Which symptom is indicative of severe dehydration?

Severe dehydration is characterized by a significant loss of body fluids, which leads to specific physiological changes. The presence of dry mucous membranes and decreased skin turgor is a classic sign of dehydration. Dry mucous membranes indicate that the body lacks sufficient fluid to maintain moisture in tissues, while poor skin turgor, or the skin's ability to return to its normal state after being pinched, reflects inadequate hydration status.

In a dehydrated state, the skin may feel less elastic and does not spring back as quickly after being pinched, providing a clear visual indication of fluid deficit. This symptom is essential in clinical assessments of hydration status and is particularly critical in determining the severity of dehydration.

The other options represent different conditions that are not typical markers of severe dehydration. Increased urination is usually associated with conditions that involve diuresis, which is not expected in severe dehydration; swelling in extremities usually indicates fluid overload or edema rather than a deficit; elevated blood pressure can also be misleading, as dehydration often leads to lower blood pressure due to volume depletion. Hence, the signs and symptoms associated with severe dehydration focus heavily on the lack of fluid rather than the presence of additional complications.