NCLEX Prioritization, Delegation, and Assignment Practice Test

In hyperthyroidism, the heart is driven to work harder because excess thyroid hormone raises the body's metabolic demands, so a rapid heart rate is a common and potentially dangerous early sign. Tachycardia can quickly progress to more serious problems like atrial fibrillation, heart failure, or a thyroid storm if not recognized and treated promptly, making it the most urgent vital sign change to report right away. While changes in other vitals can be important, they are less specifically tied to the acute risks of thyrotoxicosis. For example, increased respiratory rate can occur with anxiety or infection but isn’t as directly alarming for thyrotoxicosis as a sudden or sustained tachycardia. A decreased oral temperature is not typical of hyperthyroidism and would not point to thyroid-related crisis. Therefore, reporting a rapid heart rate promptly is the most critical action.