DEHYDRATION
Dehydration is defined
as excessive loss of water from the body. Body requires certain amount of fluid
intake daily
for normal functions. Minimum daily requirement of water intake is
about 1 L. This varies with the age and activity of the
individual. The most active individuals need 2 to 3 L of
water intake daily. Dehydration occurs when fluid loss is more than
what is consumed.
Classification
Basically, dehydration is of three
types:
1. Mild
dehydration: It occurs when fluid loss is about 5% of total
body fluids. Dehydration is not very
serious and can be treated easily by
rehydration.
2. Moderate
dehydration: It occurs when fluid loss is about 10%.
Dehydration becomes little serious
and immediate treatment should be
given by rehydration.
3. Severe
dehydration: It occurs when fluid loss is about 15%.
Dehydration becomes severe and
requires hospitalization and emergency
treatment. When fluid loss is more than 15%, dehydration
becomes very severe and life threatening.
On the basis of ratio between water loss and sodium
loss, dehydration is
classified into three types:
1. Isotonic
dehydration: Balanced
loss of water and sodium as in the case of diarrhea or vomiting.
2. Hypertonic
dehydration: Loss
of more water than sodium as in the case of fever.
3. Hypotonic
dehydration: Loss
of more sodium than water as in the case of excess use of diuretics Causes
1. Severe diarrhea and vomiting due to
gastrointestinal disorders
2. Excess urinary output due to renal
disorders
3. Excess loss of water through urine
due to endocrine disorders such as diabetes mellitus, diabetes
insipidus and adrenal
insufficiency
4. Insufficient intake
of water
5. Prolonged physical activity without
consuming adequate amount of water in hot environment
6. Excess sweating leading to heat
frustration (extreme loss of water, heat and energy). Severe
sweating and dehydration occur while
spending longer periods on regular basis in the saunas
7. Use of laxatives or diuretics in
order to lose weight quickly. This is common in athletes.
Signs and Symptoms
Mild
and moderate dehydration
1. Dryness of the mouth
2. Excess thirst
3. Decrease in sweating
4. Decrease in urine formation
5. Headache
6. Dizziness
7. Weakness
8. Cramps in legs and arms.
Severe
dehydration
1. Decrease in blood volume
2. Decrease in cardiac output
3. Low blood pressure
4. Hypovolemic cardiac shock
5. Fainting.
Very
severe dehydration
1. Damage of organs like brain, liver
and kidneys
2. Mental depression and confusion
3. Renal failure
4. Convulsions
5. Coma.
Dehydration in
Infants
Infants suffering from severe diarrhea
and vomiting caused by bacterial or viral infection, develop dehydration. It
becomes life threatening if the lost body fluids are not replaced. This
happens when parents are unable to recognize the signs.
Aging Effects on
Dehydration
Elders are at higher risk for
dehydration even if they are healthy. It is because of increased fluid
loss and
decreased fluid
intake. In some cases, severe dehydration in old age may be fatal.
Treatment
Treatment depends upon the severity of
dehydration. In mild dehydration, the best treatment is drinking of water and
stopping fluid loss. However, in severe dehydration drinking water alone is ineffective because
it cannot compensate the salt loss. So the effective treatment for severe
dehydration is oral rehydration therapy.
Oral
rehydration therapy
Oral rehydration therapy
(ORT) is the treatment for dehydration in which a oral
rehydration solution (ORS) is administered orally. ORS was formulated by
World Health Organization (WHO). This solution contains anhydrous glucose,
sodium chloride, potassium chloride and trisodium
citrate.
In case of very severe dehydration,
proper treatment is the intravenous administration of necessary water and electrolytes.
WATER INTOXICATION OR
OVERHYDRATION
Water intoxication is the condition
characterized by great increase in the water content of the body. It is also
called overhydration, hyperhydration, water excess or water poisoning.
Causes
Water intoxication
occurs when more fluid is taken than
that can be excreted. Water
intoxication due to drinking
excess water is rare
when the body’s systems are
functioning normally. But there are
some conditions that
can produce water intoxication.
1. Heart failure in which heart cannot
pump blood
properly
2. Renal disorders in which kidney
fails to excrete
enough water in urine
3. Hypersecretion of antidiuretic
hormone as in the
case of syndrome of inappropriate
hypersecretion
of antidiuretic
hormone (SIADH)
4. Intravenous administration of
unduly large amount
of medications and
fluids than the person’s body
can excrete
5. Infants have greater risk of
developing water intoxication in the first month of life, when the
filtration
mechanism of the kidney is
underdeveloped and cannot excrete the fluid rapidly
6. Water intoxication is also common
in children having swimming practice, since they are more prone to
drink too much of water while swimming
7. An adult (whose heart
and kidneys are functioning normally) can develop water intoxication, if the
person consumes about 8 L of water
everyday regularly.
Signs and Symptoms
1. Since the brain is more vulnerable
to the effects of water intoxication, behavioral changes appear
first
2. Person becomes drowsy and
inattentive
3. Nausea and vomiting occur
4. There is sudden loss of weight,
followed by weakness and blurred vision
5. Anemia, acidosis, cyanosis,
hemorrhage and shock are also common.
6. Muscular symptoms such as weakness,
cramps,
twitching, poor coordination and
paralysis develop
7. Severe conditions of water
intoxication result in:
i. Delirium (extreme
mental condition characterized by confused state and illusion)
ii. Seizures (sudden
uncontrolled involuntary muscular contractions)
iii. Coma (profound
state of unconsciousness, in which the person fails to respond to external
stimuli and cannot
perform voluntary actions).
Treatment
Mild water
intoxication requires only fluid restriction. In very severe cases, the treatment
includes:
1. Diuretics to increase water loss
through urine
2. Antidiuretic hormone
(ADH) receptor antagonists to prevent ADH-induced reabsorption of water from
renal tubules
3. Intravenous administration of
saline to restore sodium.
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