Which of the following is a sign of dehydration?

• A. Tachycardia
• B. Hypotension
• C. Dry mucous membranes
• D. All of the above

Answer: (D)

Dehydration lowers circulating fluid volume and triggers body responses that manifest as signs such as tachycardia, hypotension, and dry mucous membranes. A faster heart rate occurs as the body tries to maintain cardiac output despite reduced volume. If fluid loss is significant, blood pressure can drop because there’s less volume to fill the vessels. Dry mucous membranes reflect reduced hydration of mucosal surfaces from fluid loss. Since all of these can be present with dehydration, selecting all of the above is the best choice. In milder cases you may mainly see tachycardia and dry mucous membranes, while hypotension tends to appear with more severe dehydration.