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-year-old 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.

Distal Acquired Demyelinating Symmetric Neuropathy Associated with Decreased Electrical Excitability of the Femoral Nerves.

Introduction: There are many phenotypic variants of chronic inflammatory demyelinating polyneuropathy. Methods:An Ancient Greek aryvallos painted c. 480-450 BC, now on display at the Louvre museum, was meticulously studied regarding its painted surface, which presents an outpatient clinic in Ancient Greece. Other Ancient Greek works of art presenting medical activities have been also evaluated in order to reach informed conclusions regarding medical practice of that period. Case report: We report a rare case of the distal phenotype of chronic inflammatory demyelinating polyneuropathy with a subacute onset and rapidly progressive course. A 58-year-old male had distal, symmetric, predominantly motor impairment without ataxia and tremor. After a three-month duration of the disease, the patient had already complete paresis of the feet with absence of compound muscle action potentials (CMAPs) over the feet and lower leg muscles, but preserved proprioception and sural sensory nerve action potential. Cerebrospinal fluid protein level was elevated to 3.4 g/L. Demyelinating neuropathy was predominantly in the proximal segment of the nerves. Low amplitude of CMAPs was recorded hardly over the vastus medialis and rectus femoris muscles, while weakness and atrophy in these muscles were not. The patient was refractory to treatment. He died three years after disease onset. Conclusion:We described a new clinical-electrophysiological phenomenon, which was characterized as a decrease in the evoked electrical excitability at the femoral nerve stimulation site (decreased CMAP), while the natural physiological conduction of the impulse from the motor neuron to the muscle was not blocked (preserved muscle strength).

Radial motor nerve conduction studies in the upper arm.

INTRODUCTION: The main goal of this study was to determine the contribution of the anterior forearm muscles to the compound muscle action potential (CMAP) recorded from the extensor digitorum (ED) after proximal stimulation. METHODS: Twenty-one healthy volunteers and 114 patients with compressive and traumatic radial neuropathies were examined. Stimulation was carried out at six different points: distal third of the upper arm; Erb's point; axilla; medial upper arm; antecubital fossa; and ulnar groove. RESULTS: In the control group, Erb's CMAP area was significantly greater than the distal CMAP area. In compressive neuropathy, there was conduction block, but no change in conduction velocity. There were no differences in Erb's CMAP latencies between the control group and the neuropathies group. DISCUSSION: CMAPs recorded over the ED with stimulation at the brachial plexus represent the sum of the motor unit action potentials of the posterior and anterior forearm muscles.