Altered Mental Status in a 5-year-old Girl

A 5-year-old fully immunized girl with a history of tuberous sclerosis, localization-related epilepsy with remote resection of a seizure focus, developmental delay, oral aversion with gastrostomy tube dependence, and necrotizing pancreatitis presents with reported episodes of gait instability and altered mental status described as her head falling down, sudden diffuse loss of muscle tone, and unresponsiveness lasting 15 to 45 seconds. During the past few hours, the mother has noticed that the child appears wobbly. She had 1 episode of wobbliness with subsequent fall but denies any head injury, loss of consciousness, or tonic-clonic movements. On presentation to the emergency department she had 2 additional episodes of hypotonia and unresponsiveness to verbal stimuli lasting less than 1 minute. She had not recently missed any of her antiepileptic medications, which included levetiracetam, perampanel, vigabatrin, and taurine. In addition, her medications had not been changed in the past 6 months. Due to...