Cluster Headaches (cont.)

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What causes cluster headaches?

The specific cause and anatomic origination of cluster headaches isn't known. MRI studies suggest dilation of the ophthalmic artery during an acute cluster headache, while PET scans reveal activity within the cavernous sinus. However, many patients with other headache types also have revealed abnormalities in similar regions, so these tests aren't definitive. There is some evidence that the hypothalamus may be involved in the recurrence cycle of cluster headaches. Activation of the trigeminal ganglion can cause many changes associated with cluster headache, but the trigger for activation of this region hasn't been identified.

What triggers cluster headaches?

Many patients report their headaches begin while sleeping. Additionally, alcohol can trigger cluster headaches in patients who are in the midst of a cycle. Histamines and nitroglycerin can trigger cluster headaches in patients. Seasonal variation has been described, although this is inconsistent for many patients. Some patients have clusters precipitated by environmental changes or changes in stress or activity levels. Hormonal factors, or menstruation, do not seem to trigger cluster headache. Other risk factors include smoking and a family history of the problem.

How are cluster headaches diagnosed?

The diagnosis of cluster headache is typically made after the history of headaches has been explored and a physical examination is completed. Cluster headaches are unique in their presentation, and often the history is sufficient to make the diagnosis. While no imaging study or specific blood test can confirm the diagnosis of cluster headache, an MRI or CT scan of the brain may be ordered to confirm that there are no other contributing factors that may mimic cluster headache symptoms. In some cases, ophthalmologic evaluation is needed to exclude problems within the eye itself that may be causing symptoms.

Medically Reviewed by a Doctor on 2/2/2015

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