Signs and symptoms of dehydration

Summary

Dehydration occurs when the body loses more total water than it takes in, disrupting normal metabolic processes. Its hallmark symptoms include increased thirst and neurological changes such as headaches, general discomfort, loss of appetite, nausea, decreased urine output (unless another cause like polyuria is present), confusion, unexplained tiredness, and in severe cases seizures. As total body water loss increases, symptoms typically become more severe. Common physical signs include dry mucous membranes, dry axillae, increased capillary refill time, sunken eyes, and poor skin turgor. More extreme dehydration can also cause orthostatic hypotension, dizziness, weakness, and altered mental status. In older adults, thirst may be blunted and fatigue is often the most common presenting symptom, while severe dehydration can lead to serious complications such as low blood volume shock (hypovolemic shock), coma, and heatstroke.

Key Points

• 1

  Hallmark dehydration symptoms include thirst plus neurological changes (e.g., headache, confusion, tiredness) and decreased urine output.

• 2

  Physical exam findings often include dry mucous membranes, sunken eyes, and poor skin turgor; severe dehydration can cause orthostatic hypotension and seizures.