Dehydration occurs when the body loses more fluids than it is taking in.

In order to function normally, the body needs to maintain a certain internal balance of fluids and electrolytes to carry out its metabolic processes. The body naturally loses water throughout the day and dehydration occurs when the balance is upset as a result of the body losing more fluid than is replaced.

There are many possible dehydration causes, ranging from the everyday such as simply forgetting to drink water or excessive sweating due to hot weather or physical exertion through to physical illness – dehydration from vomiting or diarrhoea is especially common in children.

What are its symptoms?

Dehydration symptoms may vary depending on the severity of the problem and whether they are occurring in adults or children.

Dehydration in babies or children may result in:

  • Drowsiness
  • Decrease in urine output
  • Sunken fontanel (soft spot) on the head
  • No or few tears if crying

Adults may show the following signs of dehydration:

  • Increased thirst
  • Dry mouth
  • Dizziness or weakness
  • Headache
  • Constipation
  • Swollen tongue
  • Decreased urination and urine that is dark in colour

Severe dehydration is a medical emergency that can lead to death if left untreated. It can result in:

  • Delirium
  • Fainting and unconsciousness
  • Seizures
  • Decreased blood pressure
  • Organ failure

How is it diagnosed?

A diagnosis of dehydration can often be reached based on the presence of tell-tale physical symptoms and signs. Your healthcare provider will look for signs such as skin lacking in its usual elasticity, low blood pressure and increased heart rate.

Urinalysis to examine the composition and concentration of the urine can indicate the severity of the dehydration.

Blood tests can also be carried out to measure its haemoglobin (red blood cell) volume – this will be greater when water has been lost from the blood. Additionally, blood tests can help healthcare practitioners ascertain the levels of electrolytes such as sodium and potassium.

What are your treatment options?

For mild dehydration, treatment may require nothing more than increasing your fluid intake. In more severe cases, restoring the body’s internal balance may require replacing both water and electrolytes. Oral rehydration solutions are readily available without a prescription and should be resumed until urine starts turning clearer in colour.

Severe dehydration may require hospitalisation for intravenous fluid and electrolyte replacement, as this will deliver the necessary balance of fluids and salts to the body much faster. In cases where dehydration is related to vomiting or diarrhoea, it may be necessary to treat these with the appropriate medication.

Can it be prevented?

Dehydration prevention is as simple as ensuring that you take in enough fluids throughout the day. In normal conditions, clean water is completely adequate for hydration.

It’s also important to take into account that there are times when you may need to increase your fluid intake, such as periods of exercise or hot weather conditions when sweating is increased and illness (particularly those in which vomiting and diarrhoea are symptoms and fluid is lost).

Ensure that you do not overhydrate though – this can result in a condition called hyponatraemia in which blood sodium levels drop too low.

The accuracy of this information was checked and approved by physician Dr Thomas Blake in December 2015