This occurs when there is less fluid in the circulation and body tissues than is needed for proper bodily functions. This can stem from the loss of body fluids due to sweating or excess urination.
The severity of dehydration is gauged by the percentage of body weight lost:
Mild: 3-5% of body loss (infant); 5% of body weight loss (older children)
Moderate: 6-9% of body weight loss (infant); 7% of body weight loss (older children)
Severe: 10 or more % of body weight loss (infant); 10 or more % of body weight loss (older children)
Mild dehydration:
Thirst
Restlessness
Moderate:
Dry mouth
Rapid breathing
Skin tenting (skin loses its recoil)
Lack of tear production
Sunken eyes, anterior fontanel
Low blood pressure
Rapid pulse
Decreased urine production
Severe:
Rapid breathing
Low blood pressure
No urination
Confusion
Coma
Fluid deprivation
Inability to drink liquids
Prolonged heat exposure
Diabetic ketoacidosis
Diabetic hyperosmolar coma
Infections
Large burns (fluid loss through the skin)
Overuse of water pills (diuretics)
Diarrheal illnesses
Prolonged vomiting
A careful history
Body weight measurements
Orthostatic blood pressure measurements(to look for a lower blood pressure when standing, compared to sitting)
Elevated BUN out of proportion to an elevated creatinine
Central venous pressure measurements if diagnosis unclear
Oral crystalloid hydration fluids
Intravenous fluids (Initially, normal saline is usually the most effective)
