The causes of<unk>  can be characterized into two categories: Kidney * Loss of body sodium and consequent intravascular water (due to impaired reabsorption of salt and water in the tubules of the kidneys) * Osmotic diuresis: the increase in urine production due to an excess of osmotic (namely glucose and urea) load in the tubules of the kidneys * Overuse of pharmacologic diuretics * Impaired response to hormones controlling salt and water balance (see mineralocorticoids) * Impaired kidney function due to tubular injury or other diseases Other * Loss of bodily fluids due to: * Gastrointestinal losses; e.g. vomiting and diarrhea * Skin losses; e.g. excessive sweating and burns * Respiratory losses; e.g. hyperventilation (breathing fast) * Build up of fluid in empty spaces (third spaces) of the body due to: * Acute pancreatitis * Intestinal obstruction * Increase in vascular permeability * Hypoalbuminemia * Loss of blood (external or internal bleeding or blood donation)
Hypovolemia
Dehydration
Hypervolemia
Water intoxication
Hyperosmolar syndrome
Isotonic hyponatremia
Adrenal fatigue
Renal tubular acidosis