| Print Date: | May 19, 2013, 3:03 pm |
| Title | Arnold-Chiari Malformations |
| Text | Chiari Malformations (CM) are divided into 4 subtypes.
• CM - 1 is diagnosed by appropriate symptoms and low lying cerebellar tonsils (cerebellar tonsillar ectopia - tonsils > 5mm below foramen magnum). The phsyiology is not related to the degree of hernation, but rather to the CSF flow around the tonsils. Symptoms include: » Decreased sensation/numbness in extremities » Upper extremity pain, weakness » Headache » Tinnitus » Decreased facial sensation (spinal portion of CNN V) » Gait disorder, bowel/bladder Sx, Nystagmus NOTE: Patients may be symptomatic with only 3mm of herniation; and, asymptomatic with up to 10 mm. Syringohydromyelia is associated in 20-25%. • CM - 2 Is like CM-1, but includes a spinal dysraphism (myelomeningocele). This is the "Arnold-Chiari" malformation. The posterior fossa may be small, and both the cerebellum and 4th ventricle are herniated through the Foramen Magnum, usually with "kinking" of the medulla and/or cervical cord (up to 70%). These patients usually have a complex malformation including hydrocephalus, a "beaked" midbrain, callosal anomalies (up to 90%, such as agenesis of the rostrum and or splenium. • CM - 3 Chiari III malformation is like a CM - 2, but includes a cervical/occipital encephalocele. • CM - 4 Chiari IV is controversial and not accepted by all authors. It is a small or underdeveloped cerebellum. ================================ http://www.pressenter.com/~wacma/milhorat.htm http://cpmcnet.columbia.edu/dept/nsg/PNS/ChiariMalformation.html http://rad.usuhs.mil/rad/home/spine/davospine.html |
| References: | |
| Contributor | James George Smirniotopoulos, M.D. (Uniformed Services University) |
| Peer Reviewer | James G. Smirniotopoulos, M.D. (Uniformed Services University) |
| Record Number | : 436 |
| Created | 1998-01-28 00:00:00-05 |
| Modified | 2007-03-16 15:14:27-04 |
| Category: | Congenital, malformation |
| Location: | Brain and Neuro |
| Sublocation: | Posterior Fossa |
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