A 3-year-old boy presents to the emergency department (ED) with a 1-day history of irritability and listlessness. According to his parents, he was well until the night before when he began to behave abnormally, becoming excessively tired approximately 2 hours after eating dinner. During the night, the boy slept poorly, sporadically awakening with crying followed by brief periods of calmness. The morning of presentation, he was difficult to arouse with intermittent fussiness and reluctance to ambulate.
The patient's medical and developmental history are unremarkable. A review of systems is negative for headaches, seizures, rash, nausea, vomiting, and abnormal bowel movements. He did not have any new or unusual foods for dinner aside from individually wrapped Halloween candy he had collected while trick-or-treating a week earlier. There are no other unusual ingestions reported, and his parents deny access to any chemicals or medications in the home.
On physical exam, the patient is a well-developed, well-nourished but listless boy with intermittent irritability that is consolable by his mother. The patient appears to be agitated by loud noises, lights, and touch. His temperature is 98.0[degrees]F; heart rate is 130 beats per minute; blood pressure is 106/70 mm Hg; and respiratory rate is 30 breaths per minute. Pupil diameter is 3 mm, equal and reactive to light. Head is normocephalic and atraumatic, and his neck is supple without lymphadenopathy. Cardiac and pulmonary auscultation is unremarkable.
Abdominal exam reveals normoactive bowel sounds and a soft, nondistended abdomen with diffuse tenderness and voluntary guarding but no rebound tenderness. Neurologic exam is limited by participation, but there are no obvious focal neurologic deficits and the patient is able to track across midline without nystagmus. Fundoscopic exam is normal with clearly defined optic discs without papilledema. He has normal muscle bulk, tone, and strength throughout but is unwilling to stand or walk without support. Sensation is intact. The patient is unwilling to cooperate with performing a cerebellar examination.
Complete blood count (CBC), basic metabolic panel, urinalysis, hepatic function panel, and serum acetaminophen and salicylate levels are all normal. A chest x-ray and kidneys/ureters/bladder x-ray series are also normal.
Altered mental status (AMS) in children is characterized by the inability to respond to stimulation at a level appropriate to the child's developmental stage. (1) Children who present with AMS should be assessed for impairment of airway, breathing, and circulation, and stabilized before etiology is...