New clue on the cause of cluster headaches
New research has prompted calls for a fundamental rethink of what causes a common and debilitating form of headache.
Cluster headache is a sudden and excruciating pain on the side of the head that recurs nightly over periods of weeks or even months and is more likely to be suffered by men than women.
High resolution brain scans have to date found no abnormality in the brain structure of those with cluster headaches, and researchers have believed the cause to be a swelling in the blood vessels at the base of the brain.
But now a team of scientists based in the UK have used a new method of brain imaging called voxel-based morphometry to compare the brains of normal subjects with those suffering cluster headache. They've found an enlargement in a part of the brain called the hypothalamus on the side on which the headache occurs.
"The results indicate that the current view of the neurobiology of cluster headache requires complete revision," say the researchers from London's Insititute of Neurology, in an article published in this week's Nature Medicine.
The discovery of an abnormality in the hypothalamus is significant because this part of the brain regulates daily rhythms like appetite and body temperature, possibly explaining why cluster headaches happen at night.
"People should take a deep breath because we're very close to nailing their condition," the Institute's Professor Peter Goadsby told The Lab. He said that while current treatment is aimed at constricting blood vessels, future treatment could be directed at attacking the underlying problem in the hypothalamus.
"This research gives us a clear roadmap for what nerve cells to turn of," said Australian-born Professor Goadsby.
He also said he felt the findings were "generalisable to migraine and other brain problems".
But an accompanying editorial in the journal comments that the mere fact that the brain region is structurally different does not in itself prove that this is the cause. "The fundamental question is akin to the 'chicken and egg' conundrum," the editorial says. Did the headaches result from they structural abnormality or the other way around?
Professor Goadsby said this could only be resolved by further studies but, "I'm optimistic, this is the egg," he told The Lab.