Chiari malformations

When brain tissue gets pushed where it doesn’t belong, our experienced neurosurgery team knows what to do. Some children only need careful observation, while others may benefit from new and safer surgical repairs. Either way, we can help your child overcome a Chiari malformation.

Read about Donovan, who has benefited from a mix of watchful waiting and surgery while receiving care from Advocate Children's Hospital for a Chiari malformation.

What is a Chiari malformation?

With a Chiari malformation, brain tissue sticks into a skull opening, typically the one reserved for the top of the spinal cord. Most often, the tissue comes from the cerebellum, the part of the brain that controls balance. Sometimes it also contains some of the brain stem, the structure that manages communications and runs essential tasks such as breathing.

There are three main kinds of Chiari malformations:

• Type I::These malformations are the most common and involve the lower part of the cerebellum. Type 1 malformations may not cause symptoms, or the symptoms may not get noticed until someone is a teenager or an adult.
• Type II: Tissue from both the cerebellum and brain stem push down into the opening with this form, also called an Arnold-Chiari malformation. While symptoms are typically more severe, surgery can help children go on to lead typical lives. Children often need an operation when they’re young.
• Type III: With these malformations, an unusual opening forms in the back of the skull. Parts of the cerebellum and brain stem stick out, sometimes also joined by membranes, or coverings, for the brain and spine. These malformations are very rare and come with further complications, including seizures and changes to how the brain and body develop.

What causes Chiari malformations?

Brain tissue gets pushed out of place with a Chiari malformation because the skull is too small or has an unusual shape. These characteristics typically start forming in the womb for reasons doctors don’t yet fully understand. Genetic changes in the baby and diet during pregnancy may both play a role.

In rare cases, a Type 1 malformation develops after birth, from spinal fluid loss through injury, infection or exposure to harmful substances.

Chiari malformation symptoms

The type of Chiari malformation affects whether a child experiences symptoms, as well as which ones and their severity. Without treatment, symptoms can also change over time as fluid builds up or brain tissue and nerves receive more pressure.

For newborns, a malformation may cause the infant to fuss more and affect their ability to develop motor control or thrive. In other children, signs of a Chiari malformation may include:

• Dizziness or problems with balance or hearing
• Difficulty breathing, including during sleep, eating, swallowing or speaking
• Double or blurred vision or rapid, unexplained eye movement
• Headaches, particularly after coughing, sneezing or otherwise straining
• Head and neck pain
• Sensitivity to light
• Stiffness or spasticity
• Weakness or loss or sensation in the upper body

Other neurological conditions connected to Chiari malformations

Children with a Chiari malformation may also develop excess fluid in the brain (hydrocephalus). They can have problems with their backbone, too, including:

• Curved spine (scoliosis)
• Cyst in the spinal cord (syringomyelia)
• Incomplete closure of spinal covering (spina bifida)
• Restricted spinal cord (tethered spinal cord)

Chiari malformation diagnosis

Type 1 Chiari malformations often get discovered accidentally when doctors order scans for another health problem. Some malformations also get noticed during routine ultrasounds given during pregnancies. Otherwise, parents or pediatricians observe symptoms or complications.

Regardless of what prompts families to see us, our doctors give a full neurological exam. They check on cognition, memory, balance, reflexes, motor control and sense of touch. Learn more about our neurology program, and what to expect from an exam.

To confirm a diagnosis, we typically order one or more scans:

• Magnetic resonance imaging (MRI): A combination of magnets, radio waves and computers creates images of soft tissues. These scans help us see the shape of the brain and are the most common imaging for diagnosing a Chiari malformation.
• X-rays: Small doses of targeted radiation produce images of bones and some tissues. X-rays can provide information on the shape of the skull.
• Computer tomography (CT): These machines use the same radiation as X-rays but take multiple, detailed scans, which computers can convert into 3D images.

Chiari malformation treatment

Children and teens with Type 1 Chiari malformations often only need monitoring. We give them MRIs on a set schedule to check their brain health. We can also prescribe medications for symptoms that are uncomfortable but otherwise harmless such as headaches.

For severe symptoms and other malformations, we typically recommend surgery to make room for the cerebellum and relieve spinal cord pressure. We do so by trimming the bottom of the skull and possibly removing the bone that caps the spinal canal. Surgeons in the past also opened the dura, which covers the brain and spine. But we take a newer approach that tries to avoid that step, since doing so keeps your child safer.

Other Chiari malformation treatment

In addition to decompression surgery, children may need a shunt (special tubing) placed in their brain to drain extra fluid. And some babies need spinal correction for a form of severe spina bifida called a myelomeningocele while still in the womb.