Which finding is more indicative of a hypoglycemic episode?

A rapid onset of altered mental status (AMS) is indeed indicative of a hypoglycemic episode. Hypoglycemia occurs when blood glucose levels drop significantly, leading to a lack of glucose available for the brain, which relies heavily on it for energy. The brain's immediate response to low glucose levels can manifest as confusion, irritability, or a rapid change in consciousness, which characterizes the altered mental status seen in hypoglycemic patients.

In contrast, bradycardia is more associated with other conditions, such as increased intracranial pressure or certain types of heart conditions, rather than with hypoglycemia. A blood glucose level of 569 mg/dL points toward hyperglycemia, indicating high blood sugar rather than a deficiency. Dry mucous membranes typically suggest dehydration or conditions related to a lack of fluid, which are not directly indicative of low blood sugar levels. Thus, the rapid onset of AMS is the most consistent and clear indicator of a hypoglycemic event.