Altered Mental Status in a 5-year-old Girl

Presentation

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 her oral aversion, her mother assures us that she would not have accidentally ingested any medications or other household substances.

Initial temporal temperature is 98.2°F (36.8°C), heart rate is 124 beats/min, blood pressure is 107/77 mm Hg, respiratory rate is 24 breaths/min, and oxygen saturation is 96% on room air. Physical examination reveals a wakeful crying girl fighting medical personnel and intermittently becoming hypotonic and unresponsive to verbal commands. Mucous membranes are moist, and extremities have brisk capillary refill. Respiratory effort is normal except for episodes of periodic shallow breathing. Pupils are midline and reactive but become dilated with minimal responsiveness during the episodes of hypotonia and unresponsiveness. Upper and lower extremity hypotonia is noted (with intermittent worsening during …