Chronic paroxysmal hemicrania. VII. Mechanical precipitation of attacks: new cases and localization of trigger points.

Two new chronic paroxysmal hemicrania patients are described. In both, attacks can be precipitated mechanically by applying firm manual pressure to certain sensitive points on the neck, i.e. in the C2 area, in the transverse processes of the C4-C5 vertebrae, or beneath the posterior part of the skull on the symptomatic side. The most sensitive area seems to be the transverse process of C4-C5. Susceptibility to this type of attack is dependent on the flow of spontaneous attacks; attacks are easily precipitated in a phase with multiple spontaneous attacks, but are not readily precipitated otherwise. Under indomethacin protection, local tenderness is clearly diminished and attacks cannot be precipitated.