Medical Matters:A few years ago we had a pet white rabbit, Jack, who spent his nights in a hut in the garage. One night Jack began to shiver violently, and my children, concerned that he was cold, put a hot-water bottle in the hutch.
The next morning Jack was stone cold dead. In retrospect, Jack's shivering was probably due to a fever which wasn't helped by the introduction of a further heat source.
Fever, the raising of the body's thermostat, is a reaction to a number of external insults, most commonly acute self-limiting viral conditions. Although a high temperature, especially in a child, is unpleasant, uncomfortable and occasionally traumatic, it is rarely of significance.
Many misconceptions about fever persist and it is still common to see a shivering febrile child being wrapped in blankets or brought closer to a fire. This "shivering" with fever, or rigor, occurs when the internal temperature is rising and the periphery feels cold due to constriction of blood vessels.
An extreme form of rigor, the febrile convulsion, happens in a child more sensitive to rises in temperature. This is quite distressing to witness but very seldom has any long-term consequences. Parents who are concerned about the chances of epilepsy developing from febrile convulsions need not worry, as the relationship is very tenuous.
It is estimated that 3 per cent of young children will have a febrile convulsion, 3 per cent of these will have more than one, and 3 per cent of these will develop epilepsy. Despite these comforting statistics, some parents have an undue fear of temperature - "pyrexophobia". These fears are generally groundless.
Measuring temperature has never been easier. The mercury thermometer, for reasons of safety and efficacy, has been superseded by several varieties of user-friendly devices from the inexpensive fever strip in which crystals change colour with heat to luxury devices which measure the temperature of the eardrum by infrared measurement.
The hypothalamus is the part of the brain that acts as the body's thermostat. Our temperatures normally fluctuate between about 98 degrees Fahrenheit in the morning and 100 degrees in the early evening.
When someone develops fever, a hormone called prostaglandin enters the hypothalamus and alters the temperature gauge. This change activates increased heat production and reduced heat loss in the body.
Historically, humans have gone to great lengths to reduce fever. Physicians are said to have immersed Alexander the Great in cool baths when he was struck with a febrile illness that eventually killed him. The Greeks used willow leaves, containing a prostaglandin inhibitor, to lessen fever. We now know the leaves contain salicylic acid, the active ingredient in aspirin.
Fever is a symptom, not a diagnosis, and the treatment is straightforward common sense. Remove the child from any heat source, do not wrap her in blankets, clothe her lightly, sponge her with tepid water, and give her a dose of paracetamol or ibuprofen. A fan can also be used.
Aspirin should not be used in children as it has been implicated in Reye's syndrome, a rare but unpleasant neurological disease. There is no risk in bringing a feverish child in a car to a doctor's surgery. Exposure to outside air, especially in cold winter days, often reduces the temperature and eases minds all round. Parents often apologise for bringing the child "under false pretences". Expect a few uncomfortable days while the temperature fluctuates and gradually abates as the infection runs its course. Do not expect that a single dose of paracetamol or antibiotic will "cure" the fever.
Antibiotics are of marginal or no value if the condition is viral but are often prescribed expectantly as clinical differentiation between viral and bacterial illness can be difficult.
If fever persists for a week or so it might be prudent to revisit the diagnosis. If nothing obvious emerges, the fever may be designated as a PUO (pyrexia of uncertain origin) and hospital admission or specialist's advice may be sought, but this is relatively uncommon in paediatric practice.
Reassuringly, often the higher the temperature the better, as it may reflect the immune system's ability to fight infection. In everyday practice, I much prefer to see an actively distressed child with a rip-roaring temperature bawling her head off than an irritable child with a slight fever lying there listlessly who may be brewing up something nasty such as meningitis or pneumonia. Although research shows some 40 per cent of parents regard a high temperature as harmful to children, they should not fear fever - in a curious way it's your friend.
PS: Racked with guilt I took the late bunny to the vet where a postmortem revealed necrotising enterocolitis, a common and fatal but unpredictable condition in rabbitland, and nothing to do with hot-water bottles. I was cleared of all charges of veterinary neglect and cruelty to animals.
Jack now rests in peace in our back garden pet cemetery with Declan and Tom Goldfinger, two ex-cats.
Dr Charles Daly is a general practitioner in Co Waterford.
Dr Muiris Houston is on leave.