Evaluation of postictal optic nerve sheath diameter at epileptic patients

During a seizure, metabolic rate and, consequently, cerebral blood flow increase to provide the required maintenance energy. It is thought that this causes an increase in intracranial pressure, but there is no comprehensive research on this subject. In this study, we aimed to measure and follow optic nerve sheath diameter (ONSD) in patients who applied to the emergency department (ED) after generalized tonic-clonic (GTC) seizures and to gain information about intracranial pressure changes in epilepsy patients in the postictal period.

This was a prospective observational study. Patients already diagnosed with epilepsy who applied to the ED within one hour after GTC seizures were included. The ONSD of the patients was measured by the same radiologist three times in both eyes using ultrasonography at the time of admission and the fourth hour of follow-up. The seizure characteristics and measurements of the patients were recorded, and the changes in ONSD over time and correlations between seizure characteristics and ONSD were examined.

Sixty-six patients were included in the study. Thirty-four (51.5%) of the patients had seizures with auras. For both eyes, the first-hour ONSD values of the patients [right: 5.90 (5.73-6.16) mm, left: 5.86 (5.73-6.13) mm] were significantly higher than the fourth-hour ONSD values [right: 5.26 (5.19-5.40) mm, left: 5.28 (5.16-5.36) mm)] (p < 0.001 for both eyes). Additionally, the first- and fourth-hour ONSD values of patients with seizures with auras were significantly higher than those with seizures without auras (p < 0.001 for each condition). There was no correlation between other variables related to seizure type and ONSD.

This study showed that after GTC seizures in epilepsy patients, ONSD increases in the first hour postictal and decreases over time. Another important result is that the increase in ONSD values in seizures with auras is significantly higher than in seizures without auras.