Chiari Malformation

Chiari malformations are structural defects that cause symptoms ranging from headaches and muscle weakness to developmental delays and breathing problems. Typically, they occur in the area where the brain and spinal cord meet. In most cases, parts of the brain push down into the spinal canal and cause pressure in the brain and on the spinal cord. This often blocks the flow of cerebrospinal fluid (CSF), which can cause fluid-filled cysts on the spinal cord and hydrocephalus (a buildup of fluid in the brain). There are four types of Chiari malformations. Types III and IV are rarely seen.

Type I is the most common and can go undiagnosed until symptoms develop during childhood, adolescence, or even into adulthood. This type can cause fluid-filled cysts (syringomyelia) on the spinal cord. Scoliosis (spine curvature) often is associated with type I.

Type II typically affects children born with spina bifida, specifically infants with myelomeningoceles -- spinal cord tissue that protrudes through an opening in the spine.

Type III is a rare and very serious form of Chiari malformation. Some parts of the brain may stick out, or herniate, through an abnormal opening in the back of the skull. 

Type IV is very rare. In this type, part of the brain is underdeveloped or missing.

Duke Children’s pediatric neurosurgeons combine clinical evaluation with advanced testing to fully understand your child’s condition and recommend the right level of care for type I and type II Chiari malformations. 

Type I Chiari Malformations
For type I Chiari malformations, we conduct a thorough medical history and physical examination, including a review of family history to look for a possible genetic cause. We also perform a detailed neurological assessment of your child. A sudden headache when coughing, sneezing, or laughing -- anything that causes pressure in the head -- is one of the most common symptoms.

Type II Chiari Malformations
For type II malformations occurring with spina bifida, we collaborate with your child’s neurologist and otolaryngologist (to assess for evidence of brainstem dysfunction) for diagnosis and treatment.

Imaging Tests
We may recommend imaging tests, such as MRI or CT scans, to confirm the diagnosis. A special type of MRI -- a cine MRI scan or CSF flow study -- will show the flow of cerebrospinal fluid and help determine whether it’s building up in the brain or spine.

Monitoring
If your child’s symptoms are minor, we may recommend monitoring the Chiari malformation with periodic imaging as your child grows. In younger children, a Chiari malformation may actually improve on its own, and surgery may not be needed.