A Chiari malformation is a problem in which a part of the brain at the rear of the skull bulges through a normal opening (foramen magnum) in the skull where it joins the spinal canal. This puts pressure on parts of the brain and spinal cord, and can cause mild to severe symptoms. In most cases, the problem is present at birth (congenital).
There are 3 main types of Chiari malformations. Type 1 is the most common. This article is about type 2. In this type, 2 parts of the brain (cerebellum and brainstem) bulge through the foramen magnum.
This problem can happen in newborns who have spina bifida or spinal myelomeningoceles. A myelomeningocele is when part of the spinal cord and backbone (spine) grow outside the body instead of inside.
What causes a Chiari II malformation?
Chiari II malformations are present at birth (congenital). Doctors do not know what causes this malformation. They think that something happens to the fetus while it is growing that causes the brain to form abnormally. Chiari malformations may be caused when a pregnant woman is exposed to harmful substances that affect her developing baby. Or they may be a genetic problem that tends to run in families.
What are the symptoms of a Chiari II malformation?
Signs and symptoms of Chiari II malformations depend on the age of your child. Newborns may have:
- Spinal myelomeningocele or spina bifida
- Noisy breathing
- Trouble swallowing
- Breathing food or fluid into the lungs (aspiration)
- Short periods of not breathing (apnea)
- Weakness in the arms
Older infants and children may have:
- Hydrocephalus that gets worse over time
- Abnormal shape of the spine (scoliosis)
- Eyesight problems
- Hearing loss
- Trouble using their hands to pick up and use small objects
Children may also have extra fluid in the brain stem or spinal cord (syrinx). This may cause pain in the arms or legs, or make it hard for your child to walk.
How is a Chiari II malformation diagnosed?
The diagnosis is often done at birth. This is because Chiari II malformation usually occurs with other birth defects. The doctor may also be able to find the defect during pregnancy with fetal ultrasound.
The doctor uses imaging tests to find Chiari malformations. Your child may need:
- MRI. This test uses a combination of large magnets, radio waves, and a computer to create detailed pictures of organs and structures within the body. MRI is the best test for diagnosing Chiari malformations. If an MRI cannot be done, the doctor may order a high-resolution CT scan.
- CT scan. This test uses X-rays and a computer to make horizontal (axial) pictures of the body. A CT scan shows bones, muscles, fat, and organs.
How are Chiari II malformations treated?
Your child may need to see several kinds of health care providers for treatment. These include experts in brain and spinal cord problems (neurologists and neurosurgeons).
Your child’s health care provider will figure out the best treatment for your child based on:
- How old your child is
- His or her overall health and health history
- How sick he or she is
- How well your child can handle specific medicines, procedures, or therapies
- How long the condition is expected to last
- Your opinion or preference
Treatment for a Chiari II malformation may include surgery to:
- Ease pressure on the brain and let spinal fluid flow (decompression).
- Close a myelomeningocele. This may be right after birth.
- Put a flexible tube (shunt) in the brain. This is to drain extra fluid (hydrocephalus).
- Put a shunt in the spinal cord to drain fluid from a syrinx.
Your child may also need:
- Treatment for bowel and bladder problems
- Special feedings
- Breathing support
What are the complications of a Chiari II malformation?
Complications of Chiari malformations include:
- Syrinx develops or gets worse
- Permanent damage to muscles or nerves
- Too little oxygen gets to your child’s lungs (respiratory failure)
A Chiari malformation can also be fatal.
How are Chiari II malformations managed?
Health care providers cannot often tell what will happen in a child with a Chiari malformation. Your child may stay about the same. Or your child may have nerve or brain problems that get worse. Your child’s health care provider will watch your child closely. Your child will need physical exams and imaging tests done often.
Your child may need ongoing care:
- Speech therapy for swallowing problems
- Nutrition therapy
- Physical, occupational, and rehabilitation therapy
When should I call my child's health care provider?
Call your child’s health care provider if you see any changes in your child. Be sure to call if you notice problems with:
- Walking or moving
Also call your child’s provider if your child has a severe headache or neck pain.
Key points about Chiari II malformations
- Chiari II malformation a problem in the way the brain and skull are formed. It is 1 of 3 main types of this malformation.
- Most Chiari malformations are present at birth.
- A newborn with a spinal myelomeningocele almost always has a Chiari II malformation. The child usually also has hydrocephalus.
- Infants with Chiari II malformations usually have breathing or feeding problems.
- Treatment for a Chiari II malformation may include surgery to ease pressure on the brain. A child with a myelomeningocele may need surgery to drain extra fluid in hydrocephalus.