Which of the following is a symptom of shock?

A rapid pulse is a common symptom of shock, which occurs when the body's circulatory system is unable to deliver adequate blood flow to the tissues. This can happen due to various reasons, such as blood loss, dehydration, or severe infection, leading the heart to compensate by beating faster in an attempt to maintain adequate circulation. The rapid pulse reflects the body’s physiological response to a state of shock, indicating that other vital signs may also be affected, often presenting with low blood pressure and potential changes in consciousness.

In contrast, excessive thirst may occur due to dehydration, which can also be a contributing factor to shock, but it is not a direct symptom of shock itself. High blood pressure typically contrasts with the low blood pressure seen in shock conditions. An intense headache, while it can be linked to various medical conditions or stress, is not specifically indicative of shock. Each of these other options does not directly correlate with the physiological response seen in shock, making a rapid pulse the most appropriate symptom to identify.