Isaac's Syndrome

Disease: Isaac's Syndrome

Common Name: Isaac's Syndrome, neuromyotonia, Isaac-Mertens syndrome, continuous muscle fiber activity syndrome, or quantal squander syndrome

Age of Onset: Onset is between ages 15 and 60, with most individuals experiencing symptoms before age 40

Duration: chronic once acquired

Does not have a commonality between males/females or ethnic group

Cause: Isaac's Syndrome can be hereditary as well as being acquired but has unknown causes. The acquired form occasionally develops together with peripheral neuropathies or after radiation treatment, but it is more often caused by an autoimmune condition. Autoimmune-mediated Isaac's syndrome is usually caused by antibodies that bind to potassium channels on the motor nerve. Isaac's syndrome is only one of several neurological conditions that can be caused by potassium channel antibodies.

Symptoms and Prognosis: progressive muscle stiffness, continuously contracting or twitching muscles, cramping, increased sweating, and delayed muscle relaxation, occur even during sleep or when individuals are under general anesthesia. Many people also develop weakened reflexes and muscle pain, but numbness is relatively uncommon. In most people with Isaac's syndrome, stiffness is most prominent in limb and trunk muscles, although symptoms can be limited to cranial muscles. Speech and breathing may be affected if pharyngeal or laryngeal muscles are involved. There is no cure for Isaac's syndrome. The long-term prognosis for individuals with the disorder is uncertain.

Treatment Options: Anticonvulsants, including phenytoin and carbamazepine, usually provide significant relief from the stiffness, muscle spasms, and pain associated with Isaac's syndrome. Plasma exchange may provide short-term relief for individuals with some forms of the acquired disorder.

Reasearch Being Done: The NINDS supports an extensive research program of basic studies to increase understanding of diseases that affect the brain, spinal cord, muscles, and nerves. This research examines the genetics, symptoms, progression, and psychological and behavioral impact of diseases, with the goal of improving ways to diagnose, treat, and, ultimately, cure these disorders.