Fever: A sign, not a diagnosis

A fever is generally considered to be a body temperature of around 38°C or higher

Dr Tendai Zuze
Health Matters
YOU might have heard of fever and wondered what exactly it actually is.
Fever is one of the most common reasons people seek medical attention, but it is important to understand that fever itself is not a disease.
It is usually the body’s response to something else that is happening, most commonly an infection.
A fever is generally considered to be a body temperature of around 38°C or higher.
The rise in temperature is part of the body’s defence system. When the immune system detects an infection, it produces substances that tell the brain to raise the body’s temperature. This can make the environment less comfortable for some germs and helps the immune system work more effectively.
The important thing is that the temperature alone does not tell us what is causing the illness or how serious it is.
Someone with a temperature of 38.5°C may simply have a mild viral infection, while another person with a similar temperature may have malaria, pneumonia or another serious infection. There are many possible causes of fever. Viral infections are probably the most common. Colds, influenza, viral gastroenteritis and many other viral infections can cause fever. Bacterial infections can also cause fever, including pneumonia, urinary tract infections, tonsillitis, skin infections and some intestinal infections.
In Zimbabwe, malaria should always be considered when someone develops an unexplained fever, particularly after spending time in a malaria area.
Malaria can initially look like many other infections, with fever, headache, weakness, body pains, chills, nausea or vomiting. It is therefore important not to assume that every fever is “flu” or a common viral infection. Other infections can also cause fever. These include tuberculosis, typhoid and other gastrointestinal infections, measles and, depending on travel and exposure, diseases such as yellow fever.
The symptoms accompanying the fever and the person’s history are often more useful than the temperature itself.
Sometimes the cause is more obvious.
Fever accompanied by cough and difficulty breathing may point towards a respiratory infection. Fever with burning when passing urine may suggest a urinary infection. Fever with diarrhoea and vomiting may indicate a gastrointestinal infection.
Fever with a rash may occur with several viral illnesses, including measles. A doctor will often use these associated symptoms, together with the examination and sometimes blood or other tests, to work out the likely cause.
One of the biggest mistakes people make is automatically taking antibiotics whenever they develop a fever. Antibiotics do not treat viruses, and many common causes of fever are viral. Taking antibiotics unnecessarily can cause side effects and contributes to antibiotic resistance. The correct treatment depends on the underlying cause.
For most uncomplicated fevers, rest and plenty of fluids are important. Fever can increase fluid loss, particularly when accompanied by sweating, vomiting or diarrhoea.
Paracetamol can be used when appropriate to relieve discomfort and reduce a high temperature. The aim is not necessarily to make the temperature completely normal, but to make the person more comfortable while the underlying illness settles.
There are certain situations where fever should not simply be watched at home. Difficulty breathing, severe weakness, confusion, unusual drowsiness, seizures, severe headache with a stiff neck, persistent vomiting, severe abdominal pain, signs of dehydration, chest pain, or a rapidly worsening condition should prompt urgent medical assessment. A rash that does not fade when pressed should also be treated as a warning sign, particularly when the person is very unwell.
Age also matters. Babies, especially those under three months, deserve particular attention when they develop a fever. A temperature of 38°C or higher in this age group requires prompt medical assessment. Young children can deteriorate more quickly, and parents should pay attention not only to the temperature but also to whether the child is drinking, passing urine, breathing normally and behaving reasonably normally.
Older people also deserve special attention. They may sometimes have a serious infection without developing a very high temperature. A sudden change in behaviour, confusion, weakness, reduced appetite or a general deterioration may be more important than the actual temperature.
Pregnant women, people living with conditions that weaken the immune system, and those with significant chronic illnesses should also have a lower threshold for seeking medical advice when they develop an unexplained fever.