Chiari malformation

Brain tissue sitting lower than it should. Found on many scans in people with no symptoms, and genuinely disabling in others.

What it is

A condition in which the lower part of the cerebellum extends below the base of the skull into the space where the spinal cord runs.

Type 1, the common form, is often present from birth and may cause no symptoms at all. It is frequently found incidentally on an MRI done for headaches or another reason, and in that situation usually needs nothing but explanation.

**The characteristic symptom, when there is one, is a headache brought on by coughing, sneezing, straining or laughing**, felt at the back of the head, lasting seconds to minutes. That pattern is distinctive and is what distinguishes symptomatic Chiari from an incidental finding.

Some people develop a syrinx, a fluid-filled cavity in the spinal cord, which causes progressive numbness, weakness and loss of pain and temperature sensation in a cape-like distribution over the shoulders and arms, and can cause scoliosis in children. That is the finding that most often prompts surgery.

Type 2 is associated with spina bifida and presents in infancy with breathing and swallowing problems.

Surgery, decompressing the space at the back of the skull, helps cough headache and can stabilise a syrinx. It is less reliable for general headache, fatigue and widespread pain, and expectations need setting carefully.

Signs you might notice

Headache at the back of the head brought on by coughing, sneezing, straining or laughing, lasting seconds to minutes.

Neck pain.

Dizziness, unsteadiness, and difficulty with balance.

Difficulty swallowing, a hoarse voice, or choking.

Numbness, tingling, weakness or clumsiness in the arms and hands.

Loss of pain and temperature sensation over the shoulders and arms, suggesting a syrinx.

Sleep apnoea, and in children, developmental or feeding difficulties.

Urgent: progressive weakness or numbness; new swallowing or breathing difficulty; loss of bladder or bowel control; or rapidly worsening symptoms.

In an infant: breathing pauses, a weak cry, feeding difficulty or a stridor.

How it can affect day-to-day life

Incidental Chiari on a scan causes enormous and often unnecessary anxiety. Many people with a low-lying cerebellum have no symptoms and never will, and being told that plainly is the treatment.

Equally, people with genuine symptoms are frequently dismissed because the finding is common, and end up unheard. Both errors happen and both are avoidable by matching symptoms to the classic pattern.

Cough headache can be limited by avoiding straining, treating constipation, and managing a chronic cough.

Where a syrinx is present, monitoring is important because progression is what causes permanent damage.

Fatigue and widespread pain are common in people with Chiari and often persist after surgery, which is disappointing if surgery has been presented as a cure. Realistic expectations set beforehand matter enormously.

Children with a syrinx and scoliosis need both managed together.

Supporting someone well

Distinguish an incidental finding from a symptomatic one. Ask whether the symptoms fit the classic cough-headache pattern.

Ask for MRI of the whole spine to look for a syrinx, not just the head.

Avoid straining: treat constipation, manage a chronic cough, and lift carefully.

Ask for a neurosurgical opinion where symptoms fit, and about realistic expectations from surgery.

Ask about sleep apnoea assessment if there is snoring or daytime sleepiness.

Get progressive weakness, numbness or continence changes assessed urgently.

For a child with scoliosis, ask whether a spinal MRI has been done; a syrinx is a recognised cause.

Ask for pain and fatigue to be managed in their own right rather than waiting for surgery to fix them.

Where to get help

A GP practice for referral to neurology or neurosurgery.

A specialist neurosurgical centre for treatment decisions.

Urgent assessment for progressive neurological symptoms.

Brain and Spine Foundation run a helpline and cover Chiari and syringomyelia.