Chiari Malformation

Types of Chiari malformation

Chiari malformations are most often present at birth. However, in rare cases, the condition can develop later in life due to injury, disease or conditions that cause excess fluid buildup in the skull. These are known as secondary or acquired Chiari malformations.

No matter when a Chiari malformation develops, doctors classify it into one of four types based on which parts of the brain extend into the spinal canal and the severity of the condition. This classification helps guide treatment decisions.

Chiari malformation causes

A Chiari malformation happens when the lower part of the brain pushes down into the spinal canal, the space where your brain and spinal cord meet. This is caused by a structural issue in the brain and spinal cord, where the area that holds your cerebellum (the part of the brain that controls movement) is smaller than usual. This extra pressure causes the cerebellum to move to an unusual spot. This typically happens while babies are still developing in the womb.

The condition is often linked to a genetic change (mutation) inherited from your family, or it can happen randomly after conception. In very rare cases, a Chiari malformation can develop later in life, even if you weren't born with it. This can happen if there’s a change in the shape of your skull or spinal cord caused by:

• A brain tumor
• A cyst
• Blood buildup (hematoma)
• Fluid buildup in the brain (hydrocephalus)
• Increased pressure in the brain (intracranial hypertension or pseudotumor cerebri)

Sometimes, a Chiari malformation can also be seen alongside other health conditions like:

• Goldenhar syndrome
• Achondroplasia (a form of dwarfism)
• Connective tissue disorders like Ehlers-Danlos syndrome
• Spina bifida

Complications

In some people, a Chiari malformation may not cause any symptoms, and they may not need treatment. However, in others, the condition can worsen over time and lead to serious complications. These complications may include:

• Hydrocephalus: This occurs when too much fluid builds up in the brain, which can affect thinking and cause other issues. People with hydrocephalus may need a shunt, a flexible tube that helps drain the extra fluid to another part of the body.
• Spina bifida: This is a condition where the spinal cord or its protective covering doesn't fully develop. Part of the spinal cord may be exposed, leading to serious problems like paralysis. People with Chiari malformation Type II often have a type of spina bifida called myelomeningocele.
• Syringomyelia: Some people with Chiari malformation also develop syringomyelia, where a cyst or cavity (called a syrinx) forms in the spinal cord. As it grows, the syrinx can put pressure on the nerves, causing pain, weakness, and stiffness.
• Tethered cord syndrome: In this condition, the spinal cord becomes attached to the spine, causing it to stretch. This can lead to nerve and muscle damage, especially in the lower body.

How is Chiari malformation diagnosed?

To diagnose a Chiari malformation, your doctor will do a physical exam and check things like your memory, balance, coordination, reflexes and movement. They may also order imaging tests to confirm the diagnosis or to look for other conditions, such as fluid buildup in the brain (hydrocephalus) or bone abnormalities.

Chiari malformation treatment

Your doctor will develop a personalized treatment plan tailored to your specific needs, considering factors like the severity of your symptoms, how they affect your daily life and your personal goals. Not everyone with Chiari malformation needs treatment. If you don't have any symptoms, your doctor may recommend monitoring the condition with regular imaging tests. You and your doctor can always adjust your plan and start treatment if symptoms appear.

If your Chiari malformation causes symptoms, your doctor might suggest lifestyle changes, therapy or medications to help manage things like headaches. For more severe symptoms, surgery to create more space for the cerebellum or address related problems, like hydrocephalus, may be the most effective solution.

Frequently asked questions