Chiari Malformation: Causes, Symptoms, and Treatment
Medically reviewed by Sumiran Racherla, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Chiari Malformation?
A neurologist (a doctor who treats brain and nerve problems) usually diagnoses Chiari malformation, and a neurosurgeon (a doctor who does brain and spine surgery) treats it when surgery is needed. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is Chiari malformation?
Chiari malformation is a problem with the brain at the place where the skull meets the spine. The cerebellum (the part of the brain that controls balance) pushes down into the spinal canal (the space inside the spine). This can block the flow of cerebrospinal fluid (the clear liquid that cushions the brain and spinal cord).
Many people have no symptoms at all. Some are found by chance on a brain scan done for another reason.
Symptoms
Symptoms vary widely. The most common one is a headache near the base of the skull that gets worse with coughing, sneezing, or straining. Other symptoms include:
- Neck and shoulder pain.
- Dizziness and balance problems.
- Numbness, or tingling or burning in the fingers, toes, or lips.
- Trouble swallowing or speaking.
- Blurred or double vision, and ringing in the ears (tinnitus).
- Muscle weakness.
- Sleep apnea (pauses in breathing during sleep).
Some people also get a syrinx (a fluid-filled cyst inside the spinal cord). It can cause muscle weakness, numbness, and a curve in the spine (scoliosis).
Causes and who gets it
Most Chiari malformations happen before birth, while the brain and skull are developing. The exact cause is not known. In many people, the space at the back of the skull (the posterior fossa) is too small.
In extremely rare cases, a Chiari malformation develops later in life. It can happen when something takes up space in the skull, like a tumor, or when too much cerebrospinal fluid drains away. Sometimes more than one person in a family has it. This suggests that genes play a role in some cases. Slightly fewer than 1 in 1,000 people have a Chiari malformation.
How doctors diagnose it
Doctors start with a physical exam and a neurological exam (checks of balance, touch, reflexes, and movement). The main test is an MRI (magnetic resonance imaging), which uses magnets and radio waves to make pictures of the brain and spinal cord.
A diagnosis usually means the cerebellar tonsils (the lower parts of the cerebellum) hang below the foramen magnum (the opening at the base of the skull). Doctors often use 5 millimeters (about one-fifth of an inch) as the cutoff, but this number is debated. How far the tonsils hang down does not always match how bad the symptoms are.
A special MRI called cine MRI can show how cerebrospinal fluid flows. A CT scan (a detailed x-ray test) can show bone problems at the base of the skull.
Treatment
People with no symptoms usually do not need treatment. Doctors monitor them with checkups and imaging tests. For mild symptoms, pain medicines, massage, or cutting back on heavy lifting and straining may help.
Surgery is the main treatment when the malformation causes symptoms. Doctors may also recommend surgery when a syrinx is present. The most common surgery is posterior fossa decompression. The surgeon removes a small piece of bone from the back of the skull to make more room. Sometimes the surgeon also opens the dura (the covering of the brain and spinal cord) and sews in a patch to make more space.
Surgery can keep symptoms from getting worse. One study found that more than 80 percent of adults reported significant improvement in symptoms after surgery. However, some people still have pain or weakness afterward, and nerve damage that has already happened usually cannot be reversed. Surgery can also cause a cerebrospinal fluid leak or an infection. A syrinx usually improves after surgery. People with hydrocephalus (fluid buildup in the brain) may be treated with a shunt (a tube that drains extra fluid).
When to see a doctor
See a doctor if you have headaches near the base of the skull that get worse when you cough or sneeze, or if you notice tingling in your fingers, muscle weakness, or balance problems. In many babies who develop symptoms from Chiari malformation type 2, the symptoms start and get worse fast, and this needs urgent or emergency care. If anyone has trouble breathing, faints, or has sudden weakness or trouble speaking, call 911.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. For Chiari malformation, this doctor can do an evaluation, check on your symptoms over time, and refer you to a neurologist or neurosurgeon when needed.
Common questions
What are the first signs of Chiari malformation?
The most common symptom is a headache near the base of the skull that gets worse with coughing, sneezing, or straining. Neck pain, dizziness, and balance problems can also happen.
Is Chiari malformation inherited?
Sometimes. Reports of more than one affected person in a family suggest that genes play a role in some cases, but the exact cause is not known.
Does everyone with Chiari malformation need surgery?
No. People with no symptoms are usually just monitored. Surgery is the main treatment when the malformation causes symptoms.
What is a syrinx?
A syrinx is a fluid-filled cavity, or cyst, inside the spinal cord. Doctors also call it syringomyelia. Chiari malformation type 1 is the most common cause of syringomyelia.
Sources
- National Organization for Rare Disorders (NORD) - Chiari Malformations
- National Institute of Neurological Disorders and Stroke - Chiari Malformation
- American Association of Neurological Surgeons - Chiari Malformation
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
