Fever in babies and children

A child with a fever can be a tricky situation for a new parent. Seeing your child in discomfort kicks those ancient primal parenting responses into high gear and we reach for the meds to get rid of the high temperature and return our babies to normal…but is this the right approach?

Fever itself is not an illness. In fact, an increase in body temperature is a great indicator that your child’s immune system has switched on and is fighting off an infection. 36 to 37.6 degrees Celsius is the average normal temperature in babies (although this does fluctuate throughout the day) and anything above 38 degrees is considered fever.

Fever happens because certain cells in your child’s body release chemicals in response to any invading bugs they may encounter. These chemicals move from the infection site to the brain and cause your child’s body to do things like cause more blood to flow to the core, speed up their metabolism (the rate at which they turn food into energy) and cause them to shiver and cry which both create heat through muscle contraction.

But why does having a higher body temperature help defend against infection? For starters, fever slows the activity and growth rate of the invading bugs which gives the immune system a chance to work. High temperatures can kill off certain invaders whilst at the same time speeding up chemical reactions in the body which help to repair damaged cells. Fever also seems to lower the iron levels in the body at the same time as causing the invader bugs to need more of it, effectively starving them out. Fever also has the added bonus of speeding up the heart rate which means your child can get fighting cells to the infection site faster.

The best way to treat a fever is… to find out what is causing it, because although most fevers are caused by viral infections which are well tolerated by young children, some fevers can be caused by serious bacterial infections which cannot be left without treatment. Babies under 2 months of age have immature immune systems and are particularly prone to these type of serious infections, so any fever in this group should be treated as an emergency. That is to say, immediately determine the cause of the fever and not to get rid of the fever itself.

However, the rules of fever change when the temperature reaches over 41.1 degrees. This is almost unheard of in simple infections and is more a result of heatstroke, poisoning or nervous system malfunction. When the body is unable to bring the temperature down from this level the fever stops being positive and can have very negative consequences. This is an emergency situation.

The height of the fever by itself doesn’t necessarily indicate how sick your child actually is. In fact, it can be quite unreliable. Relatively minor infections like colds and flu often produce raging fevers but baby still looks happy whilst other serious diseases produce only a mild fever and a lethargic child. So when it comes to deciding how seriously to take your child’s condition it’s a good idea to look at symptoms other than just temperature. If your baby shows breathing difficulties, not wanting to drink, looking listless or constant inconsolable crying which differs from their normal cry pattern, these are more reliable indicators to take into account that something may be wrong. Use this information when making your decision on how to move forward rather than solely from the numbers on the thermometer.

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Mike Marinus

Mike Marinus

Mike Marinus, dad to Megan and James plus a Chiropractor in Blairgowrie with a special interest in family practice and paediatric care. 

3 Responses

  1. My 4 yr old has been ill almost every month. Mostly virul infections. She is new to being 4 however not new to go too creche(2yrs). This is highly frustrating for me. ..high fevers and time off with her. Any suggestions on immune boosting and will she ever not be I’ll so frequently.

  2. You should also mention about febrile seizures (fever seizures) and what to do if you find yourself in that situation.

    1. Febrile seizure happens in about 4% of children and is a convulsion triggered by fever usually within the first 24 hours of the illness. They can be very frightening but mostly they cause no lasting harm and are not connected to any long term health problems (it is not considered epilepsy). Generally, Febrile seizures will happen to children between the ages of 9 months and five years old and do have a tendency to run in families.

      A simple febrile seizure can last anywhere from a few seconds to 10 minutes and involves both sides of the body, children may cry, moan, vomit or pass urine. The seizure is usually followed by a period of confusion. Be aware however if a child’s seizure lasts longer than 15 minutes, occurs only in one area of the body or occurs twice or more during the same illness, these are not signs of febrile seizure and should be diagnoses as soon as possible.

      If your child has one convulsion, they are at 30 – 40% greater risk of having a repeat episode. This is not affected by medical treatments.

      If your child is seizing, have them unrestrained in your arms or in a bed etc until seizure passes. Keep the head lower than the body, don’t place anything in the mouth (remove dummy).

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