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Anonymous Use-Author-Address-Header at [127.1]
Mon Dec 8 12:48:41 EST 1997


      World Arnold-Chiari Brain Malformation (ACM) Association (WACMA)
                      http://wacma-chiari.home.ml.org
                    31 Newtown Woods Road, Newtown Square
                           Philadelphia, PA 19073
                          UNITED STATES OF AMERICA

    Free, not-for-profit support group for patients/parents and source of
    updated information for Doctors (mainly Neurologists and Neurosurgeons)
           and other Medical Professionals (RNs, PTs, GPs, etc)

                                President:
                   Ms. Darlene Long-Thompson, RN, MHSc.

                              Co-President:
                           Mr. Bernard H. Meyer

       Free membership and free support/information E-Mailing Lists.
                     http://wacma-chiari.home.ml.org
                  Information available English, Spanish.



                  Chiari Malformations and Syringomyelia
                  ______________________________________

   - Factsheet

   The CSIND, in collaboration with Dr. Thomas Milhorat and colleagues of
   SUNY-Brooklyn, the American Syringomyelia Alliance Project, and the
   Canadian Syringomyelia Network is investigating the hereditary basis
   of Chiari type I malformations with or without syringomyelia.

   * What are Chiari malformations?

   Chiari malformations occur in the region where the brain and spinal
   cord join. The lowerportions of the brain (cerebellar and/or
   brainstem) are located lower than normal, penetrating out of the skull
   or protruding into the spinal canal.

   Chiari malformations were first described in the 1890's by Professor
   Chiari, a German pathologist. He assigned a grade to the malformations
   beginning with Type I, the mildest form, classification today. Chiari
   malformations are also known by the followi ng medical terms:
   herniation of the cerebellar tonsils, cerebellar ectopia, hindbrain
   herniation, and Arnold-Chiari malformations, with Arnold-Chiari
   malformations being specific to type II malformations. Scientists and
   physicians further define Chiari malformations by the exact millimeter
   of brain stem that extends into the neck.

   Chiari type I malformations are a result of the smallest degree of
   herniation and are not associated with spina bifida. Chiari type II
   malformations are almost exclusively associated with a type of spina
   bifida known as a myelomeningocele, an opening of the spine and spinal
   cord on the lower back. Chiari type III and IV malformations are very
   rare.

   * What other disorders can occur with Chiari malformations?

   Chiari malformations can occur with other conditions. Some are:

     * hydrocephalus (excessive fluid in the brain)
     * spina bifida (opening of the spine usually associated with an
       abnormality of the spinal cord)
     * syringomyelia (excessive fluid in the spinal cord, leading to a
       cavity detectable by MRI).
     * other conditions, including some inherited conditions like
       achondroplasia (a type of dwarfism), Hajdu-Cheney syndrome,
       Albright hereditary osteodystrophy (pseudohypoparathyroidism),
       or other rarer syndromes.


   * What causes Chiari malformations?

   Scientists do not know the cause of Chiari malformations. Still, there
   are several hypotheses. One theory suggests that the base of the skull
   is too small in some individuals and this forces the cerebellar region
   lower than it should be. Another theory suggests that the growth of
   the cerebellar region is thrown off and overgrowth occurs resulting in
   the cerebellar region of the brain being compressed lower than it
   should be. Research studies are ongoing to learn how Chiari
   malformations occur.

   * How is syringomyelia associated with Chiari malformations?

   Syringomyelia (sear-IN-go-my-EEL-ya) is a disorder where abnormal
   collection of fluid occurs the spine. This collection of fluid, composed
   of cerebral spinal fluid (CSF), is referred to as a "syrinx" or a
   "cyst." Syringomyelia can be occur as a res ult of a car accident or
   other trauma. Syringomyelia can also occur with Chiari malformations or
   spinal tumors. The symptoms and signs of this disorder are often vague
   and may include weakness, fatigue, stiffness, or loss of ability to feel
   hot or cold .

   Syringomyelia can be diagnosed with a magnetic resonance imaging (MRI)
   study.

   * Are Chiari malformations inherited?

   There are several families reported in medical literature in which
   more than one family member has a Chiari malformation. However, no
   research study has ever been done to prove or disprove whether Chiari
   malformations are inherited. If more than one person in your family
   has a Chiari malformation or a spinal cord problem, please contact
   CSIND. CSIND's toll free telephone number (800)283-4316.
   Participation in the study involves answering questions about
   family and medical history, allowing CSIND rese archers to review
   medical records to confirm the diagnosis of Chiari malformation, and
   in some instances providing a blood sample to the CSIND.


   * Resources for Families

   American Syringomyelia Alliance Project (ASAP)

   National network founded in 1988. Offers support, networking &
   information for individuals with syringomyelia.

   P.O. Box 1586
   Longview, TX 75606-1586
   tel (903) 236-7079
   fax (903) 757-7456


   World Arnold-Chiari Brain Malformation Association (WACMA)

   Free, not-for-profit support group for Arnold-Chiari Malformation and
   Syringomyelia patients/parents and source of updated information for
   Doctors (mainly Neurologists and Neurosurgeons) and other Medical
   Professionals (RNs, PTs, GPs, etc.) - international network Founded
   February 1996.

   http://wacma-chiari.home.ml.org
   31 Newtown Woods Road, Newtown Square
   Philadelphia, PA 19073
   Contact person: Mr. Bernard Meyer, Philadelphia, (610)353-4737


   Arnold-Chiari Family Network

   International network founded in 1985. Informal network of families
   affected by symptomatic Arnold-Chiari malformation with spina bifida.
   Provides phone support, newsletter & networking of multiplex families.

   c/o Maureen & Kevin Walsh
   67 Spring Street
   Weymouth, MA 02188
   (617) 337-2368


   Canadian Syringomyelia Network

   69 Penny Crescent Markham,
   Ontario L3P5X7
   (905) 471-8278


   National Organization for Rare Disorders (NORD)

   P.O. Box 8923
   New Farfield, Connecticut 06812-8923
   (203) 746-6518
   (800) 999-6673


   National Institute of Health NIH-NINDS

   Federal Bldg, Room 814
   7550 Wisconsin Avenue
   Bethesda, MD 20892
   Ph: (301) 496-5821
   Fax: (301) 402-0302


   Center for the Study of Inherited and Neurological Disorders (CSIND)

   Duke University Medical Center
   P.O. Box 2900
   Durham, N.C. 27710
   (800) 283-4316 toll free
   Outside the United States please call collect (919) 684-6515

   1. http://www.mc.duke.edu/depts/genetics/csind/brochure.html
   5. http://www.mc.duke.edu/
   6. http://www.mc.duke.edu/depts/genetics/csind/index.html





1. Introduction: Arnold-Chiari Malformations (ACM) and Syringomyelia (SM)

Current nomenclature recognizes three different types of Chiari Malformations
consisting of various degrees of herniation of the cerebellar tonsils and
medulla below the foramen magnum. Type I malformation is characterized
primarily by caudal displacement of the cerebellar tonsils below the
foramen magnum with absent of minimal descent of the medulla. The fourth
ventricle is always in a normal position. Syringomyelia (or Hydromyelia)
often accompanies Chiari-1 Malformations: it has been noted in 30-75% of
patients.

Type II malformation is a more extensive anomaly with elongation and caudal
displacement of the cerebellar tonsils, inferior vermis, fourth ventricle,
choroid plexus and medulla. These structures descend into the cervical
spinal canal, often extending to the level of the fourth or fifth cervical
vertebra. It is almost invariably a component of myelodysplasia and the
associated hydrocephalus. Type III (ACM-3) malformation is a form of high
cervical meningocele with displacement of the cerebellum and lower brainstem
into the dysplastic sac. Over the years, the terms syringomyelia and
hydromyelia have been applied to a variety of diseases that have as the end
result an intramedullary cyst associated with progressive neurological
deficits.

2. Major Neurosurgery

There is general agreement that patients presenting with moderate or severe
neurological deficits fare much worse suggesting that early intervention may
improve prognosis. Neonatal Chiari II malformations continue to have
significant morbidity and mortality. Most series describe between 23 and 50%
long term mortality. Tracheostomy (creation of a new airway outlet through
the neck) and gastrostomy (creation of a new food inlet through the
abdominal wall) or nasogastric (a tube through the nose, down the throat to
the stomach) feedings are often required for months after decompression.
Intervention prior to the onset of bilaterall vocal cord paralysis is
associated with early improvement and eventual complete recovery.

Operative mortality for Chiari 1, Chiari II in older children and
hydromyelia ranges from 0 to 15% with recent series reporting near zero
mortality. There were no deaths among 70 consecutive patients treated by
the author over the past 9 years. The predominant cause of death in the
literature was respiratory failure followed by postoperative hematoma,
acute hydrocephalus and medullary (see Anatomy - S4.2) infarction from
damage to the posterior inferior cerebellar artery (P.I.C.A.). Morbidity
includes aseptic meningitis, bradycardia, and respiratory dysfunction with
apnea. When myelotomy has been performed, proprioceptive loss or
dysesthesias may rarely occur. Whether or not morbidity is increased with
more extensive procedures remains unclear.

Note: paragraphs (c)Rick Abbott, M.D. Pediatric Neurosurgeon -
"Your child and Neurosurgery: Arnold-Chiari Malformations", 1996,
practice: New York Beth Israel Medical Center, http://www.bethisraelny.org



Please visit (free, not-for-profit organizations...):

http://wacma-chiari.home.ml.org
http://www.chiari.com
http://www.syringo.org

Thank you for your interest.
John A. MacDonald, Ph.D.






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