Cerebral blood flow during ACTH therapy: especially diurnal changes within the first week of therapy.
Changes in cerebral blood flow (CBF) were evaluated in children with epilepsy treated with adrenocorticotrophic hormone (ACTH) by the Doppler ultrasound method. The average maximal blood velocity (A/L) and maximal end-diastolic blood velocity (d) of the internal carotid artery, as indices of CBF, significantly decreased during ACTH therapy. These values had already decreased at 30 minutes after the first injection of ACTH and were hardly restored 24 hours later just before the next injection. Such changes repeatedly occurred for the first four days of therapy so that the reductions in the A/L and d values proceeded in a stepwise manner. These values became minimum at around one week after initiation of the therapy and then gradually increased, returning to the original levels by the 8th week of therapy. Investigation of the changes in cerebral metabolism seemed to be the next step for elucidation of the mechanism underlying the CBF reduction during ACTH therapy.