Objective:

NA

Background:

In recent years, the use of cannabis for recreation and medical conditions has drastically increased. Therefore, the neurologic manifestations of significant cannabis use are still being defined. We describe a case of a patient presenting with seizure and acute encephalopathy, found to have bilateral hippocampal edema, in the setting of cannabis toxicity. This uncommon presentation has been described in few case reports and is important to include on the differential in patients with known cannabis use.

Design/Methods:

NA

Results:

A 73-year-old man presented to the hospital after being found down at home with generalized shaking activity, concerning for seizure.  He was persistently encephalopathic with anterograde amnesia. On arrival, he was hypertensive, tachycardic, tachypneic, and febrile to 103.8F. Labs were notable for WBC 15.2, anion gap 19, CK 232, and lactate 5.9. Urine drug screen was positive for cannabinoids (>750 ng/ml). MRI of the brain showed bilateral hippocampal edema (Figure 1). EEG showed right temporal rhythmic slowing. Lumbar puncture revealed WBC 41 (78% neutrophils), glucose 61, protein 51. Workup for infectious and autoimmune etiologies was unrevealing. Etiology was suspected to be secondary to acute cannabis toxicity. Patient reported routine use of medical marijuana prior to admission but no recent increase in use. The patient's mental status progressively improved over days, and follow up MRI 3 months later showed improvement of the bilateral hippocampal lesions.

Conclusions:

Medical cannabis is comprised of Δ-9-tetrahydrocannabinol (Δ-9-THC) and cannabidiol (CBD) components, which bind to cannabinoid receptors in the brain, including in the hippocampus. Δ-9-THC is a more potent psychoactive compound than other forms. Hippocampal edema from excessive cannabis use can lead to neurologic complications, such as seizures, altered mental status, and amnesia. It is important for clinicians to recognize this uncommon but impactful complication that can result from cannabis toxicity, especially with increased use among the general population.