Arnold Chiari Malformation: Difference between revisions
Wendy Walker (talk | contribs) No edit summary |
Wendy Walker (talk | contribs) No edit summary |
||
| Line 34: | Line 34: | ||
The key tests for diagnosis of Arnold Chiari Malformation are [[MRI Scans|MRI]] and CT scans<ref>Curnes JT, Oakes WJ, Boyko OB. MR imaging of hindbrain deformity in Chiari II patients with and without symptoms of brainstem compression. AJNR Am J Neuroradiol. 10 (2): 293-302</ref>.<br> | The key tests for diagnosis of Arnold Chiari Malformation are [[MRI Scans|MRI]] and CT scans<ref>Curnes JT, Oakes WJ, Boyko OB. MR imaging of hindbrain deformity in Chiari II patients with and without symptoms of brainstem compression. AJNR Am J Neuroradiol. 10 (2): 293-302</ref>.<br> | ||
Antenatal ultrasound imaging shows an indentation of the frontal bone with an abnormally shaped cerebellum<ref>El gammal T, Mark EK, Brooks BS. MR imaging of Chiari II malformation. AJR Am J Roentgenol. 1988;150 (1): 163-70</ref>. | Antenatal ultrasound imaging shows an indentation of the frontal bone with an abnormally shaped cerebellum<ref>El gammal T, Mark EK, Brooks BS. MR imaging of Chiari II malformation. AJR Am J Roentgenol. 1988;150 (1): 163-70</ref>.<br> | ||
== Differential Diagnosis<br> == | == Differential Diagnosis<br> == | ||
| Line 42: | Line 40: | ||
The main differential diagnosis is the type of Chiari malformation.<br> | The main differential diagnosis is the type of Chiari malformation.<br> | ||
Chiari 1 malformation does not have a myelomeningocoele. | Chiari 1 malformation does not have a myelomeningocoele.<br> | ||
== Epidemiology == | |||
It used to be said that Chiari malformations are rare, but with routine use of MR imaging Chiari malformation is discovered with increasing frequency.<span> </span> | |||
Chiari II is found in all children with myelomeningocele, although less than one-third develop symptoms referable to this malformation<ref>Dias M. Myelomeningocoele. In: Choux M, Di Rocco C, Hockley A, Walker M. Pediatric Neurosurgery. London: Churchill Livingston; 1999:33-61.</ref>.<br> | |||
== Resources <br> == | == Resources <br> == | ||
Revision as of 23:16, 22 September 2014
Original Editor - Wendy Walker
Lead Editors
Introduction[edit | edit source]
Arnold Chiari Malformation, AKA Chiari type II malformation, is one of a group of brain malformations affecting the cerebellum[1].
They are named after Hans Chiari, the pathologist who first described the whole group of malformations, and another pathologist, Julius Arnold[2].
It is almost always associated with myelomeningocele.
Clinically Relevant Anatomy
[edit | edit source]
Normally the cerebellum and parts of the brain stem sit in an indented space at the lower rear of the skull, above the foramen magnum (a funnel-like opening to the spinal canal). When part of the cerebellum is located below the foramen magnum, it is called a Chiari malformation.
In Arnold Chiari Malformation both cerebellar and brain stem tissue protrude into the foramen magnum. In addition, the cerebellar vermis (the nerve tissue that connects the two halves of the cerebellum) may be only partially complete or absent.
This condition has skull, dural, brain, spinal, and spinal cord manifestations, including downward displacement of the medulla, fourth ventricle, and cerebellum into the cervical spinal canal, as well as elongation of the pons and fourth ventricle, probably due to a relatively small posterior fossa[3].
The brainstem is elongated and displaced into the opening of the base of the skull and into the top of the spinal canal[4]. It is often kinked. The brainstem, cranial nerves and lower portion of the cerebellum may be stretched or compressed. This means that any of the functions controlled by these areas may be affected.
Clinical Presentation[edit | edit source]
Many people with Arnold Chiari malformation have no obvious symptoms.
In babies, the most common symptoms are a weak or absent cry, stridor (noisy breathing), arching of the neck, breathing problems, colour change, failure to thrive and feeding or swallowing difficulties.
The blockage of cerebrospinal fluid (CSF) flow may also cause a syrinx to form, eventually leading to syringomyelia. Central cord symptoms such as hand weakness, dissociated sensory loss, and, in severe cases, paralysis may occur.
Diagnostic Procedures[edit | edit source]
The key tests for diagnosis of Arnold Chiari Malformation are MRI and CT scans[5].
Antenatal ultrasound imaging shows an indentation of the frontal bone with an abnormally shaped cerebellum[6].
Differential Diagnosis
[edit | edit source]
The main differential diagnosis is the type of Chiari malformation.
Chiari 1 malformation does not have a myelomeningocoele.
Epidemiology[edit | edit source]
It used to be said that Chiari malformations are rare, but with routine use of MR imaging Chiari malformation is discovered with increasing frequency.
Chiari II is found in all children with myelomeningocele, although less than one-third develop symptoms referable to this malformation[7].
Resources
[edit | edit source]
add appropriate resources here
Recent Related Research (from Pubmed)[edit | edit source]
Extension:RSS -- Error: Not a valid URL: Feed goes here!!|charset=UTF-8|short|max=10
References[edit | edit source]
References will automatically be added here, see adding references tutorial.
- ↑ Koehler PJ. Chiari's description of cerebellar ectopy (1891). With a summary of Cleland's and Arnold's contributions and some early observations on neural-tube defects. J Neurosurg. Nov 1991;75(5):823-6
- ↑ Schijman (2004). "History, anatomic forms, and pathogenesis of Chiari malformations". Child's nervous system 20 (5): 323
- ↑ Truivit CL, Backovich A. Disorders of brain development. In: Atlas SW, ed. Magnetic Resonance Imaging of the Brain and Spine. 2nd ed. Philadelphia, Pa: Lippincott-Raven; 1996.
- ↑ Stevenson KL. Chiari Type II malformation: past, present, and future. Neurosurg Focus. Feb 15 2004;16(2):E5.
- ↑ Curnes JT, Oakes WJ, Boyko OB. MR imaging of hindbrain deformity in Chiari II patients with and without symptoms of brainstem compression. AJNR Am J Neuroradiol. 10 (2): 293-302
- ↑ El gammal T, Mark EK, Brooks BS. MR imaging of Chiari II malformation. AJR Am J Roentgenol. 1988;150 (1): 163-70
- ↑ Dias M. Myelomeningocoele. In: Choux M, Di Rocco C, Hockley A, Walker M. Pediatric Neurosurgery. London: Churchill Livingston; 1999:33-61.
