These are often intense, occur unilaterally around the eye, and are associated with lachrymation, nasal discharge and facial vasodilatation. They are 10 times more common in males than in females, occur particularly between the ages of 40 and 60 years and last for 30-180 min. They are most frequent in spring and autumn when the change in the length of exposure to light is greatest, and are also associated with low plasma peak melatonin and cortisol concentrations.
Seventy-five per cent of cluster headaches occur during sleep and they often appear at the same time each night for several weeks before going into remission. They are most common in REM sleep, and at the transition between REM and NREM sleep. Metabolic activity is increased during these episodes in the cingulate gyrus and hypothalamus close to the supra-chiasmatic nuclei. This probably alters the balance between parasympathetic and sympathetic systems to cause the unilateral vascular and secretory changes which underlie the clinical features. The headaches may worsen during REM sleep rebound when REM sleep suppressant drugs such as tricyclic antidepressants are discontinued, and may be exacerbated by obstructive sleep apnoeas.
Was this article helpful?