Abstract

Background
s: The International Headache Society(IHS) headache classification, while widely used throughout the world, has a problem in the definition and classification of the daily and near-daily headache named chronic daily headache(CDH). According to the IHS criteria, a chronic tension-type headache(CTTH) is the only possible diagnosis in patients with CDH. Although several studies have demonstrated that many patients with CDH originally suffered from migraine and their headache has transformed from migraine into a CDH(this type of headache was called transformed migraine: TM), the nosological entity of TM is still disputed. Objective: To demonstrate that TM and CTTH have different pathogenesis, we investigated the cerebral hemodynamics of TM and CTTH by using transcranial Doppler (TCD). Methods: During 6 months, 33 patients with TM and 33 with CTTH, diagnosed according to the second revision of IHS criteria proposed by Silberstein, et al., were gathered. TCD was performed with standard methods to measure the mean flow velocities(MFV) and pulsatile indices(PI) of middle cerebral, anterior cerebral, posterior cerebral, vertebral, distal and proximal basilar, ophthalmic artery, and distal, proximal and siphon portion of internal carotid artery. MFV and PI of TM were compared with those of CTTH by student's t test. Results: MFV of all examined arteries in TM were higher than those in CTTH. The differences in MFV were statistically significant in middle cerebral(p=0.005), anterior cerebral(p=0.05), vertebral(p=0.007), distal internal carotid(p=0.003) and proximal internal carotid artery (p=0.04), respectively. Though there was no statistically significant difference, PI of most arteries were lower in TM than in CTTH. Conclusions: Our results show that the cerebral hemodynamic features of TM are clearly different from those of CTTH. Therefore, we propose that TM should be included as a separate disease entity in the next edition of the IHS classification. Korean Journal of Headache 2(1):41-47, 2001