Case Studies in Neuroscience: Transcranial Doppler assessment of increased cerebral blood flow during iterative seizures

Abstract

This case study aimed at monitoring ictal vasodilation in a clinical setting to confirm the experimental data on enhanced cerebral perfusion during epileptic seizures. Clinical observation of a patient presenting relapsing seizures in the intensive care unit. Transcranial Doppler (TCD) was used to monitor both blood velocities and the arterial caliber in the B-flow mode as a proxy of blood flow of the middle cerebral artery (MCA). A 35-yr-old woman experienced partial epileptic seizures lasting for 1 min that recurred every 5 min. Seizures were monitored with continuous EEG and TCD. During the seizure, the MCA caliber increased whereas velocities remained stable, which doubled the MCA blood flow. Immediately after the seizure, the artery caliber returned to its initial value, and the velocities increased by one-third of the initial value. After intensification of antiepileptic treatment, clinical seizures ceased, and TCD findings returned to normal MCA caliber and velocities. Autoimmune encephalitis was identified by brain biopsy and the patient recovered with corticosteroids treatment. This is the first description of ictal vasodilatation assessed by TCD. Our current understanding holds that cerebral blood flow increases during a seizure, but our report demonstrates that arterial dilation preceded the acceleration of velocities. This case study in a clinical setting confirms the impact of seizures on cerebral blood flow. NEW & NOTEWORTHY The case study is a clinical demonstration of ictal vasodilation. By assessing arterial caliber and blood velocities with transcranial Doppler, we dissected the impact of seizures on blood flow of the middle cerebral artery in the following sequence: 1) vasodilation occurred, concomitant to the epileptic activity, whereas the blood velocities remained stable and 2) immediately after the seizure, the velocities increased and the artery caliber returned to its initial value. As per author, there was no protocol, but one patient gave consent to use data from her medical file.

Keywords: B-flow mode; cerebral blood flow; epileptic seizure; middle cerebral artery; transcranial Doppler.