Dehydration: Symptoms, causes, and treatments (original) (raw)
Dehydration occurs when more water and fluids leave the body than enter it. Symptoms of dehydration can include darker urine, headaches, lethargy, dizziness, and constipation.
The human body is roughly 60% water. Without this water, it cannot survive. Water is inside cells, within blood vessels, and between cells.
A sophisticated water management system keeps the body’s water levels balanced, and a thirst mechanism tells the body when it needs to increase fluid intake.
Although the body loses water constantly through breathing, sweating, urinating, and defecating, drinking plenty of fluids can replenish it. The body can also move water to areas where it is needed most if dehydration begins to occur.
Dehydration can usually be reversed by increasing fluid intake, but severe cases of dehydration require immediate medical attention.
The first symptoms of dehydration include thirst, darker urine, and decreased urine production. Urine colour is one of the best indicators of a person’s hydration level—clear urine means they are well-hydrated and darker urine means they are dehydrated.
However, it is important to note that, particularly in older adults, dehydration can occur without thirst. This is why it is important to drink fluids regularly, especially when ill or during hotter weather.
As the condition progresses to moderate dehydration, symptoms include:
- dry mouth
- lethargy
- weakness
- headache
- dizziness
- constipation
When people are severely dehydrated they may experience the symptoms above as well as:
- lack of sweating
- sunken eyes
- dry skin
- low blood pressure
- increased heart rate
- fever
- delirium
- unconsciousness
Symptoms of dehydration in babies and young children
- in babies—a sunken fontanel (soft spot on the top of the head)
- dry tongue and mouth
- irritability
- no tears when crying
- sunken cheeks and/or eyes
- fewer wet diapers than usual
- constipation
The basic causes of dehydration are not taking in enough water, losing too much water, or a combination of both.
Sometimes, people do not consume enough fluids because they are busy, lack the facilities or strength to drink, or are in an area without access to drinking water. Additional causes of dehydration include:
- Diarrhea: The large intestine absorbs water from food matter, and diarrhea prevents this from happening. The body excretes too much water, leading to dehydration.
- Vomiting: This leads to a loss of fluids and repeated vomiting makes it difficult to replace lost water.
- Sweating: The body’s cooling mechanism releases a significant amount of water. Hot and humid weather and vigorous physical activity can further increase fluid loss from sweating. A fever can also increase sweating and cause dehydration, especially if there is also diarrhea and vomiting.
- Diabetes: High blood sugar levels cause increased urination and fluid loss.
- Frequent urination: Uncontrolled diabetes can cause frequent urination, but it can also be due to alcohol consumption and medications such as diuretics, antihistamines, blood pressure medications, and antipsychotics.
- Burns: A burn can damage blood vessels, causing fluid to leak into the surrounding tissues.
Although dehydration can happen to anyone, some people are at a greater risk. Those at most risk include:
- people at higher altitudes
- athletes, especially those in endurance events, such as marathons, triathlons, and cycling tournaments
- people with chronic illnesses, such as diabetes, kidney disease, cystic fibrosis, alcohol use disorder, and adrenal gland disorders.
- infants and children—often due to diarrhea and vomiting
Dehydration in older adults is also common. Older adults may wish to drink less water to avoid frequent trips to the toilet.
A doctor can typically diagnose dehydration based on a person’s symptoms.
A blood test may help check kidney function, sodium, potassium, and other electrolyte levels. A urine analysis may also be useful. In a person with dehydration, urine will be darker in color, more concentrated, and contain a certain level of compounds called ketones.
To diagnose dehydration in infants, doctors usually check for a sunken fontanelle on the top of the skull. They may also ask about changes in the infant’s drinking or urination patterns.
People with dehydration should consume certain fluids to restore their fluid levels. Other types of drinks could worsen dehydration. The chart below shows examples of both types of drinks.
People who have lost a lot of fluid due to sickness and diarrhea can drink sports drinks that contain electrolytes. People can also add sachets of electrolyte powder to water. These are available at many stores and pharmacies.
In cases of severe dehydration, people may require intravenous fluids in the hospital to rehydrate.
It is important to treat underlying conditions that may be causing the dehydration. This may include over-the counter medication, such as antidiarrheal or antinausea medications.
Dehydration occurs when people lose more fluid from the body than they consume. People typically lose fluid through urinating, sweating, and breathing, but may lose more when they have vomiting and diarrhea.
Symptoms of dehydration include dark-colored urine, urinating less than usual, headaches, dizziness, and constipation. Severe dehydration can cause mental confusion, low blood pressure, and loss of consciousness.
People should sip fluids to rehydrate but avoid caffeinated and sugary drinks and alcohol.