Pathological Case of the Month

PREVIOUSLY healthy 6-year-old white boy was admitted to the hospital after a second episode of syncope. The first occurred several months before when while racing a sibling, he became limp and unresponsive for less than 5 minutes. On awakening, he was aware of his surroundings, but slept a great deal for the next several hours. He was fine until the day of admission when, while racing another sibling, he collapsed, became unresponsive for less than 5 minutes, and then became awake and alert. His medical history is remarkable for lack of routine immunizations, given his parents' medical convictions. There was no history of seizure disorder or cardiac arrhythmia. Family history was noncontributory.