væsketab

Væsketab refers to the loss of body fluids, including water and electrolytes, from the body. It can occur through urine, sweat, stool, vomiting, bleeding, burns, or shifts of fluid into body compartments. Dehydration is the consequence when losses exceed intake, leading to reduced intravascular volume and impaired organ function.

Dehydration is classified by the relative loss of water and electrolytes. Isotonic dehydration is the most common, where water and electrolytes are lost in parallel, causing low circulating volume with normal serum osmolality. Hyponatremic (hypotonic) dehydration involves disproportionate electrolyte loss, while hypernatremic (hypertonic) dehydration involves excessive water loss.

Causes include gastroenteritis with vomiting or diarrhea, fever with sweating, heat exposure, inadequate fluid intake, diuretic use, and certain conditions such as diabetes insipidus. Symptoms range from thirst, dry mouth and reduced urine output to dizziness, rapid heartbeat and low blood pressure; infants and older adults may present with fewer or subtler signs.

Assessment relies on history, intake and output, vital signs, skin turgor, mucous membranes and, when needed, laboratory tests of electrolytes and kidney function. Treatment depends on severity: mild to moderate cases are often managed with oral rehydration solutions; severe dehydration or inability to drink requires intravenous fluids, careful electrolyte monitoring, and medical supervision. Prevention focuses on regular fluid intake and rehydration during illness or heat exposure.