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- $Unique_ID{BRK03882}
- $Pretitle{}
- $Title{Isaacs' Syndrome}
- $Subject{Isaacs' Syndrome Continuous Muscle Fiber Activity Syndrome
- Neuromyotonia Quantal Squander Neuromyotonia Generalized sporadic
- Neuromyotonia Generalized familial Neuromyotonia Focal Hallervorden-Spatz
- Disease Paraplegia Hereditary Spastic Stiff Man Syndrome }
- $Volume{}
- $Log{}
-
- Copyright (C) 1991 National Organization for Rare Disorders, Inc.
-
- 758:
- Isaacs' Syndrome
-
- ** IMPORTANT **
- It is possible that the main title of the article (Isaacs' Syndrome) is
- not the name you expected. Please check the SYNONYM listing to find the
- alternate names and disorder subdivisions covered by this article.
-
- Synonyms
-
- Continuous Muscle Fiber Activity Syndrome
- Neuromyotonia
- Quantal Squander
-
- Disorder Subdivisions:
-
- Neuromyotonia, Generalized - sporadic
- Neuromyotonia, Generalized - familial
- Neuromyotonia, Focal
-
- Information on the following disorders can be found in the Related
- Disorders section of this report:
-
- Hallervorden-Spatz Disease
- Paraplegia, Hereditary Spastic
- Stiff Man Syndrome
-
- General Discussion
-
- ** REMINDER **
- The information contained in the Rare Disease Database is provided for
- educational purposes only. It should not be used for diagnostic or treatment
- purposes. If you wish to obtain more information about this disorder, please
- contact your personal physician and/or the agencies listed in the "Resources"
- section of this report.
-
- Isaacs' Syndrome is a peripheral motor neuron disorder characterized by
- muscular stiffness and cramping, particularly in the limbs. Continuous fine
- vibrating muscle movements (myokymia) can be seen. Muscle relaxation may be
- difficult especially after physical activity involving the particular
- muscle(s). These symptoms occur even during sleep.
-
- Symptoms
-
- In Isaacs' Syndrome, involuntary continuous muscle fiber activity may cause
- stiffness and delayed relaxation in the affected muscles. Continuous fine
- vibrating muscle movements (myokymia) may occur along with these symptoms.
- Walking may be difficult. Isaac's Syndrome may be generalized or focal.
- When it is focal, muscle relaxation following voluntary muscle movement is
- delayed in the affected muscle(s) so that the patient may be an unable to
- open his or her fist or eyes immediately after closing them tightly for a few
- seconds.
-
- Diagnosis of Isaacs' Syndrome is accomplished by using an instrument that
- measures electrical activity occurring in a muscle (electromyography or EMG).
- A person with Isaacs' Syndrome will register abnormal electrical activity in
- the muscle(s), and the peripheral nerves.
-
- Causes
-
- Isaacs' Syndrome is caused by abnormal nerve impulses from the peripheral
- nerves. The impulses cause continuous muscle fiber activity which may
- continue even during sleep. There are three types of Isaacs' Syndrome; each
- one develops from a different cause:
-
- In the generalized-sporadic type of Isaacs' Syndrome, intrathoracic
- malignancy such as a tumor (located between the neck and abdomen) may be the
- cause.
-
- Peripheral neuropathy may be linked with the generalized-familial type of
- Isaacs' Syndrome, which tends to occur in families. This type of Isaacs'
- Syndrome may be inherited through an autosomal dominant gene.
-
- Human traits including the classic genetic diseases, are the product of
- the interaction of two genes for that condition, one received from the father
- and one from the mother. In dominant disorders, a single copy of the disease
- gene (received from either the mother or father) will be expressed
- "dominating" the normal gene and resulting in appearance of the disease. The
- risk of transmitting the disorder from affected parent to offspring is 50%
- for each pregnancy regardless of the sex of the resulting child.
- (For more information, choose "Peripheral Neuropathy" as your search term
- in the Rare Disease Database).
-
- The focal form of Isaacs' Syndrome may occur as a result of lesions on
- the peripheral nerves. The cause of the lesions is often unknown.
-
- Affected Population
-
- Isaacs' Syndrome is a rare disorder affecting males and females of all ages
- in equal numbers.
-
- Related Disorders
-
- Symptoms of the following disorders can be similar to those of Isaacs'
- Syndrome. Comparisons may be useful for a differential diagnosis:
-
- The patient with Hallervorden-Spatz Disease may develop symptoms
- resembling dystonia (a slow, steady muscle contraction distorting limbs,
- neck, face, mouth or trunk into certain positions), muscular rigidity
- (uncontrolled tightening of the muscles), and choreoathetosis (spontaneous,
- non-repetitive, slow writhing movements, usually of the extremities). Muscle
- spasms are present in one third of affected individuals. Less common
- symptoms are dysarthria (difficulty in speaking), mental retardation, facial
- grimacing, dysphasia (impaired speech), muscle atrophy (shrinking muscles)
- and seizures. Symptoms vary in different individuals. (For more information
- on these disorders, choose "Hallervorden-Spatz" or "Dystonia" as your search
- terms in the Rare Disease Database).
-
- Initial symptoms of Hereditary Spastic Paraplegia usually include
- weakness, muscle spasms, and stiffness of the legs. Leg muscles may contract
- or a heel deformity may occur making walking difficult. Speech disturbances
- can also appear. Difficulty in swallowing, exaggeration of tendon reflexes
- and general muscle weakening may develop as this disorder progresses.
- Symptoms can range from mild to severe depending upon the mode of inheritance
- (dominant or recessive genes), and the degree to which the nerves are
- compressed or damaged. (For more information on this disorder, choose
- "paraplegia" as your search term in the Rare Disease Database).
-
- Stiff Man Syndrome is a very rare neurological disorder. It is
- characterized by progressive rigidity and spasms of the voluntary muscles of
- the neck, trunk, shoulders, and proximal extremities. It is caused by
- abnormal nerve activity most likely in the central, rather than peripheral,
- nervous system. The electrical activity measured by the EMG may begin in the
- spinal cord, rather than the peripheral nerves. (For more information on
- this disorder, choose "stiff-man" as your search term in the Rare Disease
- Database).
-
- Therapies: Standard
-
- Isaacs' Syndrome may be treated with anticonvulsant drugs such as phenytoin
- or carbamazepine, which may stop the abnormal impulses and prevent the
- symptoms from reoccurring.
-
- Genetic counseling may be of benefit for patients and their families with
- inherited forms of Isaacs' Syndrome. Other treatment is symptomatic and
- supportive.
-
- Therapies: Investigational
-
- Research on Isaacs' Syndrome indicates that inhalation of oxygen may help
- muscle relaxation and hand spasms but not myokymia (continuous fine vibrating
- muscle movements). These movements are usually found to be relieved with the
- anticonvulsant drug phenytoin.
-
- Surgery, entailing motor nerve block and/or block of the afferent
- sensitive fibers (which send impulses to the brain or spinal cord), may help
- some patients when drug therapies are ineffective.
-
- This disease entry is based upon medical information available through
- June 1991. Since NORD's resources are limited, it is not possible to keep
- every entry in the Rare Disease Database completely current and accurate.
- Please check with the agencies listed in the Resources section for the most
- current information about this disorder.
-
- Resources
-
- For more information on Isaacs' Syndrome, please contact:
-
- National Organization for Rare Disorders (NORD)
- P.O. Box 8923
- New Fairfield, CT 06812-1783
- (203) 746-6518
-
- The National Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
- Information Clearinghouse
- Box AMS
- Bethesda, MD 20892
- (301) 495-4484
-
- For genetic information and genetic counseling referrals:
-
- March of Dimes Birth Defects Foundation
- 1275 Mamaroneck Avenue
- White Plains, NY 10605
- (914) 428-7100
-
- Alliance of Genetic Support Groups
- 35 Wisconsin Circle, Suite 440
- Chevy Chase, MD 20815
- (800) 336-GENE
- (301) 652-5553
-
- References
-
- CECIL TEXTBOOK OF MEDICINE, 18th Ed.: James B. Wyngaarden, and Lloyd H.
- Smith, Jr., Editors; W.B. Saunders Co., 1988. Pp. 2284.
-
- HYPOXIA-SENSITIVE HYPEREXCITABILITY OF THE INTRAMUSCULAR NERVE AXONS IN
- ISAACS' SYNDROME. K. Oda, et al.; Ann Neurol (February 1989 issue 25 (2)).
- Pp. 140-145.
-
- ISAACS' SYNDROME. T.J. Brown; Arch Phys Med Rehabil (Jan 1984 issue 65
- (1)). Pp. 27-29.
-
- ISAACS' SYNDROME WITH MUSCLE HYPERTROPHY REVERSED BY PHENYTOIN THERAPY.
- J. Zisfein, et al.; Arch Neurol (April 1983 issue 40 (4)). Pp. 241-242.
-
-