SUNCT SYNDROME - ESTIMATION OF CEREBRAL BLOOD-FLOW VELOCITY WITH TRANSCRANIAL DOPPLER ULTRASONOGRAPHY

Four patients with SUNCT syndrome (Short-lasting, Unilateral, Neuralgi form headache attacks with Conjunctival injection and Tearing) were in vestigated with Doppler ultrasonography. Blood flow velocity (VI was m easured in all intracranial arteries during both normocapnia and volun tary hyperventilation in 4 patients outside attacks (2 during remissio n; 2 during bout, but outside attacks) and in 8 healthy individuals. V asomotor reactivity (VMR) was calculated on the, basis of the formula of percentage change in V divided by the reduction in end-tidal PCO2, (PETCO2). Under the basal condition, the patients had a slightly, but non-significantly higher V in the middle cerebral artery (MCA) (P > 0. 1) and lower V in the basilar artery (P > 0.05) than controls. During hyperventilation, a significant reduction in V was observed in the ant erior and posterior cerebral arteries, at a level 1.5-2 SD above that in controls (P < 0.05), but a non-significant difference in VMR in com parison with controls. V-MCA was continuously insonated during spontan eous (n=8) and precipitated (n=4) attacks in one particular patient on different days. Prior to attack, V-MCA was significantly lower on the symptomatic side than on the non-symptomatic side (P < 0.014). V-MCA decreased significantly during spontaneous attacks on both sides (P < 0.01) in comparison with the pre-attack stage. and returned to baselin e before the cessation of attack. Similar findings were made during pr ecipitated attacks. PETCO2, was rather constant throughout the entire attack study. Our data suggest that abnormal cerebral circulation may be part of the SUNCT syndrome. The vascular changes may have underlyin g mechanisms differing from those of the pain.