What symptom can be classified as a Brief Resolved Unexplained Event (BRUE)?

A Brief Resolved Unexplained Event (BRUE) is defined as an event occurring in an infant that is characterized by a sudden change in tone, breathing, or level of responsiveness, and that resolves quickly without any clear cause. Cyanosis, which is a bluish color of the skin indicating a lack of oxygen, falls under this definition when it presents in an infant and resolves on its own without a lasting explanation.

The key feature of a BRUE is the fact that the event is brief and unexplained, making cyanosis a strong possibility. The other options such as seizure, crying episode, and tachycardia typically have identifiable underlying causes or lead to further investigation because they can indicate other health issues. In contrast, cyanosis can be a transient event, especially in infants, which makes it a potential classification under BRUE when it resolves without an established medical condition.