Fever and Beyond

Fever is the body’s natural and healthy response to infection, designed to activate the immune system. Put simply, it is like an emergency siren that goes off once a microorganism entering the body has been detected, so that the cells of the immune system rush to the affected area. As the temperature rises, the growth of bacteria and the multiplication of viruses are slowed down.

Normal body temperature differs with age. In children and babies, body temperature is affected by many external factors. Moving around, being over-dressed or even having a hot drink can raise it. If there is a baby or child at home, there should always be a reliable thermometer in the house. It is important for the caregiver to use this thermometer correctly and interpret the results properly when following an illness. Ear thermometers give the most reliable reading. Roughly speaking, we can consider anything above 38 °C to be a fever.

At what temperature should we give a fever reducer? At what temperature should we worry? At what temperature should we go to the emergency department?

Every parent has asked their paediatrician these questions at least once.

The height of the fever does not correlate with the severity of the illness. Individual characteristics mean that the same illness causes different levels of fever in different people. With the same flu virus, your neighbour’s child may not go above 38.5 °C, while your child’s temperature may reach 40 °C.

Each child also tolerates the same temperature differently. One child may be running around and playing at 39 °C, while another is flat in bed at 38.5 °C. If your child is in good spirits, playing and eating well, you do not need to give a fever reducer for every fever. If the child becomes listless, cries for long periods, is restless or cannot sleep, a fever reducer can be given above 38 °C. Even so, before giving medicine it is recommended to cool the room, remove some clothing and try a lukewarm shower. A fever that reaches 40 °C should be treated with a fever reducer without waiting. It is a fact that fever reducers do not lower the risk of febrile seizures. (Febrile seizures are related to genetic predisposition, leave no damage and do not correlate with how high the fever is.)

During a fever, children’s daily need for fluids, oxygen and energy increases. Heart rate and breathing speed up. For this reason, children with chronic heart or lung disease need a separate assessment; they may need a fever reducer earlier and at lower temperatures to ease the strain on their metabolism. This is also why all children – whether previously healthy or not – are advised to drink plenty of water and get fresh air during a febrile illness.

The table below is very important because it contains information every mother should know – and that makes our job as doctors easier too.

What to Know When Caring for a Child with Fever

1. Fever is a normal physiological response.
2. Fever is a symptom, not a disease.
3. Fever should be approached calmly.
4. Fever may continue until the illness subsides.
5. Body temperature cannot always be measured exactly.
6. Fever is mostly a useful defence mechanism.
7. Fever does not always need treatment.
8. Antipyretics, like all medicines, are chemicals that can have unwanted effects and side effects; like all medicines they should only be used when indicated.
9. How the child looks is always more important than how high the fever is. If there is a rash, if feeding or sleep is disturbed, or if your child does not look well to you, see a doctor without delay.

Lowering Fever Without Medicine

Non-drug methods of lowering a fever include undressing the child, cooling the room, giving a lukewarm shower, and applying compresses with a cloth or cotton soaked in lukewarm water. Compresses with vinegar water are a traditional method, but vinegar has no fever-lowering effect – it is the water that does the work. It is important that compresses or showers are lukewarm, because cold water can trigger the body’s shivering mechanism and make the fever rise even further.

Choosing the Right Medicine

When medicine is needed, choosing the right one matters. First of all, it is important to know that no medicine is completely harmless. Treatment should start with the medicines that have the fewest side effects, and you need to know about them in order to use the right dose at the right intervals.

The first choice should be syrups containing paracetamol. Because of their favourable side-effect profile and wide dosing range, they are used safely at all ages from the newborn period onwards. The treatment dose is 10–15 mg/kg. Since most paracetamol syrups contain 120 mg of active ingredient per measure (5 ml), a baby weighing 10 kg should take one measure. By the same simple calculation, a 15 kg child should take one and a half measures, and a 20 kg child two measures. The dose can be repeated every 4–6 hours, but not exceeding 5 doses a day is an important rule to avoid increasing side effects. Paracetamol syrups (like all medicines) must be stored out of children’s reach at home, ideally in a locked cupboard. Because it is the medicine children use most often, its colour, taste and smell are made very appealing to them, and we frequently see children who find a bottle left lying around and drink the rest of it in one go. Remember that 150 mg of paracetamol per kg is toxic and requires hospital admission because of the risk of acute liver damage. Giving it more often than every 4 hours, or using 90 mg per kg for several days in a row, can have similar effects. Another point to know is that paracetamol is the ingredient most often found in combination medicines. Most cold and flu remedies contain paracetamol, and giving another paracetamol syrup alongside them to control fever can lead to an overdose. Fever-reducing suppositories also contain about as much paracetamol as one measure of syrup.

Although it is regarded as the most harmless medicine, studies have shown that paracetamol use by the mother during pregnancy or in early childhood increases asthma and other allergic diseases later in life; that behavioural problems similar to attention deficit/hyperactivity disorder or hyperkinetic disorders are more common in children of mothers who took paracetamol during pregnancy; and that it reduced the capacity for empathy in laboratory experiments on mice.

Another medicine that can be used to lower fever in children is ibuprofen syrup. Because possible side effects on the kidneys are more common at a young age, it cannot be used in babies under six months. The treatment dose is 5–10 mg/kg. This medicine usually contains 100 mg of active ingredient per measure, so for a child weighing 10 kg, half to one measure is appropriate. Taking 100 mg per kg can be toxic. Even without an overdose it can upset the stomach in some sensitive children. It may also have negative effects on blood clotting, the kidneys, heart, uterus and central nervous system, and can cause allergic reactions.

The most important medicine no longer used to lower fever is aspirin. It is not recommended before the age of 20, when viral infections are common, because it can cause a severe liver disease (Reye’s syndrome).

Medicines containing metamizole lower fever effectively and are therefore preferred by very anxious families, but they are also on the list of medicines that we doctors do not recommend. Their use in children is banned in the USA and the UK. In Brazil, where it is used most widely (it is known as “Brazilian aspirin”), a 2007 study in infants showed that the risk of leukaemia was higher in babies whose mothers used metamizole frequently. Feared side effects include agranulocytosis (reduced production of blood cells), shock, breathing difficulties and a severe reaction with peeling skin (toxic epidermal necrolysis).

In Summary

In light of this information, if non-drug methods have been tried and the fever is still above 38 °C and affecting the comfort of the baby or child, the first-choice medicine should be paracetamol. If the fever persists, paracetamol can be given again at the earliest 4 hours after the first dose. Routinely alternating medicines is not recommended because of the increased risk of side effects. If the fever rises again very quickly despite paracetamol syrup, giving a dose of ibuprofen in between – no more than twice a day – will improve fever control and ease the family’s worries. Giving them more often, routinely alternating paracetamol and ibuprofen every 3 hours, continuing fever reducers after the fever has gone, or waking a peacefully sleeping child because “it’s time for the medicine” is not recommended.

Dr. Görkem ASTARCIOĞLU