Mimicking of cerebral herniation through gamma-hydroxybutyric acid therapy

Besides being a treatment option for narcolepsy, gamma-hydroxybutyrate is used as an adjuvant during anesthesia in Europe. In addition, it is illegally used as a recreational drug. Fixed and dilated, asymmetric pupils developed in 2 patients during continuous therapy with intravenous gamma-hydroxybutyrate, which was added to the long-term anesthetics fentanyl and midazolam. Cerebral herniation as an alternative cause for the pupillary changes was ruled out by using continuous intracranial pressure monitoring and computed tomography. In both patients, the pupillary abnormalities resolved after discontinuation of gamma-hydroxybutyrate. Thus, fixed and dilated pupils that are asymmetric seem to be an important side effect of gamma-hydroxybutyrate therapy that may mimic cerebral herniation in deeply anesthetized patients.