The Pathophysiology of Marijuana-induced Encephalopathy and Possible Epilepsy after Ingestion in Children: A Case Series

Background: Ingestion of marijuana in children presents primarily with encephalopathy and potentially, in severe cases, seizures. There is a growing body of evidence supporting the benefit of medical marijuana as an anticonvulsant treatment for intractable seizures. However, there are limited data regarding its proconvulsant effects after ingestion. In this case series, we review the pathophysiology of marijuana encephalopathy and potential seizures after ingestion of marijuana in infants and young children. Case presentation: We summarized the cases of six children who were admitted to the hospital with neurological symptoms and a positive urine test for tetrahydrocannabinol (THC) between 2016 and 2018. The primary symptom was excessive drowsiness, with two children progressing to an unarousable state. Two cases presented after ingesting a marijuana confectionery, and the caregivers in four cases were unaware that marijuana exposure was responsible for the clinical presentation. All cases resolved without sequelae and were investigated by social services. In one case, a 6-year-old child with developmental delay and a previous episode of seizures presented with recurrent seizures and evidence of marijuana exposure. Marijuana was considered a probable cause due its proconvulsant effects, but a subsequent seizure episode with a negative urine THC ruled this out. Conclusion: Physicians should consider the possibility of ingestion of marijuana in infants and young children who present with symptoms of unexplained drowsiness. Marijuana products have the potential to provoke seizures and affect the developing brain of a child. Self-medication with marijuana products should be dissuaded, particularly in households with young children.