A 33-month-old with fever and altered mental status

A 33-month-old girl presented with 3 days of fever and 1 day of multiple paroxysmal episodes of screaming with apparent unresponsiveness, flexed lower extremities, clenched hands, and upward eye deviation. These events lasted seconds to a minute at a time and occurred only during sleep. She slept peacefully between episodes and was easily awakened. She had a history of mild speech delay and mild intermittent asthma but was otherwise healthy. She was tired-appearing and fussy on examination with dry mucous membranes, but her examination was otherwise normal. A complete blood count with differential and serum levels of sodium, potassium, chloride, and calcium were normal, but her bicarbonate level was 12 mmol/L. Her fingerstick glucose level was 69 mg/dL. Urine dipstick was notable for large ketones, and a urine drug screen was normal. Cerebrospinal fluid examination yielded 2 white blood cells and 1040 red blood cells/mm(3) with normal chemistries. A computed tomography (CT) scan of her head was unremarkable, and an abdominal ultrasound demonstrated no evidence of intussusception. Over the course of her hospitalization, these paroxysmal episodes persisted, and she subsequently developed mutism, right-sided weakness, and difficulty swallowing liquids. Here we present her case, diagnostic evaluation, and ultimate diagnosis.