Chiari Malformation

Overview

A Chiari malformation (say: kee-AR-ee) is a condition where the lower part of the brain sits lower than usual. The brain sits inside the skull, which has a small opening at the bottom where it joins the spinal canal. In a Chiari malformation, a bit of the brain's lower part (the cerebellum, the area that helps with balance and movement) pushes down through that opening. This can put pressure on the brain and spinal cord, and it can block the normal flow of fluid that surrounds the brain and spinal cord. Some people have no problems at all. Others get headaches, neck pain, balance issues or other symptoms. Many people only find out they have it after a scan done for another reason.

Type 1 is the most common form. Studies that look at brain scans suggest it may be seen in about 1 in 100 people, but many of those people never have symptoms or even know they have it. The other types are much rarer.

Anyone can have a Chiari malformation, because it is usually present from birth. Type 1 is often picked up in young adults, roughly between the teenage years and the 40s, and it seems to be slightly more common in women. Type 2 is usually found in babies who are also born with spina bifida (a condition where the spine does not form fully). Some people are only diagnosed later in life when they have a scan for something else.

Symptoms

Common symptoms

• Headache, often felt at the back of the head, that gets worse with coughing, sneezing, laughing, bending over or straining
• Neck and shoulder pain
• Dizziness or a feeling of unsteadiness
• Problems with balance or coordination
• Tingling, numbness or weakness in the arms, hands, legs or feet
• Blurred vision, double vision or sensitivity to light
• Ringing or buzzing in the ears
• Trouble swallowing, a feeling of food sticking, or choking easily
• Hoarse voice or slurred speech
• Feeling very tired, or trouble sleeping
• A heavy feeling in the arms and legs

Symptoms in children

• Feeding problems, poor weight gain or trouble sucking and swallowing
• Choking or gagging during feeds
• Vomiting and being very irritable or hard to settle
• A head that looks larger than expected, or a different head shape in babies
• Pauses in breathing while asleep (sleep apnoea, where breathing briefly stops during sleep)
• Falling behind on sitting, crawling or walking, or finding it hard to keep up with other children
• Frequent crying, especially when lying flat, or holding the head in an unusual position
• Sore neck or back, or a stiff neck

Symptoms in older adults

• Neck pain and stiffness that may be blamed on wear and tear in the spine
• Problems with balance or walking that could be mistaken for getting older
• Numbness or tingling in the hands and feet
• Headaches that are worse with coughing, sneezing or lifting
• Trouble swallowing or a feeling of food sticking in the throat
• Being very tired, or unsteady on the feet
• Often found by chance when a scan is done for another reason

Causes

Main causes

• It is usually present from birth (congenital). It happens while the baby is developing in the womb, when the space at the base of the skull ends up smaller than usual, so the lower brain is pushed down.
• In Type 1 the cause is not usually known. It is thought that genes and the shape of the skull both play a part.
• Type 2 is usually linked with spina bifida, where the spine and spinal cord do not form completely.
• Type 3 and Type 4 are rare and more serious forms, present from birth, where part of the brain or spinal cord pushes out through the skull or is not fully formed.
• In some people, other spinal cord problems such as a tethered cord (where the spinal cord is stuck at the bottom) are found alongside it.

Risk factors

• Having a close family member with a Chiari malformation or with spina bifida
• Being born with spina bifida or another condition that affects the spine and nervous system
• Being female, as Type 1 seems slightly more common in women
• Being diagnosed in the teenage years to the 40s is common for Type 1

When to see a doctor

See a doctor urgently if:

• You keep getting headaches, especially at the back of the head, that get worse when you cough, sneeze or strain
• You notice numbness, tingling or weakness in your arms or legs
• You feel dizzy, unsteady, or your balance has changed
• You find it harder to swallow, or you choke more easily than before
• Your child has feeding problems, poor weight gain, breathing pauses in sleep, or is falling behind in development
• You feel very tired, or your snoring has got much worse with daytime sleepiness
• You have new vision problems such as double vision

Book a routine appointment if:

• You already have a Chiari diagnosis and want to talk about your symptoms or a check-up plan
• You are unsure whether your headaches and neck pain need looking into
• You want to discuss whether other family members should be checked
• You have a scan showing Chiari that was found for another reason and you have questions about it
• You want advice on managing daily life, work or exercise with the condition

Diagnosis

Your doctor will start by asking about your symptoms and your medical and family history, and will do a physical examination. This includes checking your nerves, reflexes, balance, coordination, walking, and sometimes your hearing and vision. If your doctor thinks a Chiari malformation is possible, they will usually arrange an MRI scan (magnetic resonance imaging, which uses a strong magnet and radio waves to take detailed pictures of the brain and spinal cord). There is no blood test for Chiari malformation.

Tests that may be done

• Neurological examination: checking your strength, sensation, reflexes, balance and coordination, and how you walk
• MRI scan of the brain and, often, the neck and spinal cord. This is the main test that shows a Chiari malformation
• Cine MRI or MRI flow study: a special type of scan that looks at how fluid moves around the brain and spinal cord
• CT scan of the head or neck in some situations, for example if a child is too young for a long MRI
• Sleep study, if there are breathing pauses, loud snoring or daytime sleepiness
• Hearing and vision checks, or a swallowing assessment, if those areas are affected

What to expect at your appointment

An MRI is painless. You lie still on a bed that slides into a scanner, and it can be noisy, but you can usually have earplugs or music. If you feel anxious or are claustrophobic, tell the team in advance, as there are things that can help. After the scans, you will usually speak to your doctor or a specialist about the results, what type of Chiari malformation it is, whether there are other findings, and whether any treatment is needed. You may also be asked to come back for follow-up scans or check-ups to see whether anything changes over time.

Treatment

Treatment depends on your symptoms, your scan results, your age and your general health. If you have no symptoms, the usual approach is to keep an eye on things with check-ups and scans now and then, rather than treat. If symptoms are mild, the focus is on managing them and keeping life as normal as possible. If symptoms are significant, getting worse, or if there is a build-up of fluid in the spinal cord (called a syrinx), your specialist may discuss surgery. Decisions are always made with you, and a second opinion is reasonable if you want one.

Self-care at home

• Keep a simple symptom diary, noting headaches, balance problems and what seems to trigger them, so you can show your doctor
• Tell your doctor about any activity that makes symptoms worse, and avoid heavy lifting or straining if it sets off headaches
• Ask your doctor or physiotherapist about gentle exercise, posture and neck-strengthening advice that is safe for you
• Get regular sleep and try to keep to a steady bedtime routine
• Ask your employer or school about adjustments if you need them, such as breaks or a different seating set-up
• Check with your doctor before starting high-impact sports, diving, or activities with a risk of head or neck injury
• If you are planning a pregnancy, talk to your doctor early so your care can be planned

Medical treatments

There is no medicine that fixes the structure itself. Treatment is aimed at easing symptoms and preventing problems. Doctors may suggest pain relief for headaches and neck pain, chosen and monitored by your own doctor, along with other options such as physiotherapy, posture advice, and treating problems like sleep apnoea. Some people are referred to a neurologist or neurosurgeon for specialist assessment. If there is pressure from fluid build-up, this is also assessed and managed by specialists. Always ask your doctor or pharmacist before taking any medicine, including over-the-counter ones, and never start or stop a medicine on your own.

When is surgery considered?

Surgery is not needed for most people. It may be discussed if symptoms are significant or getting worse, if everyday life is badly affected, if there is a fluid-filled cavity in the spinal cord (syringomyelia), or if there are signs of pressure on the brain and spinal cord. The most common operation is called posterior fossa decompression. It creates more room at the base of the skull, usually by removing a small piece of bone, and sometimes opening the covering of the brain so fluid can flow better. Surgery can help many people, but it is a big operation with risks and a recovery period, so it is carefully considered together with your specialist team.

Living with this condition

Many people with a Chiari malformation live full, normal lives. Some find that certain things set off symptoms, such as coughing, bending, straining on the toilet, or lifting heavy things. Learning your own triggers and pacing yourself can help a lot. Some people need to adjust their work, study or exercise for a while, and some find that symptoms come and go in phases. It can help to keep a note of what changes, so you can bring it to appointments. Try to keep up your usual activities where you can, with advice from your doctor or physiotherapist.

Lifestyle tips

• Stay active in a way that suits you, such as walking, swimming or gentle cycling, if your doctor is happy with it
• Look after your posture, especially if you sit at a screen for long periods, and take regular breaks
• Avoid straining heavily, for example during lifting, if that triggers your headaches
• Keep well hydrated and eat regular meals, as dehydration and skipping meals can make headaches worse
• Take care with activities that risk knocks to the head or neck, and check with your doctor before contact sports or diving
• Have your eyesight and hearing checked if you notice changes
• Talk to your doctor before long flights or travel if you have symptoms, so you can plan ahead

Diet and exercise

There is no special diet for Chiari malformation, but eating a balanced diet, drinking enough water and keeping to regular meals can help you feel better overall and may reduce headaches. Gentle regular movement helps strength, balance and mood. Ask your doctor or physiotherapist which exercises are right for you. Some people find swimming or walking comfortable, and some prefer physiotherapy-led balance work. Avoid starting anything very strenuous or high-impact without checking first, and stop if something makes your symptoms worse.

Mental health and emotional wellbeing

Living with headaches, pain, tiredness or uncertainty can be hard on your mood. It is completely normal to feel worried, frustrated or low at times, especially around diagnosis or while waiting for results. Talk to your doctor if these feelings are building up, as there is real help available, including talking therapies. If you ever have thoughts of harming yourself or feel you cannot cope, please reach out to a crisis line in your country or your local emergency number straight away, and tell someone you trust.

Prevention

Chiari malformation cannot usually be prevented, because it develops while a baby is growing in the womb. One thing that does help is taking folic acid before and in early pregnancy, which lowers the chance of spina bifida and related conditions; ask your doctor or pharmacist about the right supplement for you. There is nothing you did, or did not do, that caused this.

Screening programmes

There is no routine screening programme for Chiari malformation. Scans are only done when there are symptoms or when something is found for another reason. If someone in your close family has it, talk to your doctor about whether any family members should be checked, as this is decided case by case.

Complications

If left untreated

• A fluid-filled cavity can form inside the spinal cord (called syringomyelia), which can cause numbness, weakness or loss of feeling, especially in the arms and hands
• A build-up of fluid in the brain (called hydrocephalus) can happen, and this needs medical treatment
• Ongoing headaches, neck pain and tiredness that affect work, study and daily life
• Breathing pauses during sleep (sleep apnoea), which can affect energy and heart health over time
• Swallowing problems that can lead to choking or chest infections
• Balance problems that raise the risk of falls
• In serious but uncommon cases, sudden pressure on the brain and spinal cord can be an emergency

Long-term outlook

The outlook is generally good, especially for Type 1. Many people have no symptoms or only mild ones, and never need surgery. For those who do need surgery, many notice an improvement in their symptoms, though some continue to have some symptoms and need follow-up. Most people with a Chiari malformation are able to work, study, exercise and enjoy family life. Regular check-ups, knowing your warning signs and getting help early all help you stay well.

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