Dehydration means your body does not have as much water and fluids as it should. Dehydration can be caused by losing too much fluid, not drinking enough water or fluids, or both. Vomiting and diarrhea are common causes.
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
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)
- Loss of appetite due to illness
- Sore throat or mouth sores
- Dry or sticky mouth
- Low or no urine output; concentrated urine appears dark yellow
- Not producing tears
- Sunken eyes
- Markedly sunken fontanelles (the soft spot on the top of the head) in an infant
- Lethargic or comatose (with severe dehydration)
- Heart palpitations
- Muscle Cramps
- lightheadedness (especially when standing).
Exams and Tests
A physical examination may also show signs of:
- Low blood pressure
- Blood pressure that drops when you go from lying down to standing
- Rapid heart rate
- Poor skin turgor -- the skin may lack its normal elasticity and sag back into position slowly when pinched up into a fold by the doctor; normally, skin springs right back into position
- Delayed capillary refill
- Blood chemistries (to check electrolytes, especially sodium, potassium, and bicarbonate levels)
- Urine specific gravity (a high specific gravity indicates significant dehydration)
- BUN (blood urea nitrogen -- may be elevated with dehydration)
- Creatinine (may be elevated with dehydration)
- Complete blood count (CBC) to look for signs of concentrated blood
Drinking fluids is usually sufficient for mild dehydration. It is better to have frequent, small amounts of fluid (using a teaspoon or syringe for an infant or child) rather than trying to force large amounts of fluid at one time. Drinking too much fluid at once can bring on more vomiting.
Electrolyte solutions or freezer pops are especially effective. These are available at pharmacies. Sport drinks contain a lot of sugar and can cause or worsen diarrhea. In infants and children, avoid using water as the primary replacement fluid.
Intravenous fluids and hospitalization may be necessary for moderate to severe dehydration. The doctor will try to identify and then treat the cause of the dehydration.
Most cases of stomach viruses (also called viral gastroenteritis) tend to resolve on their own after a few days.
Can I treat dehydration at home?
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.
Outlook (Prognosis)When dehydration is recognized and treated promptly, the outcome is generally good.
Complications of dehydration may occur because of the dehydration, and/or because of the underlying disease or situation that causes the fluid loss.
Kidney failure is a common occurrence, although if it is due to dehydration and is treated early, it is often reversible. As dehydration progresses, the volume of fluid in the intravascular space decreases, and blood pressure may fall. This can decrease blood flow to vital organs like the kidneys, and like any organ with a decreased blood flow; it has the potential to fail to do its job.
Decreased blood supply to the brain may cause confusion and even coma. If enough organs begin to malfunction, the body itself may fail, and death can occur.
When the fluid loss overwhelms the body's ability to compensate, blood flow and oxygen delivery to the body's vital organs become inadequate and cell and organ function can begin to fail.
Heat-related illnesses and associated complications
In heat-related illness, the body's attempt to cool itself by sweating may cause dehydration to the point that muscles may go into spasm (heat cramps). It is often the muscles that are being stressed that will spasm (for example, in people who work outside in a hot environment, arm and leg muscles may spasm from lifting and moving heavy objects or equipment; in athletes, leg muscles may fail from running). As fluid loss increases, the patient may be so dehydrated that there is not enough water to sweat and heat exhaustion or heat stroke may occur. Heat stroke is a true medical emergency.
In dehydration, electrolyte abnormalities may occur since important chemicals (like sodium and potassium) are lost from the body through sweat. For example, patients with profuse diarrhea or vomiting may lose significant amounts of potassium, causing muscle weakness and heart rhythm disturbances. The doctor is often aware of the fluid and electrolyte balance in the dehydrated patient and may decide to monitor electrolyte levels by checking blood tests. Some examples of symptoms caused by abnormal electrolyte levels include muscle weakness due to low potassium, heart rhythm disturbances due to either low or high potassium, and seizures due to low (hyponatremia) or high sodium. In many patients with dehydration, the kidneys are able to compensate and regulate electrolyte levels.
It is reasonable to remember that dehydration does not occur quickly, and sometimes it may take hours to slowly correct the fluid deficit and allow the electrolytes to redistribute themselves appropriately in the different spaces in the body. If rehydration is done too slowly, the patient may remain hypotensive and in shock for too long. If done too quickly, water and electrolyte concentrations within organ cells can be negatively affected, causing cells to swell and eventually die.
Even when healthy, drink plenty of fluid every day. Drink more when the weather is hot or you are exercising.
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.
Call your doctor if you or your child have the following symptoms
- Not producing tears
- Sunken eyes
- Little or no urine output for 8 hours
- Dry skin that sags back into position slowly when pinched up into a fold
- Dry mouth or dry eyes
- Sunken soft-spot on the top of your infant's head
- Fast-beating heart
- Blood in the stool or vomit
- Diarrhea or vomiting (in infants less than 2 months old)
- Listlessness and inactiveness
Also call your doctor if you are not sure whether your attempts to give your child proper fluids are working.
Also call your doctor if:
- An illness is combined with the inability to keep down any fluids
- Vomiting has been going on for longer than 24 hours in an adult or longer than 12 hours in a child
- Diarrhea has lasted longer than 5 days in an adult or child
- Your infant or child is much less active than usual or is irritable
- You or your child have excessive urination, especially if there is a family history of diabetes or you are taking diuretics