration), slowly progressive, symmetric, predominantly sensory impairment with sensory ataxia, and mild weakness. M protein was identified by serum protein electrophoresis. The kappa/lambda ratio of free light chains was significantly elevated to 11.96. The cerebrospinal fluid protein level was elevated at 3.5 g/L. This case study has revealed 2 unusual electrophysiological phenomena-a very unusual prolongation of distal motor latencies of compound muscle action potentials (CMAP) up to 86.5 ms and impaired excitability of the distal segments of the peripheral nerves. The distal CMAP areas were considerably lower compared with the proximal CMAP areas. Radiography of the skull revealed osteolytic lesions.

Significance of A-waves in Isolated Calf Pain as a Manifestation of Radicular Pain During F-wave Studies: A Case Report

“…Currently, there are no recommendations on A-wave interpretation, rather only their presence or absence if described routinely [13]. They have been found in different neurogenic disorders [5,6,[14][15][16]. A-waves are heterogeneous and can be caused by several pathophysiologic mechanisms, such as myo-or trans-axonal ephaptic transmission from one axon to another, an extra-axonal discharge elicited by an afferent action potential, ectopic discharge, and collateral sprouting during axonal regeneration [6,13,17].…”