Isaacs' Syndrome (Neuromyotonia) Associated With Peripheral Neuropathy

Isaacs's syndrome (neuromyotonia), which is characterized by peripheral nerve hyperexcitability, is a rare condition of spontaneous and continuous muscle fibre activity. This syndrome is associated with myokymia, muscle cramps and stiffness, delayed muscle relaxation after contraction, muscle weakness, and hyperhydrosis. We report two siblings with Isaacs' syndrome associated with peripheral neuropathy gait disturbance, distal muscle weakness, neuromyotonia, muscle spasms, myokymia and hyperhydrosis. In both patients, neuromyotonic discharges were recorded by needle electromyography and axonal sensorimotor peripheral neuropathy was diagnosed electrophysiologically. In this study, a rare case of Isaacs'syndrome (neuromyotonia) associated with peripheral neuropathy is emphasized.