Case 2: Bizarre behaviour in a three-year-old child

Abstract

A previously healthy three-year-old girl was brought to the emergency room because of a three-day history of abnormal behaviour. The child would wake up at night and start talking to nonexistent people. Throughout these episodes, the child would be awake and would look at her caregivers, but would not respond when spoken to. The mother reported that these episodes were repetitive, occurring throughout the night and that the child had not been getting any sleep. This bizarre behaviour occurred only at nighttime. The patient’s mother reported a history of fever three days earlier and decreased activity. The child was admitted to the hospital for further workup with a provisional diagnosis of ‘acute behavioural change’ to rule out complex partial seizure, acute disseminated encephalomyelitis or herpes simplex encephalomyelitis. Workup showed normal complete blood counts, and normal electrolyte, calcium, phosphorous and magnesium levels. Cerebrospinal fluid studies were normal, including a negative polymerase chain reaction for herpes viruses. The magnetic resonance imaging scan was also normal. A sleep electroencephalogram showed delta activity and episodic slowing. Throughout her hospital stay, the child continued to display the same pattern of abnormal behaviour and occasional abnormal movements manifested by twitching of her arms and lip smacking.