A Case of Hemi-Isaac's Syndrome

The document describes a rare case of Isaac's syndrome with symptoms limited to the left side of the body in a 25-year-old man. The patient experienced abnormal muscle twitching and stiffness on the left side for 6 years, with associated hair loss and skin changes. Electrophysiological studies showed giant F waves and myokymic and neuromyotonic discharges, suggesting peripheral nerve hyperexcitability. Despite negative results for autoimmune and paraneoplastic antibodies, the patient responded well to treatment with intravenous methylprednisolone and plasmapheresis, supporting an autoimmune etiology. This case is notable as the first reported instance of hemi-Isaac's syndrome, a variant of acquired neuromyotonia with symptoms affecting only one side of the body. The patient's improvement after immunomodulatory treatment further suggests an autoimmune basis for the condition.