TENSION HEADACHE - BOTULINUM TOXIN PARALYSIS OF TEMPORAL MUSCLES

The pathogenetic mechanism of tension headache (TH) is still unknown. The role of pericranial muscle tension in TH is also enigmatic. To eva luate this factor in chronic TH, pericranial muscles were paralysed in 6 chronic TH patients, using botulinum toxin. All patients fulfilled the IHS criteria of chronic TH associated with involvement of the peri cranial muscles, but not the current criteria for cervicogenic headach e. The patients were followed-up regularly with evaluation of the para lysis, changes in pain intensity, and pressure pain threshold measurem ents. We primarily only injected the temporal muscle on the one side, using the other side as a control. Contralateral muscles were in some cases injected at a later stage. In our study, we did not find any sig nificant reduction in pain intensity, as measured by the visual analog ue scale, nor any changes in pressure pain threshold, as measured by a n algometer. On the basis of our observations, we conclude that muscle tension in these muscles possibly plays a minor role in the genesis o f chronic TH. In our study, however, we have only treated a limited nu mber of patients, and only one pericranial muscle has been injected sy stematically. Further studies of various neck/posterior head muscles o ught to be performed in order to furth er evaluate a possible eff ect of tension in the pericranial musculature in producing this type of pa in.