Arnold-Chiari malformation
Arnold-Chiari malformation is a malformation of the brain. It consists of a downward displacement of the cerebellar tonsils and the medulla through the foramen magnum, sometimes causing hydrocephalus as a result of obstruction of CSF outflow.
http://en.wikipedia.org/wiki/File:Chiari.jpg
A T2-weighted sagittal MRI scan, from a patient with Chiari-like symptomatology, demonstrating tonsillar herniation less than 3 mm (MRI scan photo)
Terminology
Some sources use "Chiari malformation" to describe four specific grades of the condition, reserving the term "Arnold-Chiari" for type II only. Other sources use "Arnold-Chiari" for all four types. This article uses the latter convention.
One advantage of using "Arnold-Chiari" is that the term "Chiari's syndrome" can refer to Budd-Chiari syndrome, a hepatic condition also named for Hans Chiari.
Diagnosis
The average age at diagnosis is about 27 and it is more common in women, but is also found in men.
Some characteristics are visible prenatally.
Some of these malformations come about as a result of accidents or traumas, as well as being from congenital defects.
Incidence
The incidence of Arnold-Chiari Malformation (Chiari I malformation) defined as tonsilar herniations of 3 to 5 mm or greater is approximately 1 in 1,200. The incidence of symptomatic Chiari is less but unknown.
A prevalence of approximately 1 in 1000 has been described.
History and classification
The Austrian pathologist Hans Chiari in the late 1800s described seemingly related anomalies of the hindbrain, the so called Chiari malformations I, II and III. Later, other investigators added a fourth (Chiari IV) malformation. The scale of severity is rated I - IV, with IV being the most severe. Types III and IV are very rare.
The most common form of Arnold-Chiari Malformation is Type I, which is generally asymptomatic during childhood, but often manifests with headaches and cerebellar symptoms.
Type II is usually accompanied by a myelomeningocele leading to partial or complete paralysis below the spinal defect. Abnormal development of the cerebellar vermis and medulla occur, and they both descend into the foramen magnum. Hydrocephalus is also nearly always present.
Type III causes severe neurological defects. It is associated with an encephalocele.
Type IV involves a failure of brain development.
Other conditions sometimes associated with Chiari Malformation include hydrocephalus, syringomyelia, spinal curvature, and connective tissue disorders such as Ehlers-Danlos syndrome and Marfan Syndrome.
Symptoms
The brainstem, cranial nerves, and the lower portion of the cerebellum may be stretched or compressed. Therefore, any of the functions controlled by these areas may be affected. The blockage of Cerebro-Spinal Fluid (CSF) flow may also cause a syrinx to form, eventually leading to syringomyelia. Chiari is often associated with major headaches, sometimes mistaken for migraines. Chiari headaches usually include intense pressure in the back of the head, aggravated by laughing, coughing, sneezing or straining. Chiari also includes extreme muscle soreness, facial pain, hearing problems, fainting spells, dizziness, balance problems, numbness, tingling, poor motor skills, speech problems, vision problems, difficulty walking correctly, and so many more, including low energy levels. It also can cause insomnia cycles of sleep deprivation followed by but not always the inabilities to remain awake cycling between them. The inability to sleep also carries symptoms of extreme lethargy or extreme aggravation, the desire to stay secluded, the inability of interact properly in social situations or relationships, the inability to function in any given situation, short attention span, memory problems, learning problems, becoming overwhelmed by even the smallest tasks, and not being able to care. 15% of patients with adult Chiari malfomation are asymptomatic.
Treatment
Once symptomatic onset occurs, a common treatment is decompression surgery, in which a neurosurgeon usually removes the first and part of the second and sometimes third cervical vertebrae and part of the occipital bone of the skull to allow the flow of spinal fluid and may be accompanied by a shunt. This treatment is well recognized and accepted with many studies published (involving a total of hundreds of patients) in well-respected peer-reviewed medical journals showing that about 80% of patients obtain improvement.Some authors advocate performing a transoral clivus-odontoid resection in cases with ventral brain-stem compression, as they feel these patients may potentially deteriorate with posterior fossa decompression alone.
A small number of neurological surgeons believe that detethering the spinal cord as an alternate approach relieves the compression of the brain against the skull opening (foramen magnum), obviating the need for decompression surgery and associated trauma. However, this approach is significantly less documented in the medical literature, with reports on only a handful of patients. It should be noted that the alternative spinal surgery is also not without risk.
History
An Austrian pathologist, Hans Chiari, first described these hindbrain malformations in the 1890s. A colleague of Professor Chiari, Dr. Julius Arnold, later contributed to the definition of the condition, and students of Dr. Arnold (Schwalbe and Gredig) suggested the term "Arnold-Chiari malformation" to henceforth refer to the condition.
Some sources credit the characterization of the condition to Cleland or Cruveilhier.
More On Symptoms
Doctors categorize Chiari malformation into four types, depending on the anatomy of the brain tissue that is displaced into the spinal canal, and whether developmental abnormalities of the brain or spine are present.
Many people with Chiari malformation have no signs or symptoms and don't need treatment. Their condition is detected only when tests are performed for unrelated disorders. However, depending on the type and severity, Chiari malformation can cause a number of problems.
The more common types of Chiari malformation are:
Type I (adult)
Type II (pediatric)
In Chiari malformation type I, signs and symptoms usually appear during late childhood or adulthood. Chiari II malformation is usually noted by ultrasound during pregnancy or at birth or early infancy. Although these types are less serious than the more rare pediatric forms, types III and IV, signs and symptoms still can be life disrupting.
Chiari malformation type I
Headaches, often severe, are the classic symptom of Chiari malformation. They're typically precipitated with sudden coughing, sneezing or straining. People with Chiari malformation type I also can experience:
Neck pain (running down the shoulders at times)
Unsteady gait (problems with balance)
Poor hand coordination (fine motor skills)
Numbness and tingling of the hands and feet
Dizziness
Difficulty swallowing (sometimes accompanied by gagging, choking and vomiting)
Vision problems (blurred or double vision)
Slurred speech
Less often, people with Chiari malformation may experience:
Ringing or buzzing in the ears (tinnitus)
Poor bladder control
Chest pain, in a band-like pattern around the chest
Curvature of the spine (scoliosis) related to spinal cord impairment
Abnormal breathing — specifically, sleep apnea characterized by periods of breathing cessation during sleep
Chiari malformation type II
In Chiari malformation type II, a greater amount of tissue protrudes into the spinal canal compared with type I. The signs and symptoms can include those related to a form of spina bifida, called myelomeningocele, that always accompanies Chiari II malformation. In myelomeningocele, the backbone and the spinal canal have not closed properly before birth.
Chiari malformation type III
In one of the most severe types of the condition, Chiari malformation type III, a portion of the lower back part of the brain (cerebellum) or the brainstem extends through an abnormal opening in the back of the skull. This form of Chiari malformation is obvious at birth or by intrauterine ultrasound.
Chiari malformation type IV
In people with the even more severe Chiari malformation type IV, the brain itself has never developed normally. This form is also obvious at birth or by intrauterine ultrasound.
When to see a doctor
If you or your children have any of the signs and symptoms that may be associated with Chiari malformation, see your doctor for an evaluation.
Because many symptoms of Chiari malformation can also be associated with other disorders, a thorough medical evaluation is important. Head pain, for example, can be caused by migraines, sinus disease or a brain tumor, as well as Chiari malformation. Other signs and symptoms overlap with other conditions, such as multiple sclerosis.
References
^ "urmc.rochester.edu".
^ Rosenbaum, RB; DP Ciaverella (2004). Neurology in Clinical Practice. Butterworth Heinemann. pp. 2192–2193. ISBN 0-7506-7469-5.
^ "Dorlands Medical Dictionary:Chiari malformation".
^ "Case Based Pediatrics Chapter".
^ "2008 ICD-9-CM Diagnosis 453.0 - Budd-Chiari Syndrome".
^ "Fetal MRI: Arnold-Chiari Malformation".
^ a b "Arnold Chiari Malformation".
^ "Neuroradiology - Chiari malformation (I-IV)".
^ MeSH Arnold-Chiari+Malformation
^ "Chiari Malformations - Department of Neurological Surgery".
^ "Neuropathology For Medical Students".
^ Milhorat TH, Bolognese PA, Nishikawa M, McDonnell NB, Francomano CA (December 2007). "Syndrome of occipitoatlantoaxial hypermobility, cranial settling, and chiari malformation type I in patients with hereditary disorders of connective tissue". Journal of neurosurgery. Spine 7 (6): 601–9. doi:10.3171/SPI-07/12/601. PMID 18074684.
^ Guo F, Wang M, Long J, et al (2007). "Surgical management of Chiari malformation: analysis of 128 cases". Pediatr Neurosurg 43 (5): 375–81. doi:10.1159/000106386. PMID 17786002.
^ Chiari, H. Uber Veranderungen des Kleinhirns infolge von Hydrocephalie des Grosshirns. Dtsch. Med. Wochenschr. 17: 1172-1175, 1891.
^ Arnold, J. Myelocyste, Transposition von Gewebskeimen und Sympodie. Beitr. Path. Anat. 16: 1-28, 1894.
^ Ashwal, Stephen (1990). The Founders of child neurology. San Francisco: Norman Pub. in association with the Child Neurology Society. pp. 195. ISBN 0-930405-26-9.
^ Arnold-Chiari malformation at Who Named It
^ Bejjani GK (2001). "Definition of the adult Chiari malformation: a brief historical overview". Neurosurg Focus 11 (1): E1. doi:10.3171/foc.2001.11.1.2. PMID 16724811.
^ Susman J, Jones C, Wheatley D (March 1989). "Arnold-Chiari malformation: a diagnostic challenge". Am Fam Physician 39 (3): 207–11. PMID 2923030.
^ Cleland (April 1883). "Contribution to the Study of Spina Bifida, Encephalocele, and Anencephalus". J Anat Physiol 17 (Pt 3): 257–92. PMID 17231474.
^ Pearce JM (January 2000). "Arnold chiari, or "Cruveilhier cleland Chiari" malformation". J. Neurol. Neurosurg. Psychiatr. 68 (1): 13. PMID 10601393.
See Also
Brown-Sequard Syndrome (Syringomyelia Section)
External links
Conquer Chiari
World Arnold Chiari Malformation Association
American Syringomyelia Alliance Project
The Ann Conroy Trust (ACT)
An insightful Huffington Post blog from a father whose son suffered from Chiari Malformation and the emotional roller coaster it created.
v • d • e
Congenital malformations and deformations of nervous system (Q00-Q07, 740-742)
Brain
Anencephaly (Acephaly, Acrania, Iniencephaly) - Encephalocele - Microcephaly - Congenital hydrocephalus (Dandy-Walker syndrome)
other reduction deformities (Holoprosencephaly, Lissencephaly, Pachygyria, Hydranencephaly)
Septo-optic dysplasia - Megalencephaly
Congenital cerebral cysts (Porencephaly, Schizencephaly) - Congenital brain tumors
Polymicrogyria (Bilateral frontoparietal polymicrogyria)
Brain stem
Arnold-Chiari malformation
Spinal cord
Spina bifida - Currarino syndrome - Sacrococcygeal teratoma - Diastematomyelia - Syringomyelia
see also non-congenital CNS and PNS (G, 320-359)
Category: Neurological disorders
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CONQUER CHIARI
Millions are suffering everyday from this condition.
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Chiari Malformation (Arnold-Chiari) is a serious neurological disorder where the bottom part of the brain, the cerebellum, descends out of the skull and crowds the spinal cord, putting pressure on both the brain and spine and causing many symptoms.
Quick Facts About Chiari Malformation:
Affects more than 300,000 people in the US; 30% of children born with spina bifida are also born with a Chiari Malformation.
Causes a wide ranging, diverse set of symptoms. Research has shown that 95% of patients experience at least 5 symptoms.
Diagnosed using combination of MRI, neurological exam, physician’s judgment, and other tests; patients often go 5 or more years before being properly diagnosed.
A study of over 300 Chiari Malformation patients found that 57% had at one time been told by a doctor they were suffering from a mental or emotional problem.
Many patients undergo serious brain surgery in an attempt to stop symptoms from progressing.
Research has shown that surgery can improve symptoms for about 80% of patients, but fails about 20% of the time.
Chiari can place a tremendous physical, mental, emotional, and economic strain on patients and their families.