Isaacs syndrome is a rThTare acquired neuromuscular disorder characterized by peripheral nerve hyperexcitability. Symptoms involve progressive muscle pain, stiffness, and notable continuous diffuse myokymic muscle-twitching clinically consistent with neuromyotonia. There can be associated weakness, hyporeflexia, numbness, dysesthesias, and hyperhidrosis. Isaacs syndrome generally presents between ages 25–60, more commonly in men. Etiologies include autoimmune, often paraneoplastic, syndromes, typically associated with malignant thymic carcinomas. Therapeutic management involves treating the underlining malignancy, as well as using immune-mediated therapies including corticosteroids, intravenous immunoglobulin, plasma exchange, and rituximab. The long-term prognosis for patients with Isaacs syndrome varies, generally dependent on the underlying cause. While Isaacs syndrome is a chronic condition without a cure, it is generally treatable and not fatal.
Immune-mediated movement disorders, neuronal antibodies, and paraneoplastic syndromes
