Types | Symptoms | Causes and Risk Factors | Diagnosis | Treatment | Support

Chiari malformations refer to several abnormalities affecting the portion of the brain where it connects to the spinal cord. The symptoms usually associated with a Chiari malformation are similar to many other conditions. For example, symptoms of multiple sclerosis (MS) and Chiari malformations are often mistaken for each other. Because both conditions can cause neurological symptoms, some neurologists may stop looking for the cause of symptoms when they find a Chiari malformation. What’s more, Chiari malformation is relatively easy to diagnose based on imaging like an MRI. As a result, people who have both conditions sometimes find that their MS is initially missed because doctors believe their symptoms are caused by the malformation.

Here is what you need to know about the relationship between MS and Chiari malformation, including types, symptoms, causes, diagnosis, and treatment options.

Types of Chiari Malformations

There are various types of Chiari malformations (types are sometimes noted with Roman numerals, as types I through IV):

• Type 1 — The most common form, which happens when the lower part of the cerebellum pushes into the foramen magnum.
• Type 2 — Also called Arnold-Chiari malformation. The cerebellum and brain stem tissue push into the foramen magnum.
• Type 3 — The most serious form is when some of the cerebellum and the brain stem stick out through an abnormal opening in the back of the skull.
• Type 4 — Involves an underdeveloped cerebellum, which is called cerebellar hypoplasia. This type is very rare.

Symptoms of MS and Chiari Malformation

A Chiari malformation is a term used to describe when tissue from the brain — specifically, the brain stem and the part of the brain called the cerebellum — moves into the spinal canal. In someone with a Chiari malformation, cerebrospinal fluid may not be able to circulate properly. Part of the skull has an unusual shape or is small, forcing brain tissue downward instead of staying in the skull.

Headaches

The symptoms of Chiari malformation can vary widely, and people often have different symptoms. One of the most common symptoms is a headache that begins near the base of the skull, but you may also experience neck pain and shoulder pain. Headaches are often severe and may cause sharp, stabbing pains.

Vision and Balance Problems

People with Chiari malformations are also likely to have eye problems. They may have double vision (diplopia), or their vision may be blurred. They may also experience dizziness, hearing problems, ringing in the ears (tinnitus), problems swallowing, muscle weakness, problems with balance and coordination, tingling or burning, fainting, sleep apnea, and difficulty sleeping.

Many of these symptoms overlap with those of MS. Although people with MS alone are unlikely to experience the type of headaches characteristic of Chiari malformation, the other above symptoms could also be symptoms of MS.

Causes and Risk Factors of MS and Chiari Malformation

You can be diagnosed with both MS and Chiari malformation, but the causes of these conditions are completely unrelated.

No one knows exactly what causes a Chiari malformation. Researchers do know that the shape of the skull seems to force brain tissue into the spinal canal. There are possible hereditary connections, but the specifics of these are currently unknown.

Genetics is considered to be one factor of MS, but it is also believed to be triggered by certain infections and environmental factors that lead to the development of an autoimmune disorder.

Diagnosing MS and Chiari Malformation

Determining whether a person should be diagnosed with MS, Chiari malformation, or both can be a challenge. The process of narrowing down potential conditions to arrive at the correct diagnosis is called differential diagnosis.

The first thing doctors will consider is the symptoms the person is experiencing. Although symptoms may not always be the same, the severe, persistent headaches that many people with Chiari malformations have are not usually experienced by those with MS. If the person has MS, it is not usually the cause of that kind of headache.

Therefore, people with headaches at the base of the skull may be examined for Chiari malformation, whether or not they also have a diagnosis of MS.

Syringomyelia is the development of a fluid-filled cyst (syrinx) in your spinal cord. Although syringomyelia may be associated with MS, it is more closely associated with Chiari malformation. People diagnosed with MS who have (or develop) syringomyelia should also be evaluated for Chiari malformation. Syringomyelia is detected through MRI.

The best diagnostic test for making a differential diagnosis between the two conditions (or determining whether a person should be diagnosed with both) is with MRI. The two conditions appear very differently on these images.

Chiari malformations will appear as abnormalities in the shape or structure of the brain, skull, and related areas. MS will show up as lesions (areas of demyelination) in the central nervous system.

Several MyMSTeam members have expressed frustration with this diagnostic process. One wrote, “I am in the process of a diagnosis, and my MRI just showed Chiari malformation as well as lesions, which seems to be complicating everything.”

Another member shared similar sentiments, asking, “Has anyone else been diagnosed with a Chiari malformation along with MS? It took forever to get my MS diagnosis because my MRIs showed a Chiari malformation, which can produce some of the same symptoms as MS. However, a Chiari malformation doesn’t cause lesions, and I have several.”

Treatments for MS and Chiari Malformation

MS and Chiari malformation are treated differently.

There is no single treatment for Chiari malformation. Minor cases may be treated with pain medication or massage and monitored for complications. More serious cases may require neurosurgery. Based on the specifics of the individual’s skull shape and other factors, different decompression surgeries or procedures may be recommended. Many times, treatment for Chiari malformation involves a team of doctors, often including neurologists, neurosurgeons, and eye specialists.

There are many treatments available for slowing down disease progression in MS. Some disease-modifying therapies are injected under the skin at home. Others are taken by mouth or administered by infusion in a clinic. Flare-ups may be treated with corticosteroids or plasma exchange. Physical therapy and occupational therapy may help people cope with symptoms and improve their quality of life.

If you have been diagnosed with MS and Chiari malformation, it’s important to treat both conditions. The good news is that if you have successful Chiari surgery, you should experience a significant reduction in your symptoms. MS, on the other hand, does not have a cure and requires continuous monitoring and treatment.

Make sure that your health care and neurology teams know about all of your diagnoses or potential diagnoses. This information will allow them to choose the right treatments and evaluations for you. With time and trial and error, as well as the right medical advice, you should be able to find ways to treat both conditions that work for you.

Find Your Team

MyMSTeam is the online social network for people with multiple sclerosis and their loved ones. On MyMSTeam, more than 185,000 members come together to ask questions, give advice, and share their stories with others who understand life with MS.

Your team will know what you’re going through and will be ready to help you improve your quality of life and sense of well-being while living with MS.

Have you been diagnosed with Chiari malformation in addition to MS? Share your story or thoughts in the comments below or by posting on MyMSTeam.