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Fever and
how to treat it
by Dr. Trisha Macnair
Since ancient
times fever has been recognised as a sign of illness. In 400 B.C.
the Greek physician Hippocrates prescribed the bark and leaves of
the willow tree to relieve fever. These are now known to contain
aspirin-like chemicals.
In the 17th
century Thomas Sydenham (described by some as the "English
Hippocrates") regarded fever as a wholesome reaction of the
body to injury. Some people still see it as a sign that the body
is fighting illness.
Causes of
fever
Fever, or pyrexia to give it its medical name, is caused by the
release of certain chemicals by the immune system, usually as a
result of infection or inflammation. In the past many infections
were rapidly fatal and fever was greatly feared, whether due to
measles, flu or after childbirth. These days we have effective treatments
for most infections. Even so, fever is an important sign that someone
is ill, and a cause should always be established. Other causes include
any condition where there is inflammation, from arthritis to trauma
to inflammatory bowel disease.
Perhaps most frightening are rare tropical haemorrhagic fevers,
mention of which sends whole towns fleeing in Africa. Ebola, for
example, is a highly infectious virus and 90% of those who get it
die. It rapidly breaks down the walls of arteries so that the victim
haemorrhages to death.
Fortunately
these infections are extremely rare, but there is a real risk if
you travel abroad of feverish infections such as malaria. Get advice
before you travel:
Fever of
unknown origin
Sometimes doctors simply can't find the cause of a persistent
fever. Then they call it a fever of unknown origin (FUO or PUO for
"pyrexia of unknown origin"). Special tests may be needed
to pin point the cause and detect hidden abscesses or unusual infections.
About 25% are not due to infection, and other explanations must
be sought - most importantly cancer. About 1 in 5 people with chronic
persistent fever have a tumour. Lymphoma, lung cancer, pancreatic
cancer and primary liver cancer patients often have fever caused
by dead cancer cells or bleeding.
What is a
normal temperature?
Normal body temperatures can vary enormously and is influenced
by factors such as exercise, eating, sleeping and time of day -
being lowest at about 3 a.m. and highest at about 6 p.m.
Average normal
body temperature taken in the mouth is 37°C (or 98.4°F). But anywhere
between 36.5 and 37.2°C may be normal. Normal armpit temperatures
are 0.2 to 0.3°C lower than this.
A temperature
of 38°C or above is usually considered to be a significant fever
- you should measure it again after 2 to 3 hours.
Treating
fever
Not every fever needs medical attention, but if it is a young child,
if the temperature continues to rise, and if there are other worrying
symptoms you may want to talk to your doctor about it.
Otherwise there
are several things you can do to help bring the temperature down
and make the person feel more comfortable - see Box 2
Treating
a fever
• Keep the room at a comfortable temperature, but
make sure that fresh air is circulating.
• Drink plenty of water to prevent dehydration.
• Give ice cubes to suck.
• Take off excessive layers of clothing. Small babies
or children may left in a thin vest.
• Sponge skin surfaces with cool water.
• Give medication regularly:
» Paracetamol as tablets (adults)
or syrup (children).
» Ibuprofen as tablets (adults) or
syrup (children).
» Aspirin: for adults only. Children
under 12 may be at risk from a potentially serious condition
called Reye's syndrome if treated with aspirin. |
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