Headache

A guide to headache causes and treatments

PDFDownload this booklet in PDF format (1096kb)

What causes headache?

The brain itself is surprisingly insensitive to pain, but the membrane surrounding it (called the meninges), and the blood vessels at the base of the brain produce pain when adequately stimulated. Blood acts as a real irritant if it gets onto the outside of these vessels, as seen in a sub-arachnoid haemorrhage, while in meningitis both the meninges and the blood vessels themselves become inflamed. Brain tumours are usually large enough to either distort the blood vessels at the base of the brain or block the circulation of the CSF before they cause headache at all. This is why so many tumours will already have been diagnosed because of earlier symptoms.
What actually happens in a person’s head when migraine, tension-type headache and cluster headache occur is still unclear to doctors. For migraine, many normal signals from the outside, such as light and sound, are unusually amplified. How such mechanisms result in pain is a key question for understanding migraine. What is now reasonably clear is that migraine is not simply due to blood vessel dilation.

The aura symptoms seen before some attacks of migraine are even less well understood. The evidence suggests that there is an electrical disturbance on the surface of the brain which can spread across its surface over the course of 20-30 minutes, and most experts on the subject believe that changes in blood flow which can be seen using sophisticated scanners occur as a result of this disturbance. The reason why this happens in the first place and the way in which it is related to the actual headache are very uncertain at present.
previous chapter | next chapter
Page 5 of 13

Contents