Definition:
Water makes up around 75 per cent of the human body. It’s important for digestion, joint function, healthy skin and removal of waste products.
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Dehydration occurs when more fluid is lost from the body than is taken in. This causes an imbalance in important minerals, such as sodium and potassium, which are required for muscle and nerve function.
If there is a one per cent or greater loss in body weight because of fluid loss, dehydration occurs. This may be mild, moderate or severe, depending on the amount lost.
Infants and children are more susceptible to dehydration than adults because of their smaller body weights and higher turnover of water and electrolytes. The elderly and those with illnesses are also at higher risk.
Dehydration is classified as mild, moderate, or severe based on how much of the body’s fluid is lost or not replenished. When severe, dehydration is a life-threatening emergency.
Who are at Risk?
Anyone’s at risk of dehydration, but some people are more at risk than others.
•Babies and young children have relatively low body weights, making them more vulnerable to the effects of fluid loss.
•Older adults tend to eat less and may forget to eat and drink during the day. With increasing age, the body’s ability to conserve water decreases and a person’s sense of thirst becomes less acute. Illness and disability are also more common, which may make it harder to eat and drink enough.
•People with long-term medical conditions, such as kidney disease and alcoholism, are more at risk of dehydration.
•Short-term, acute health problems, such as viral infections, can result in dehydration because fever and increased sweating mean more fluid is lost from the body. Such illnesses may also make you feel less inclined to eat and drink.
•People living or working in hot climates or those who take part in sports or other strenuous physical activities are at greater risk of dehydration.
Symptoms:
The body’s initial responses to dehydration are thirst to increase water intake along with decreased urine output to try to conserve water. The urine will become concentrated and more yellow in color.
As the level of water loss increases, more symptoms can become apparent. The following are further signs and symptoms of dehydration:
•dry mouth,
•the eyes stop making tears,
•sweating may stop,
•muscle cramps,
•nausea and vomiting,
•heart palpitations, and
•lightheadedness (especially when standing).
The body tries to maintain cardiac output (the amount of blood that is pumped by the heart to the body); and if the amount of fluid in the intravascular space is decreased, the body tries to compensate for this decrease by increasing the heart rate and making blood vessels constrict to try to maintain blood pressure and blood flow to the vital organs of the body. This coping mechanism begins to fail as the level of dehydration increases.
With severe dehydration, confusion and weakness will occur as the brain and other body organs receive less blood. Finally, coma and organ failure, and death eventually will occur if the dehydration remains untreated.
Causes:
Around two-thirds of the water we need comes from drinks. Up to one-third comes from food (tomatoes, cucumber, fish and poultry are good sources). Some is also provided as a result of chemical reactions within the body.
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The average adult loses around 2.5 litres of water every day through the normal processes of breathing, sweating and waste removal. If we lose more fluid than usual this tips the balance towards dehydration.
Your body may lose too much fluids from:
•Vomiting or diarrhea
•Excessive urine output, such as with uncontrolled diabetes or diuretic use
•Excessive sweating (for example, from exercise)
•Fever
You might not drink enough fluids because of:
•Nausea
•Loss of appetite due to illness
•Sore throat or mouth sores
Dehydration in sick children is often a combination of both — refusing to eat or drink anything while also losing fluid from vomiting, diarrhea, or fever.
Lifestyle factors such as drinking too much alcohol, exercise, being in a hot environment or being too busy to drink liquid can also lead to dehydration.
Diagnosis:–
Dehydration is often a clinical diagnosis. Aside from diagnosing the reason for dehydration, the health care practitioner’s examination of the patient will assess the level of dehydration. Initial evaluations may include:
•Mental status tests to evaluate whether the patient is awake, alert, and oriented. Infants and children may appear listless and have whiny cries and decreased muscle tone.
•Vital signs may include postural readings (blood pressure and pulse rate are taken lying down and standing). With dehydration, the pulse rate may increase and the blood pressure may drop because the intravascular space is depleted of fluid. People taking beta blocker medications for high blood pressure, heart disease, or other indications, occasionally lose the ability to increase their heart rate as a compensation mechanism since these medications block the adrenaline receptors in the body.
•Temperature may be measured to assess fever.
•Skin may be checked to see if sweat is present and to assess the degree of elasticity (turgor). As dehydration progresses, the skin loses its water content and becomes less elastic.
•Infants may have additional evaluations performed, including checking for a soft spot on the skull (sunken fontanelle), assessing the suck mechanism, muscle tone, or loss of sweat in the armpits and groin. All are signs of potential significant dehydration.
•Pediatric patients are often weighed during routine child visits, thus a body weight measurement may be helpful in assessing how much water has been lost with the acute illness.
Laboratory testing:-
The purpose of blood tests is to assess potential electrolyte abnormalities (especially sodium levels) associated with the dehydration. Tests may or may not be done on the patient depending upon the underlying cause of dehydration, the severity of illness, and the health care practitioner’s assessment of their needs.
Urinalysis may be done to determine urine concentration – the more concentrated the urine, the more dehydrated the patient.
Treatment:-
As is often the case in medicine, prevention is the important first step in the treatment of dehydration. (Please see the home treatment and prevention sections.)
Fluid replacement is the treatment for dehydration. This may be attempted by replacing fluid by mouth, but if this fails, intravenous fluid (IV) may be required. Should oral rehydration be attempted, frequent small amounts of clear fluids should be used.
Clear fluids include:
•water,
•clear broths,
•popsicles,
•Jell-O, and
•other replacement fluids that may contain electrolytes (Pedialyte, Gatorade, Powerade, etc.)
Decisions about the use of intravenous fluids depend upon the health care practitioner’s assessment of the extent of dehydration and the ability for the patient to recover from the underlying cause.
The success of the rehydration therapy can be monitored by urine output. When the body is dry, the kidneys try to hold on to as much fluid as possible, urine output is decreased, and the urine itself is concentrated. As treatment occurs, the kidneys sense the increased amount of fluid, and urine output increases.
Medications may be used to treat underlying illnesses and to control fever, vomiting, or diarrhea.
Home Treatment:
Dehydration occurs over time. If it can be recognized in its earliest stages, and if its cause can be addressed, home treatment may be beneficial and adequate.
Steps a person can take at home to prevent severe dehydration include:–
•Individuals with vomiting and diarrhea can try to alter their diet and use medications to control symptoms to minimize water loss. Clear fluids often recommended as the diet of choice for the first 24 hours, with gradual progression to a BRAT diet (bananas, rice, apples, toast) and then adding more foods as tolerated.
•Loperamide (Imodium) may be considered to control diarrhea.
•Acetaminophen or ibuprofen may be used to control fever.
•Fluid replacements may be attempted by small, frequent amounts of clear fluids (see clear fluids information in previous section). The amount of fluid required to maintain hydration depends upon the individual’s weight. The average adult needs between 2 and 3 liters of fluid per day.
If the person becomes confused or lethargic; if there is persistent, uncontrolled fever, vomiting, or diarrhea; or if there are any other specific concerns, then medical care should be accessed.
Prevention:-
•Environment: Dehydration due to the weather is a preventable condition. If possible, activities should not be scheduled in the heat of the day. If they are, adequate fluids should be available, and cooler, shaded areas should be used if possible. Of course, people should be monitored to make certain they are safe. Those working in hot environments need to take care to rehydrate often.
•Exercise: People exercising in a hot environment need to drink adequate amounts of water.
•Age: The young and elderly are most at risk. During heat waves, attempts should be made to check on the elderly in their homes. During the Chicago heat wave of 1995, more than 600 people died in their homes from heat exposure.
•Heat related conditions: Know the signs and symptoms of heat cramps, heat rash, heat exhaustion, and heat stroke. Preventing dehydration is one step to avoid these conditions.
Carefully monitor someone who is ill, especially an infant, child, or older adult. If you believe that dehydration is developing, consult a doctor before the person becomes moderately or severely dehydrated. Begin fluid replacement as soon as vomiting and diarrhea start — DO NOT wait for signs of dehydration.
Always encourage the person to drink during an illness, and remember that a person’s fluid needs are greater when that person has fever, vomiting, or diarrhea. The easiest signs to monitor are urine output (there should be frequent wet diapers or trips to the bathroom), saliva in the mouth, and tears when crying.
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.
Resources:
http://www.bbc.co.uk/health/physical_health/conditions/dehydration1.shtml
http://www.medicinenet.com/dehydration/page4.htm
http://www.nlm.nih.gov/medlineplus/ency/article/000982.htm
