Chiari Malformation

Chiari Malformation is a cause of recurrent, severe headaches, usually provoked by cough, straining (for example at the toilet or when lifting something heavy).

It can also cause a headache when you exercise, or change posture.

Very frequently, the headache due to a Chiari Malformation is a pain in the back of the head.

It is usually a deep dull ache or pressure, but there are a wide range of different headache symptoms. The one thing that would raise suspicion of Chiari is the provocation by cough, exercise, posture, laughter or sneezing.

In a true Chiari headache, the pain is brought on out of the blue by the cough or exercise, then rapidly returns to normal.

This is different to migraine, where there is a moderate to severe background pain which is then worsened by exercise or coughing.

There are also people who have this who experience headaches when they laugh (laughter headaches!).



The presentation can, rarely, be more dramatic with Thunderclap Headache, although I suspect that some of these were probably a new Chiari due to a spinal CSF leak (intracranial hypotension).

A recent case report describes the Neck-Tongue Syndrome in association with a type I Chiari.

The diagnosis is usually made on an MRI brain scan, which shows that the cerebellar tonsils (the lowest lying part of the brain within the skull) have fallen further down into the hole at the base of the skull called the foramen magnum (foramen = hole, magnum = big).

Surgery to free up space at the foramen magnum is usually performed if headache can be attributed to crowding at the foramen magnum.

A secondary cause, such as intracranial hypotension should be considered before offering a surgical procedure.

Spontaneous Intracranial Hypotension should be considered if symptoms suggest that intracranial pressure is low - for example postural headache, tinnitus or muffled hearing.



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