Dehydration symptoms, causes and treatment

Dr Adeyemi Maxwell -
Dr Adeyemi Maxwell -

Adeyemi Maxwell

DEHYDRATION occurs when more water and fluids leave the body than enter it, or when you use or lose more fluids than you take in and the body does not have enough water and other fluids to carry out its normal functions. If the fluid deficit is not replaced, then dehydration results. Even low levels of dehydration can cause headaches, lethargy and constipation. Anyone may become dehydrated but the elderly and young children are more susceptible to this condition.

The human body is roughly 75 per cent water. Without this water it cannot survive. Water is found inside cells, within blood vessels and between cells.

A sophisticated water management system keeps our water levels balanced, and our thirst mechanism tells us when we need to increase fluid intake.

Although water is constantly lost throughout the day as we breathe, sweat, urinate and defecate, we can replenish the water in our body by drinking fluids. The body can also move water around to areas where it is needed most if dehydration begins to occur.

Most occurrences of dehydration can be easily reversed by increasing fluid intake, but severe cases of dehydration require immediate medical attention.

Symptoms of dehydration/

water depletion

Dehydration is easy to remedy but can be serious if left unchecked. The first symptoms of dehydration include thirst, darker urine and decreased urine production. In fact, urine colour is one of the best indicators of a person’s hydration level – clear urine means you are well hydrated and darker urine means you 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 more water when ill, or during hotter weather.

As the condition progresses to moderate dehydration, symptoms include: dry mouth, lethargy. weakness in muscles, headache, dizziness

Severe dehydration (loss of ten-15 per cent of the body’s water) may be characterised by extreme versions of the symptoms above, as well as: Lack of sweating, sunken eyes, shrivelled and dry skin, low blood pressure, increased heart rate, fever, delirium, unconsciousness.

Symptoms in children and 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, no wet diaper for three or more hours.

Causes of dehydration

The basic causes of dehydration are not taking in enough water, losing too much water, or a combination of both. Sometimes it is not possible to consume enough fluids because we are too busy, lack the facilities or strength to drink, or are in an area without potable water (while hiking or camping, for example).

Additional causes of dehydration include:

Diarrhoea – the most common cause of dehydration and related deaths. The large intestine absorbs water from food matter and diarrhoea prevents this from happening. The body excretes too much water, leading to dehydration.

Vomiting – leads to a loss of fluids and makes it difficult to replace water by drinking it.

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. Similarly, a fever can cause an increase in sweating and may dehydrate the patient, especially if there is also diarrhoea and vomiting.

Diabetes – high blood sugar levels cause increased urination and fluid loss.

Frequent urination – usually caused by uncontrolled diabetes, but also can be due to alcohol and medications such as diuretics, antihistamines, blood pressure medications and antipsychotics.

Burns – blood vessels can become damaged, causing fluid to leak into the surrounding tissues.

Risk factors for dehydration

Although dehydration can happen to anyone, some people are at a greater risk. Those at most risk include:

People at higher altitudes who work or exercise when it’s hot and humid may risk dehydration and heat illness. This is because when the air is humid, sweat cannot evaporate and cool as quickly as it normally does and this can lead to an increase in body temperature and the need for more fluids.

Athletes, especially those in endurance events, such as marathons, triathlons and cycling tournaments. Dehydration can undermine performance in sports,

People with chronic illnesses, such as diabetes, kidney disease, cystic fibrosis, alcoholism and adrenal gland disorders are often susceptible to dehydration.

Infants and children – most commonly due to diarrhoea and vomiting. Children are more susceptible to dehydration because they have high metabolic needs and have higher insensible loss as they have a higher body surface area.

Dehydration in older adults is common because as they age, the body’s fluid reserve becomes smaller, the body’s ability to conserve water is reduced and the sense of thirst become less acute. Sometimes this also occurs because they drink less water so that they do not need to get up for the toilet as often.

Complications of dehydration

Heat injury. If you don't drink enough fluids when you're exercising vigorously and perspiring heavily, you may end up with a heat injury, ranging in severity from mild heat cramps to heat exhaustion or potentially life-threatening heatstroke.

Urinary and kidney problems. Prolonged or repeated bouts of dehydration can cause urinary tract infections, kidney stones and even kidney failure.

Seizures. Electrolytes – such as potassium and sodium – help carry electrical signals from cell to cell. If your electrolytes are out of balance, the normal electrical messages can become mixed up, which can lead to involuntary muscle contractions and sometimes to a loss of consciousness.

Low blood volume shock (hypovolemic shock). This is one of the most serious, and sometimes life-threatening, complications of dehydration. It occurs when low blood volume causes a drop in blood pressure and a drop in the amount of oxygen in your body.


Most cases of mild to moderate dehydration can be treated by increasing fluid intake and drinking water and different forms of rehydration fluids. However, when dealing with severe dehydration, intravenous fluid therapy at a hospital setting is usually the best course of action.

Contact Dr Maxwell on 3631807 or 7575411


"Dehydration symptoms, causes and treatment"

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