Symptoms of dehydration? - Dehydration

The degree of dehydration is graded according to signs and symptoms that reflect the amount of fluid lost:

In the early stages of dehydration, there are no signs or symptoms.
Early features are difficult to detect but include dryness of mouth and thirst.

As dehydration increases, signs and symptoms develop. These include: thirst, restless or irritable behaviour, decreased skin turgor, dry mucous membranes, sunken eyes, sunken fontanelle (in infants), and absence of tears when crying vigorously.

Symptoms of early or mild dehydration include:

flushed face
extreme thirst, more than normal or unable to drink
dry, warm skin
cannot pass urine or reduced amounts, dark, yellow
dizziness made worse when you are standing
weakness
cramping in the arms and legs
crying with few or no tears
sleepy or irritable
unwell
headaches
dry mouth, dry tongue; with thick saliva.

In severe dehydration, these effects become more pronounced and the patient may develop evidence of hypovolaemic shock, including: diminished consciousness, lack of urine output, cool moist extremities, a rapid and feeble pulse (the radial pulse may be undetectable), low or undetectable blood pressure, and peripheral cyanosis. Death follows soon if rehydration is not started quickly.

Symptoms of moderate to severe dehydration include:

low blood pressure
fainting
severe muscle contractions in the arms, legs, stomach, and back
convulsions
a bloated stomach
heart failure
sunken fontanelle - soft spot on a infants head
sunken dry eyes, with few or no tears
skin loses its firmness and looks wrinkled
lack of elasticity of the skin (when a bit of skin lifted up stays folded and takes a long time to go back to its normal position)
rapid and deep breathing - faster than normal
fast, weak pulse