Volume depletion, or extracellular fluid (ECF) volume contraction, occurs as a result of loss of total body sodium. Causes include vomiting, excessive sweating, diarrhea, burns, diuretic use, and kidney failure. Clinical features include diminished skin turgor, dry mucous membranes, tachycardia, and orthostatic hypotension. Diagnosis is clinical. Treatment involves administration of sodium and water.