Chiari malformations are structural defects that affect tissue in the brainstem, cerebellum (the area of the brain at the back of the skull), and spinal cord. They can cause symptoms ranging from headaches and neck pain to issues with sleep and swallowing.
Types of Chiari Malformations
Chiari malformations can be categorized into different types, with Chiari malformation type I being the most common.
Type I symptoms can develop during childhood, adolescence, or even into adulthood. With Chiari malformation type I, the brain bulges through an opening at the base of the skull, putting pressure on the brain and spinal cord. This can block the normal flow of cerebrospinal fluid (CSF), causing hydrocephalus (a buildup of fluid in the brain) or a syrinx (a fluid-filled cyst within the spinal cord). A syrinx can lead to numbness, tingling, weakness, back or extremity pain, scoliosis, or changes in bowel or bladder function.
Type II typically affects children born with spina bifida, specifically infants with a myelomeningocele -- 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.