What is Chiari Malformation?

Chiari malformation (CM) is a congenital (present at birth) structural abnormality of the brain, where a portion of the cerebellum (the part of the brain responsible for balance and coordination) called the cerebellar tonsils extend into the upper spinal canal through the opening at the base of the skull. This can put pressure on the brainstem and obstruct the normal flow of cerebrospinal fluid (CSF).

There are several types of Chiari malformation, but the most common ones are:

  1. Chiari Malformation Type I (CM-I): In this type, the cerebellar tonsils extend into the upper spinal canal, but the brainstem is not displaced. CM-I is the most prevalent form and is usually detected during adolescence or adulthood.
  2. Chiari Malformation Type II (CM-II): In CM-II, more brain tissue, including the cerebellar vermis and brainstem, herniates through the opening at the base of the skull. This type is often associated with a myelomeningocele, a type of spina bifida, and is usually diagnosed shortly after birth or during pregnancy.


In some cases, Chiari malformation may not cause any symptoms and is only discovered incidentally during imaging tests for other conditions. However, when symptoms do occur, they can vary widely based on the type of Chiari malformation and the degree of herniation. Common symptoms may include:

  1. Headaches: Often described as a pressure-like or throbbing headache, typically worsened by coughing, straining, or sudden movements.
  2. Neck Pain: Persistent pain or discomfort in the neck, especially in the back of the head.
  3. Balance and Coordination Problems: Issues with balance, coordination, and fine motor skills.
  4. Weakness: Weakness or numbness in the arms and legs.
  5. Dizziness: Episodes of dizziness or vertigo.
  6. Vision Problems: Blurred or double vision, sensitivity to light, or other visual disturbances.
  7. Swallowing and Speech Difficulties: Trouble with swallowing or speech.
  8. Sleep Apnea: Difficulty breathing during sleep.


Treatment for Chiari malformation depends on the severity of the symptoms and the type of malformation. In cases where the condition is asymptomatic or causes only mild symptoms, no treatment may be necessary, but regular monitoring is recommended.

If symptoms are more severe or progressive, treatment options may include:

  1. Pain Management: Over-the-counter or prescription medications to relieve headache and neck pain.
  2. Surgery: In cases where there is significant compression of the brainstem or worsening neurological symptoms, surgery may be recommended. The most common surgical procedure is a posterior fossa decompression, which aims to create more space and relieve pressure on the brain and spinal cord.
  3. Shunting: For cases where there is associated hydrocephalus (accumulation of excess CSF in the brain), a shunt may be placed to divert the CSF to another part of the body.

It’s essential for individuals with Chiari malformation to work closely with a healthcare team, including neurologists and neurosurgeons, to determine the best treatment approach based on their specific case and symptoms. Early diagnosis and appropriate management can help improve the quality of life for those affected by Chiari malformation.