Wednesday, September 02, 2015

Demystifying Fever: Fever a friend or a foe?

Wednesday, September 02, 2015

In paediatrics practice one of the commonest reasons for seeking help is fever. Nothing distresses the parents like a febrile illness of their kids.There is a certain element of phobia associated with fever, we can call it fever phobia. Most of it is exaggerated and unfounded.

Fever is body's response, in vast majority of cases, to infection( There are other uncommon ailments which can also cause fever). When ever our body is invaded by infective organisms, mostly viruses, uncommonly bacteria and few others like parasites, fungi etc., the body's defence mechanism produces certain chemicals ( Like interleukins and tumour necrosis factors) which mobilise the defence machinery of the body to go and fight and restrict the invading organisms.

There is a temperature control centre in our brain which acts as a thermostat and does not allow the body temperature to fluctuate much ( our body temperature normally is 1C higher in the evening), even when we are exposed to higher ambient temperature of below a certain degree. These chemicals secreted by the defence mechanism reset the thermostat at higher level, which means our heat production goes up and the heat dissipation comes down, resulting in a higher body temperature. The increase in heat production is effected by increased muscular activity which causes rigors. Rigor occurs because the patient's body is effectively shivering in a physiological attempt to increase body temperature to the new set point. And the decreased heat dissipation is achieved by decreasing the blood supply to skin and thereby reducing heat loss through skin, this leads to cold hand and feet and a feeling of cold, sometimes causing chills. These chemicals also cause some muscle aches and pains and some degree of excessive sleepiness.

The most common ailments which cause fever generally do not cause any body organ damage. Most of the parents are worried about it causing brain damage, which is not true. The brain damage is more likely to occur if there is infection of the brain or meninges which is called encephalitis and meningitis respectively. The other group of diseases likely to cause brain damage are heat diseases like heat stroke, where the body's mechanism fails, the thermostat is not disturbed.

One common ailment which affects 2-4% of children with fever is convulsions with fever.It's fairly common and benign event. Generally lasts less than 5 minutes and does not result in any long lasting adverse effect. Most often, the convulsions have already stopped when the child reaches a health facility. The child recovers to full normalcy. It is the peak of fever which is more likely responsible than the rate of rise of temperature. In almost a quarter of patients these convulsions occur at 38-39 C temperature and many a times before the parents could realise the kid was sick. There definitely is a risk of recurrence and on average 30% kids will have recurrence with subsequent episodes of fever. There is no evidence to suggest that use of fever lowering agents can prevent recurrences. Some remedies to be used at home may be prescribed by your doctors to prevent and treat these episodes.


Because of the normal variation in body temperature, there is no single value that is defined as fever. However, the following are generally accepted values:

  • Rectal temperature above 100.4ºF (38ºC)
  • Oral temperature above 100ºF (37.8ºC)
  • Axillary (armpit) temperature above 99ºF (37.2ºC)
  • Ear (tympanic membrane) temperature above 100.4ºF (38ºC) in rectal mode or 99.5ºF (37.5ºC) in oral mode
  • Forehead (temporal artery) temperature above 100.4ºF (38ºC)

Axillary, ear, and forehead temperature measurements are easier to obtain than rectal or oral temperatures, but they are less accurate and may need to be confirmed rectally or orally in certain children.

Which drugs to use?

The role of fever lowering agents is very clear, to make the child comfortable. So, the end point is not a number to which the temperature should be brought down. It means that if the child is sleeping comfortably there is no great merit in waking up the child to administer drugs. These drugs reset the thermostat to lower levels.

Parents get panicky if the temperature does not touch the base line after giving medicines. Paracetamol is the most commonly used safe drug. It starts having its effect in an hour's time, it's effect peaks at 4-6 hours and the total duration is around 6 hours, necessitating a readmisnistration if required. It lowers the temperature by 1-2ºC, not necessarily bringing it back to normal.Paracetamol is very effective in alleviating pain as well.

The other drug favoured by parents is Ibuprofen, which is equally effective, it should be avoided in a patient whose intake is inadequate and who is voiding less frequently because there is a theoretical risk of kidney injury. It should not be used in babies less than 6 months of age. This drug has longer duration of action as compared to Paracetamol, therefore combining two drugs with different duration of action may not be logical. It can be particularly useful where swelling ( Inflammation) is associated, like joint swelling with fever.

There is no great merit in combining or alternating the above 2 drugs, the duration of action may not match and there may be confusion related to dosing which may result is miscalculations and inadvertent over dosing. The benefit accruing is too small to risk.


Do we normally need sponging for an usual fever? Usually not. Sponging with cold water is counter productive as the blood supply to skin diminishes and patient starts shivering. Sponging with lukewarm or tap water is better than immersing body in cold water. The water should take heat from the body and evaporate, making use of latent heat to effect heat loss. Hydrotherapy is very useful in patients where the thermostat is normal as in heat stroke.

If we decide to sponge the patient, we should use paracetamol about 30 minutes before sponging. If we do not use medicine, any thing that attempts to increase heat loss will cause the body to produce more heat thus off setting the advantage.

When should one get alarmed?

Except in babies less than 3 months of age, where the ability to judge well being is limited, well being is a very reassuring sign that nothing serious is happening. A child becoming active in between fever tells us that nothing is seriously amiss. For a baby below 3 months, before one uses fever lowering agent at home a proper evaluation is a must to exclude serious  bacterial infections. A newborn ( first 28 days) must be evaluated even if he/she appears to be normal.

Persistent vomiting, bloating up of tummy, alteration in alertness, rapid breathing, laboured breathing, refusal to feed, less urination( on an average a child should void 5-6 times a day) and skin rash ( especially red spots or bluish mark), call for urgent attention and evaluation by an expert.

Increase fluids

Having fever can increase a child's risk of becoming dehydrated. To reduce this risk, parents should encourage their child to drink an adequate amount of fluids. Children with fever may not feel hungry, and it is not necessary to force them to eat. However, fluids such as milk (cow's or breast), formula, and water should be offered frequently.If the child is unwilling or unable to drink fluids for more than a few hours, the parent should consult the child's healthcare provider.

Next time around when your kid gets fever, do not stay awake whole night with a thermometer in hand, waking up a comfortably sleeping child to look at the number! The goal of treating fever is to make the child comfortable and not " do what ever one can" to bring it back to normal. Fever is a common symptom, mostly of self limited trivial illnesses.

It is reassuring to learn that fever more often  than not is not in itself a damaging factor, the underlying cause is always important. Fever may not after all always be a foe that we think it is!