1. History 14 yr old female with history of hydrocephalus with shunt placement, lower limb paralysis, and Arnold-Chiari malformation.14 yr old female with history of hydrocephalus with shunt placement, lower limb paralysis, and Arnold-Chiari malformation.

2. Arnold Chiari Malformations Type I: Most common form, generally asymptomatic during childhood, but often manifests with headaches, blurred vision, and cerebellar symptoms.Type I: Most common form, generally asymptomatic during childhood, but often manifests with headaches, blurred vision, 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 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. Rare.Type III causes severe neurological defects. It is associated with an encephalocele. Rare. Type IV involves a failure of brain development. Rare.Type IV involves a failure of brain development. Rare.

3. History 14 yr old female with history of hydrocephalus with shunt placement, lower limb paralysis, and Arnold-Chiari malformation.14 yr old female with history of hydrocephalus with shunt placement, lower limb paralysis, and Arnold-Chiari malformation.

5. Radiologic Findings Budd Chiari IIBudd Chiari II A small posterior fossa, mild tectal beaking and cerebellar herniation through an enlarged foramen magnum. Hydrocephalus.A small posterior fossa, mild tectal beaking and cerebellar herniation through an enlarged foramen magnum. Hydrocephalus.

6. History 34 yr old female with unbearable neck pain.34 yr old female with unbearable neck pain.

8. Radiologic Findings Budd Chiari IBudd Chiari I Cerebellar and Medulla herniation through the foramen magnumCerebellar and Medulla herniation through the foramen magnum

9. History 5 month old male with hypotonia, failure to thrive, history of ventriculomegaly on fetal ultrasound.5 month old male with hypotonia, failure to thrive, history of ventriculomegaly on fetal ultrasound.

11. Radiologic Findings Budd Chiari IVBudd Chiari IV Cerebellar and Brainstem hypoplasiaCerebellar and Brainstem hypoplasia

12. Take Home Points Four types of Arnold-Chiari MalformationFour types of Arnold-Chiari Malformation Type I most common. Usually presents in adulthood – headaches, blurred vision, neck pain. Treatable with surgery.Type I most common. Usually presents in adulthood – headaches, blurred vision, neck pain. Treatable with surgery. Type II-IV manifest in childhood and are associated with neurological deficits.Type II-IV manifest in childhood and are associated with neurological deficits.