Abstracts

Rationale: Patients with medication resistant epilepsy are evaluated for epilepsy surgery to palliate or cure disabling seizures. Surgical candidates require extensive evaluation including invasive intracranial monitoring to localize the epileptogenic zone. We present two cases of psychiatric complications in patients with anxiety disorder and chronic, daily cannabis use undergoing invasive intracranial monitoring. Methods: Clinical data was abstracted from the patients’ medical record.Case 1:  Patient is a 31-year-old right-handed man with nonlesional left temporal lobe epilepsy, major depressive disorder, and generalized anxiety disorder. He moved to Colorado in 2018 for medical care and to seek legal cannabis for self-treatment of his epilepsy. He smokes cannabis flower and uses CBD oil daily, reporting cannabis improves his mood, anxiety, and seizures.  The patient was advised to discontinue cannabis use prior to surgery by his neurologist and psychiatry consultation performed as a standard part of the presurgical evaluation process.  He reported a trial off cannabis 2 days prior to admission with no adverse effects.On hospital day 1, the patient became significantly anxious and agitated in the absence of seizures.  He demanded removal of his electrodes and discharge from the hospital.  The patient’s behavior continued to escalate, requiring a capacity evaluation and consultation by addiction medicine.   Trials of hydroxyzine and gabapentin were unsuccessful.  The patient ultimately responded to quetiapine with addition of lorazepam following seizure provocation.Case 2:  Patient is a 24-year-old right-handed woman with a learning disability, adjustment disorder with anxiety, methamphetamine use disorder in early remission, and right temporal lobe epilepsy in the setting of periventricular nodular heterotopia.  She smokes cannabis flower twice daily to self-treat her seizures and uses CBD oil to abort seizures based on recommendations from epilepsy websites.  Standard presurgical psychiatry consultation recommended marijuana discontinuation prior to surgery, however the patient did not follow this recommendation.On hospital day 1 the patient became increasingly agitated in the absence of seizures.  While arguing with family, she removed her IV and threatened to pull out her electrodes.  She required physical restraint, haldol and lorazepam IM.  Psychiatry determined the patient lacked decision making capacity. The patient’s mood and agitation improved with scheduled risperidone and resumption of her antiseizure medications including gabapentin and clobazam. Results: Surgical treatment carries inherent risk to the patient. These cases demonstrate additional risks in a subset of epilepsy patients using chronic cannabis for self-treatment of epilepsy. Abrupt cessation of cannabis use in chronic cannabis users with underlying mood or anxiety disorder may significantly exacerbate anxiety and agitation during elective EMU admissions. In extreme circumstances the physician's ability to act in the patient's best interest may be compromised should patients lack decision making capacity. Further, the care team has limited options for anxiolytic control provided the effects of benzodiazepines and gabapentin on seizure threshold should seizure provocation be desired. Conclusions: The increased access to highly commercialized cannabis containing products is appealing to patients and families, and it is frequently used without advisement from physicians. Cannabis withdrawal with added acute stress of brain surgery and seizure provocation should be taken very seriously as the consequences may be life threatening. We recommend that the presurgical process for epilepsy surgery involves a designation of a medical power of attorney, extensive patient education surrounding the hospitalization, and period of abstinence from cannabis, confirmed by urine toxicology. Funding: No funding