Cluster headache and bradycardia.

SYNOPSIS A case of classic cluster headaches associated with paroxysmal bradycardia and hypertension is presented. This case suggests that dysfunction in the medulla oblongata is the primary event in cluster headache. A preliminary hypothesis is discussed which attributes the pathogenesis of cluster headache to a burst of increased central a-adrenergic activity while migraine involves an analogous burst of b-adrenergic activity.