A Chiari malformation is a congenital (present at birth) defect in the area of the back of the head where the brain and spinal cord connect. The condition is also called Arnold Chiari malformation.

Four Types of Chiari Malformations

Type I - commonly goes unnoticed until problems arise in the adolescent or adult years of life. In this condition, the base of the skull and the upper spinal area are not formed properly.

Type II - this is the most common type of Chiari malformation. In this condition, part of the back of the brain shifts downward through the bottom of the skull area.

Type II Chiari malformations are typically seen in infants who are born with spina bifida, a neurological condition that causes a portion of the spinal cord and the surrounding structures to develop outside, instead of inside, the body. Type II Chiari malformations can also be associated with a condition known as hydrocephalus. Hydrocephalus is a condition in which there is an overproduction or lack of absorption of the cerebral spinal fluid (CSF) that is found inside the ventricles (fluid-filled areas) inside of the brain. The increased fluid causes the pressure inside of the head to increase and the skull bones to expand to a larger than normal appearance.

Type III - the back of the brain protrudes out of an opening in the back of the skull area.

Type IV - the back of the brain fails to develop normally.

Chiari Malformation Causes

Although the exact cause of Chiari malformation is unknown, it is thought that a problem during fetal development may cause the abnormal brain formation.

Theories suggest that the following may predispose the fetus to problems that affect the normal development of the head during pregnancy:

  • exposure to hazardous chemicals/substances
  • lack of proper vitamins and nutrients in the diet
  • infection
  • prescription or illegal drug use and alcohol consumption

Chiari Malformation Symptoms

The following are the most common Chiari malformation symptoms. However, each child may experience different symptoms. In infants and older children born with this Chiari malformation, symptoms may include:

  • rapid back and forth eye movement
  • developmental delays
  • poor feeding and swallowing
  • vomiting
  • stiffness or pain in the neck or back of the head area
  • weak cry
  • breathing problems, sleep apnea, snoring
  • headaches
  • decreased strength in the arms or hands

Chiari malformation symptoms may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.