When chewing gum is more than just a bad habit

In November, 2008 a 13-year-old boy (weight 45 kg, height 160 cm) was taken by his parents to the emergency department. His parents reported that after school the boy had been agitated and aggressive, in contrast with his normal mood. He denied feeling stressed or having used drugs or stimulants. He complained of abdominal discomfort, increased diuresis, dysuria, and prickling sensations in his legs. On examination, he was restless, with sinus tachycardia (147 beats per min [bpm] on electrocardiogram [ECG]), tachypnoea (25 breaths per min), and raised blood pressure (145/90 mm Hg). Chest radiography and laboratory blood test results were normal. Toxicological screen was negative for cocaine, heroin, and amphetamine. Psychiatric consultation was unremarkable. Our patient’s condition improved overnight without any treatment and he was discharged the following morning. At discharge he was noted to have sinus bradycardia (40 bpm).Later that day, his mother returned to the emergency unit with two empty packets of stimulant (“energy”) chewing gum that she had found in her son’s bag; he had admitted consuming the confectionery at school. The chewing gum contained 160 mg caff eine per packet (0·57% caff eine per gum pellet) and non-specifi ed amounts of guarana