A Comprehensive Guideto Understanding theChiari I Malformation
andSyringomyelia
Providing Research, Educationand Support for Syringomyelia
and Chiari Malformation
www.ASAP.org
Y O U R R E F E R E N C E B O O K L E T
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TABLE OF CONTENTS:
Chiari malformation ............................................2
Syringomyelia .....................................................7
Special considerationsfor children with CM and/or SM .......................13
Related disorders ..............................................16
Chiari malformation (CM)and syringomyelia (SM) at a glance ..................18
About ASAP ......................................................20
ChiariMalformation
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The Chiari malformation is an abnormalityin the lower part of the brain called thecerebellum. There are several differentforms. The most common type is theChiari I malformation (CM) which thisarticle addresses. Less commonly, it maybe known as Arnold-Chiari malformation,tonsillar herniation or tonsillar ectopia.Most cases of Chiari are congenital,meaning they are present from birth.
To help explain this condition, a quicklesson in brain anatomy is helpful.
In normal anatomy, the cerebellar tonsilsare located just above the line called theforamen magnum. But in an individualwith Chiari, the tonsils hang below theline (herniate) into the spinal canal. Thedegree to which the tonsils extend canvary tremendously.
Normal brain and spinal cord
An individual with the Chiarimalformation and a syrinx
What is the Chiari malformation?
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What are the symptoms?
The most common symptom of Chiarimalformation is a headache, which begins atthe back of the head (neck) and radiatesupward. The pain is often made worse or canbe brought on by coughing, sneezing orstraining. These activities are known as valsalvamaneuvers. A valsalva maneuver compressesthe blood flow in the chest, which in turn causesincreased pressure in the head. This can bringon severe symptoms in an individual with Chiari.
Visual problems such as nystagmus (involuntaryeye movements), double or blurred vision mayoccur. Balance difficulties, vertigo and dizzinessalso may be present. Some people may havecranial nerve compression. This can result inapnea (lapse in breathing), gagging, swallowingdifficulties, facial numbness or syncope(temporary loss of consciousness).
Patients may have muscle weakness, particularlyin the upper extremities, coordinationproblems, or gait abnormalities. Imaging of thespine may reveal a fluid collection insideof the spinal cord, known as a syrinx. Someindividuals may have hydrocephalus, a buildupof fluid in the ventricles of the brain.
Very young children often show a specific groupof symptoms: failure to thrive, repeatedincidents of aspiration pneumonia or adiagnosis of gastrointestinal reflux, difficultyswallowing, sleep apnea, developmental delaysand/or scoliosis.
It is possible to have a Chiari malformation andhave no symptoms. In fact, Chiari malformationshave been noted incidentally on MRIs taken fordifferent reasons. Researchers are looking forclues to help them better understand why somepeople have symptoms and others do not.
Researchers have found that the degree ofherniation does not always correspond with theseverity of symptoms. Some mild herniationsproduce large syrinxes or severe symptoms, whilelarge herniations may cause no symptoms at all.
What is the treatment?
The first step after diagnosis is to consultwith a neurosurgeon who has experiencetreating and managing this disorder. Beaware that you may need to travel andyou may wish to consult with more thanone specialist.
If symptoms are mild and not progressing,your doctor may recommend conservativemanagement. Supportive care such asheadache and pain management, physicaltherapy or a reduction in activities canhelp manage symptoms.
An operation may be recommended. Thisis referred to as a posterior fossadecompression. The surgeon makes moreroom in the back of the head by removingsmall pieces of the skull bones. Thisreduces compression of the brain stemand allows the tonsils to move back intotheir natural position. The specific surgicaltechniques will vary among surgeons; noconsensus yet exists on the best variationon this surgical procedure.
An average hospital stay ranges from 3 to5 days. The first night after surgery isusually spent in the intensive care unit.The typical patient is able to return to fullactivities within 4 to 6 weeks of surgery.Depending upon your individual situation,some restrictions on activities could benecessary. Physical therapy may berecommended to help regain functionand strengthen neck muscles.
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What is the prognosis?
The prognosis depends on the patient'soverall health prior to surgery and thepresence of other conditions. While noteveryone's symptoms will completely goaway, most patients will noticeimprovement. In some cases, additionalsurgical procedures could be necessary.
When surgery is not recommended,treatment plans are typically guided byregular neurological exams along with MRIscans. Symptoms could progress, stay thesame, or improve over time.
Is Chiari hereditary?
Researchers investigated the geneticimplications of the Chiari malformation withor without syringomyelia. A geneticprevalence has been identified in somefamilies. Researchers continue to search forthe gene(s) that are responsible forproducing the Chiari malformation.
MRI scanning is recommended for familymembers who have signs or symptoms ofthe disorder.
Syringomyelia
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What is a syrinx?What is syringomyelia?
The brain and spinal cord are surrounded bycerebrospinal fluid (CSF). This fluid helpstransport nutrients, eliminates waste products,and provides a cushion for the brain and spinalcord from trauma.
When the normal flow of spinal fluid isdisrupted or blocked, it can be forced insidethe spinal cord. The way in which this occurs isnot completely understood. As spinal fluid isforced into the spinal cord a fluid-filled cavity iscreated. This is known as a syrinx. It is alsosometimes called hydromyelia. Syrinxes aremost commonly found in the cervical spinalcord but can also be found in the thoracicand/or lumbar regions.
Over time, the syrinx can elongate or widen.This damages the spinal cord and can result inserious and/or disabling symptoms. Thecondition of having a syrinx is known assyringomyelia (SM).
Note the dark areaof the spinal cord.That is the syrinx.
What causes syringomyelia?
The most common cause of SM is acongenital condition known as the Chiarimalformation (CM). The cerebellar tonsilslie abnormally low in the spinal canal,causing a blockage in the normal flow ofspinal fluid.
The second major cause of a syrinx isspinal cord injury. Bony abnormalities,hemorrhaging and scarring that resultfrom severe spinal damage oftencontribute to a syrinx development. Thismay occur years after the original injury.The syrinx can cause further muscleweakness or additional loss of functionwhich can be devastating to a spinal cordinjury patient.
SM can be caused by any condition thatblocks the normal flow of spinal fluid.Other causes include spinal or braintumors, arachnoid cysts, meningitis (whichcan cause arachnoiditis or scarring), atethered spinal cord, a condition in whichthe cord lies lower than normal,prohibiting it from moving freely.
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What are the symptoms?
Symptoms develop slowly over time, but cancome on suddenly after a fall or minor trauma.Sensation may be affected first. Loss ofsensitivity to hot and cold, numbness andtingling can occur. Bowel and bladder functionmay be affected. Motor symptoms includemuscle weakness, spasticity, paralysis and, insevere cases, quadriplegia.
Scoliosis is a common finding in individualswith SM, and it may be the only symptom inchildren. Often people with scoliosis undergospinal MR imaging because of an atypicalleft-sided thoracic curve.
Many individuals suffer from chronic pain andsome will develop neuropathic painsyndromes. This type of pain is difficult totreat. A large percentage of people haveheadaches which can be severe.
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What is the treatment?
The first step after diagnosis is to consult witha neurosurgeon who has significantexperience in treating and managing thisdisorder. Be aware that you may need to traveland you may wish to consult with more thanone specialist.
Treatment is aimed at restoring the normalflow of spinal fluid. In persons with Chiari andSM, a procedure known as a posterior fossadecompression may be recommended. Thisprocedure allows the cerebellar tonsils to moveinto a normal position, restoring the normalflow. After this procedure the syrinx will oftenreduce or resolve on its own. This can takemonths and may never completely collapse thesyrinx. Some patients may require repeatsurgeries. The most important consideration indeciding to undergo surgery is the severity ofsymptoms and overall quality of life issues.
In syrinxes associated with other causes, thesurgical treatment is also aimed at restoringnormal physiology and flow of spinal fluid.This might involve a bony spinaldecompression, removing a tumor or scartissue. In cases of tethered spinal cord, asurgical procedure is used to release thetension on the cord, allowing it to return to itsnormal position.
The most desirable outcome of any surgery forSM is to stop progression. Surgery mayimprove symptoms and reduce the size of thesyrinx. However, damage to the spinal cord isnot always reversible and neurological painand dysfunction may not completely go away.SM associated with CM usually has a bettersurgical outcome than other causes of SM.Children with Chiari and syringomyelia, inparticular, tend to have the best outcomes.That is why early diagnosis is essential.
Syrinx drainage used to be the primarytreatment of SM. In a shunting procedure, atiny tube is inserted into the syrinx which
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drains to a cavity outside of the spinalcolumn. A subarachnoid shunt drains thesyrinx fluid into the space surrounding thespinal cord.
Shunting procedures are associated with agreater risk. Shunts frequently becomeclosed or dislodged, and repeated surgerymay be necessary. In addition thisprocedure does not address theunderlying reason the syrinx developed.
Not all patients will require surgery. Ifsymptoms are mild and not progressing,your doctor may recommend conservativemanagement. Non-surgical interventionssuch as headache management, painmedication, physical therapy, occupationaltherapy and changes in lifestyle can helpmanage symptoms.
Is the condition progressive?
The natural history of untreated SM ispoorly understood. Some patients willcontinue to have a progression ofsymptoms, and the syrinx cavity willcontinue to enlarge. Others will remainstable for years or a lifetime. Regularneurological exams and periodic MRIscans help monitor your condition.
Specialconsiderations for
children withCM and/or SM
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Special considerations for childrenwith syringomyelia and/or Chiari
When a child is diagnosed it affects the wholefamily, not just the child. Parents may feeloverwhelmed, powerless, and afraid. But thereis a lot you can do. Taking control and playingan active role in your child’s healthcare isessential. By researching the condition, you willbe better prepared to advocate for your child.
Children and adolescents should be treated bya pediatric neurosurgeon. Generally pediatricneurosurgeons are affiliated with children'shospitals. Regular monitoring is critical whendealing with children who may not be able tocommunicate symptoms as well as adults can.
A pediatric neurosurgeon will perform adetailed exam and review of films. Additionaltesting may be necessary. Other specialists mayneed to be consulted, i.e., orthopedist, neuro-ophthalmologist, urologist, neurologist.
Children who have a functional impairment willqualify for accommodations to help themsucceed in school. An individual educationalplan (IEP) can be developed with the help ofyour school.
ActivitiesWhether or not your child has had surgery, thereare no general rules pertaining to permittedactivities. However, this is an important topic todiscuss with the pediatric neurosurgeon whocares for your child. Some children who havehad extensive surgical procedures or who havebony abnormalities may be prohibited fromcertain activities.
We know that symptoms can be brought on bya fall or minor trauma. Be sure your child wearsprotective head gear when participating inactivities such as riding a bike or a scooter.
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The asymptomatic childDue to the widespread availability of MRItechnology, more children are being scannednow than ever before, and in some cases, aChiari malformation is discovered despitehaving no symptoms.
Learning that your child has Chiari and/or asyrinx when you had no idea that anythingcould be wrong is a frustrating and worrisomesituation for parents. On the one hand, parentsdo not want their child to undergo surgery, butthey fear without surgery the child could sufferfrom permanent damage in the future. Thenatural history of Chiari with or withoutsyringomyelia is not fully understood. Somepeople may go their entire lives and neverdevelop any symptoms. Therefore, surgery israrely recommended for the asymptomatic child.Nevertheless, a pediatric neurosurgeon shouldbe consulted in all cases.
Talk to your childChildren may feel isolated and different fromtheir peers when they are dealing with adisorder such as CM or SM. Letting children talkabout their feelings will help them cope. Theymay have unfounded fears and worries such asdying or becoming paralyzed.
It is important to explain the condition andnecessary procedures in a way your child canunderstand. Consider discussing the details ofsurgery with the surgeon while the child is not inthe room. However, encourage the child to voicequestions to the neurosurgeon. Most children'shospitals have child life specialists who can helpwith the process of preparing for surgery.
Related disorders
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Related disordersThere are several conditions that are oftenassociated with Chiari and syringomyelia.They include:
Arachnoiditis—inflammation of the arachnoidmembrane in the spinal canal. It can be causedby trauma, spinal surgery, hemorrhage, orinfection. It can result in severe pain. There is nocure or treatment when it is widespread.
Basilar invagination—a condition in which aportion of the C2 to vertebra (called theodontoid), compresses the brain stem. It isdiagnosed with x-rays and MRIs.
Chiari II malformation—usually found in childrenwith spina bifida or myelomeningocele. Notonly is part of cerebellum unusually low andlying below the bottom of the skull, but thebrain stem can be malformed in several ways.
Chiari III and IV malformation—Types III and IVrepresent gross herniations of the cerebellumand are very rare. They represent totalherniation of the brainstem and cerebellum intothe spinal canal, and are often associated with acervical encephalocele.
Hydrocephalus—a buildup of fluid in theventricles of the brain. This condition is usuallytreated by a placing a ventricle-peritoneal shuntto drain the fluid into the peritoneal (liningsurrounding contents of the belly) cavity. Thecondition can be diagnosed by CT scan.
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Intracranial hypertension (pseudotumorcerebri)—an abnormally high cerebrospinalfluid (CSF) pressure in the brain. Symptomsinclude headache, nausea, vomiting andvisual problems. Optic nerve swelling can bediagnosed by a dilated eye exam. Pressure ismeasured by spinal tap, but more extensivemonitoring may be necessary in a hospitalsetting. In these cases, a neurosurgeon willdrill a small hole in the skull and insert a fiberoptic wire into the skull to measure the CSFpressure for an extended period of time. Thisgives the surgeon a more accurate clinicalpicture. The wire is then removed, andgenerally only one staple or a single stitch isneeded to close the wound. Treatmentsinclude medical therapies to reduce CSF fluidproduction or a shunt to remove CSF.
Neuropathic pain syndrome—pain caused bydamage to the central nervous system. This ischaracterized by burning pain and abnormalsensations. It can be associated withallodynia, which is a painful sensationoccurring after light touch. Neuropathic painis difficult to treat but responds best to thedrugs that specifically treat neuropathic pain.
Spina bifida—a birth defect in which thespinal cord fails to close during fetaldevelopment. There are many different formsof spina bifida ranging from benign (spinabifida occulta) to severe (myelomenigocele).Most patients with myelomeningocele willhave the Chiari II malformation.
Syringobulbia—the formation of a syrinx inthe brain stem.
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Chiari malformation (CM) andsyringomyelia (SM) at a glance
> Estimates are that syringomyelia affects over250,000 Americans. No one knows how manypeople have Chiari, but the number is likelyto be at least double that of SM.
> CM and SM are diagnosed by MRI.
> Most cases of Chiari are detected in earlyadulthood, but as awareness and technologyincrease, children are diagnosed morefrequently.
> Chiari is thought to be congenital but canbe acquired due to conditions such ashydrocephalus, intracranial hypertensionand certain shunt types such as thelumboperitoneal shunt.
> Chiari is the most common cause ofsyringomyelia, but not every person withChiari will develop a syrinx.
> Idiopathic syrinxes—those with no knowncause—are uncommon. A thorough searchfor the cause should be undertaken.
> Chiari I malformation and syringomyelia arenot considered fatal conditions.
> Not all patients need surgery. The decision tooperate requires careful consultation betweenthe patient and surgeon and is usually basedon symptoms.
> A syrinx can resolve on its own without anymedical therapy, although this is very rare.
> Tonsillar herniation can increase over time orafter trauma. Alternately, the degree ofherniation can recede. This is more commonin young children whose growing skulls maypermit more room for the tonsils.
> Many individuals suffer from chronic pain andheadaches, but not all.
> Surgical treatment for SM is aimed at restoringthe normal flow of spinal fluid.
> Although surgery may not result in thecomplete disappearance of a syrinx, asuccessful surgery will, in most cases, allowthe syrinx to reduce and stop progressing.
AT A GLANCE
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About ASAP
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About ASAP
The American Syringomyelia Alliance Project, Inc.(ASAP) is a not-for-profit, 501(c)(3), member-supported organization chartered in May 1988.ASAP is the result of the commitment anddetermination of its two founding members,Barbara and Don White, whose journey withsyringomyelia (SM) and Chiari malformation (CM)began in1983.
Barbara was experiencing numbness in her lefthand, headaches and other unexplainedsymptoms. After three weeks of hospitalizationand testing, she was finally diagnosed withsyringomyelia. Barbara later learned she alsohad Chiari.
Their efforts to learn about these conditionsproved to them that very little was known, andfew physicians were even aware of the limitedinformation that was available. The frustrationsthey faced years ago mirror those of many withSM and CM even today. While we now know thatmore than 70% of SM cases are caused by Chiarimalformation, much is still unknown. ASAP’s goalis to provide people with SM/CM the supportand direction that was unavailable to Barbara whenshe began her journey. Unfortunately, she did notlive to see the blossoming of her organization.Barbara died from complications of syringomyeliaand Chiari in 1991. However, ASAP continues tomake strides toward the goals she set.
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ASAP provides:• Connections, a bi-monthly newsletter• An annual conference• Funding for research• Teleconferences and webinars• Networking and peer support• An informational web site• Email announcements• Educational materials• Awareness merchandise
ASAP ’ s Miss ionHelp Us
To improve thelives of persons affected
by syringomyelia,Chiari malformation andrelated disorders while
we find the cure
Copyright 2009
This brochure has been prepared bythe American Syringomyelia
Alliance Project, Inc.
SPECIAL THANKS TO OUR EDITORS:
John Heiss, MDNational Institutes of Health
Bethesda, Maryland
John Oró, MDNeurosurgery Center of Colorado
Chiari Treatment CenterAurora, Colorado
©2009 American Syringomyelia Alliance Project. Inc. All rights reserved.
CONTACT US:
American Syringomyelia Alliance Project, Inc.PO Box 1586
Longview, TX 75606-15861-800-ASAP-282or 903-236-7079www.ASAP.org
