Isaacs syndrome involves overactivity of the nerves that stimulate muscle fibers. It causes progressive muscle stiffness, continuous muscle quivering and twitching, and cramping.
In people with Isaacs syndrome, muscles, particularly those in the arms and legs, continually quiver and twitch, moving like a bag of worms, and often become progressively stiffer.
Doctors diagnose Isaacs syndrome based on symptoms and results of electromyography and nerve conduction studies.
(See also Overview of the Peripheral Nervous System.)
Isaacs syndrome is rare. It appears to start in the peripheral nerves and to be caused by an antibody that attacks a specific part of the cell membrane.
Isaacs syndrome may occur in people with other disorders, such as cancer, myasthenia gravis, thymomas (tumors of the thymus gland), Hashimoto thyroiditis, vitamin B12 deficiency, celiac disease, and systemic rheumatic diseases. It can also be inherited.
Symptoms of Isaacs Syndrome
Muscles, particularly those in the arms and legs, continually quiver and twitch, moving like a bag of worms. This symptom is called myokymia. Muscle spasms and cramps may intermittently occur in the hands and feet. Muscles often become progressively stiffer and take a long time to relax after they have been contracted. Sweating may be increased.
Diagnosis of Isaacs Syndrome
Electromyography and nerve conduction studies
The diagnosis of Isaacs syndrome is based on symptoms and results of electromyography and nerve conductions studies, which show characteristic abnormalities.
Treatment of Isaacs Syndrome
Immune globulin and plasma exchange
Symptoms of Isaacs syndrome can be relieved by antiseizure medications
People may also benefit from immune globulin (a solution containing many different antibodies collected from a group of donors), given by vein (intravenously), or plasma exchange (filtering of toxic substances, including abnormal antibodies, from the blood).
