Isaacs' syndrome is a rare neuromuscular disorder that is characterized by progressive muscle stiffness; continuously contracting or twitching muscles
(myokymia); and diminished reflexes. Signs and symptoms generally develop between ages 15 and 60, with most people experiencing symptoms before age 40. Although the exact underlying cause is unknown, there appear to be hereditary and acquired (non-inherited) forms of the condition. Treatment is based on the sign and symptoms present in each person.
What are the signs and symptoms of Isaacs' syndrome?
The signs and symptoms of Isaacs' syndrome generally develop between ages 15 and 60, with most people showing symptoms before age 40. Although the symptoms can vary, affected people may experience:
Progressive stiffness, cramping and weakness
Muscle twitching with a rippling appearance (myokymia)
These symptoms generally persist throughout the day, even during sleep or when under general anesthesia. Speech and breathing may also be affected if the muscles of the throat are involved. Smooth muscles and cardiac (heart) muscles typically are spared.
Last updated: 9/16/2015
How might Isaacs' syndrome be treated?
The treatment of Isaacs' syndrome is based on the signs and symptoms present in each person. For example, anticonvulsant medications such as phenytoin and carbamazepine may be prescribed to relieve stiffness, muscle spasms, and pain. Plasma exchange may provide short-term relief for people with some forms of acquired Isaacs' syndrome. Plasma exchange is a method by which whole blood is removed from the body and processed so that the red and white blood cells are separated from the plasma (liquid portion of the blood). The blood cells are then returned to the patient without the plasma, which the body quickly replaces. If there is no response or poor response to plasma exchange, some studies suggest that intravenous infusions of immunoglobulins (IvIg therapy) may be beneficial.
Last updated: 9/17/2015
What is the long-term outlook for people with Isaacs' syndrome?
The long-term outlook (prognosis) for people with Isaacs' syndrome varies and largely depends on the underlying cause. In general, there is no cure for the condition although it is generally not fatal.
Last updated: 9/17/2015
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