Acute toxic reversible amnesia

Abstract

A 34-year-old man with a history of type I diabetes with deficient glycemic controls is brought to the emergency room for sudden anterograde amnesia. He was last seen asymptomatic by a family member 12 h before consultation, after having consumed marijuana and cocaine. On examination, the patient had a Montreal Cognitive Assessment (MoCA) score of 24/30 (− 5 memory, − 1 orientation), without impaired consciousness, neck rigidity or neurological signs, and clinical examination was normal (temperature 36.1 °C, blood pressure 125/78 mmHg). The patient and his family denied fever, chills, myalgias, respiratory symptoms, headache, behavioural manifestations and seizures during the last week. Toxicological screening tests revealed positive results for cocaine and marijuana in urine. Brain MRI showed bilateral cortical hippocampal diffusion restriction with hyperintensity in T2/FLAIR weighted sequences, without abnormal contrast-enhancement or other brain lesions (Fig. 1a, b).