Severity

Symptoms

Mild

• Thirst
• Concentrated, dark yellow urine
• Decreased frequency and amount of urination
• Increased pulse
• Vague discomfort
• Fatigue

Moderate

• Dry mouth, lips, tongue and other mucous membranes
• Extreme thirst (polydipsia)
• Low blood pressure
• Little or no urine
• Irritability or restlessness 
• Increased fatigue
• Decreased tears
• Rapid heartbeat (tachycardia)
• Lack of skin elasticity (poor skin turgor)

Severe

• Extreme thirst (polydipsia)
• Very dry mouth, skin, and mucous membranes
• Inability to keep fluids down
• No urine or tears
• No appetite (anorexia)
• Deep, rapid breathing
• Altered mental status
• Weak and rapid pulse
• Skin that is cold and clammy, mottled or hot and dry
• Shriveled and dry skin that lacks elasticity
• Sunken eyes and/or fontanel (the soft spot on top of an infant’s head)
• Lack of sweating
• Low blood pressure
• Rapid heart beat
• Blood clots
• Kidney failure
• Brain swelling (cerebral edema)
• Seizures
• Coma