Fever

The average body temperature of an individual is 98.6°F or 37.0°C and can vary between 97°F to 100°F. It varies by age, activity and time of the day. This body temperature is not static but keeps changing by about 1-2 degrees during the day. It is lowest in the morning and highest by late evening. It is usually raised under a number of situations like physical activity, strong emotion, eating, heavy clothing, medications, high room temperature, and high humidity. This is more pronounced in children who have a larger surface area for the same weight compared to adults.

The rectal temperature up to 100.4°F (38°C) may be entirely normal and is the most sensitive as it provides us with the core temperature. However, it is rather inconvenient to measure and, hence, we rely more on the oral temperature.

Everyone in his or her lifetime must have had fever. It is when the body temperature crosses the average normal temperature that we label it as fever. Patient or his attendants start worrying when fever occurs and would like it to come down at the earliest.

Let us understand fever or hyperpyrexia.

Fever is not an illness. Far from being an enemy, it is an important part of the body's defense against infection. Many infants and children develop high fevers with minor viral illnesses. While a fever signals to us that a battle might be going on in the body, the fever is fighting for the person, not against.

Most bacteria and viruses that cause infections in people thrive best at 98.6°F. Raising the temperature a few degrees can give your body the winning edge. In addition, a fever activates the body's immune system to make more white blood cells, antibodies, and other infection-fighting agents.

Many parents fear that fever will cause brain damage. Brain damage from a fever generally will not occur unless the fever is over 107.6°F (42°C). Many parents also fear that untreated fevers will keep going higher and higher. Untreated fevers caused by infection will seldom go over 105°F unless the child is overdressed, or trapped in a hot place. The brain's thermostat will stop the fever from climbing above 106°F.

Some parents fear that fever will cause seizures. For the great majority of children, this is not the case. However, febrile seizures do occur in some children. It occurs when the temperature rises fast in a short duration. In any event, simple febrile seizures are over in moments with no lasting consequences.

Although infections are the most common causes of elevated body temperature, fever have a long list of other causes, including toxins, cancers, and autoimmune diseases.

Heatstroke is a particularly dangerous type of high temperature, because the body is not able to stop the temperature from continuing to rise. It can happen when a child is left in a hot car or when you exercise too strenuously without enough to drink.

Unexplained fevers that continue for days or weeks are referred to by doctors as fevers of undetermined origin (FUO/PUO). Most are eventually found to be caused by a hidden infection.

If the fever is mild and no other problems are present, no medical treatment is required. Drink fluids and rest. If a child is playful and comfortable, drinking plenty of fluids, and able to sleep, fever treatment is not likely to help.

Take steps to lower a fever if you or your child is uncomfortable, vomiting, dehydrated, or having difficulty sleeping. The goal is to lower, not eliminate, the fever.

If someone has heat exhaustion or heat stroke, remove the person from the heat source. Sponge the person with tepid water. Place ice packs in the armpits, behind the neck, and in the groin. Give fluids if the person is alert. Seek medical attention. If heat illness is causing the fever, medicines may not lower the body temperature and may even be harmful.

Dr. Rajiv K. Khandelwal
Director & Chief Pediatrician, Vardaan Hospital
Chief Editor, Indian Journal of Clinical and Experimental Pediatrics