Fever, enemy or friend?

1987/10/01 Agirre, Jabier - Medikua eta OEEko kidea Iturria: Elhuyar aldizkaria

• Osasuna

We have to consider our body as a casserole, with its thermostat. When the microbes attack us, the pot begins to boil. It is then when the fever rises with all the symptomatology it carries: you think the head is going to jump, the pulse begins to dance, the sweat will wet the sheets. Much thirst. You're hungry, but it's a hunger without a desire to eat. The heat is semi-slipped, but at the same time a tremor for the chills will sacrifice you from top to bottom. There is no doubt that at night you have had a fever and the thermometer will ensure the diagnosis.

Most of us suffer from such events. But, what is fever after all? An alarm signal that predicts a disease, a defensive reaction of the body or both at a time? Among people, and also among doctors, opinions do not coincide. For some, fever is a perverse perverse enemy who must fight anyway. For others, however, it is nothing more than a resource that nature has provided us to act against diseases.

The man, who is an animal of hot blood, is usually kept at a temperature of about 37ºC, burning in exercise the heat reserves that enter us with food. When the environment cools down, the machine heats more (moving muscles, and perspiration decreases, decreasing the temperature with all this. But when physiology is not enough, we will use external resources (a jumper or hot milk). To combat heat, it happens exactly the opposite: the body generates its own energy (movements, etc.) cushion and subsequently increases heat loss, increasing perspiration. That's why we have sweat when it's hot.

Normally a pot needs the help of a thermostat to function properly. Recent studies indicate that the thermostat of the human body, thermal regulation center, is located in the central nervous system, the hypothalamus. Through the nerve impulses and circulation of the hypothalamus, the hypothalamus receives constant information to avoid alterations of the blood in the skin. And according to this data it launches its thermosensory cells so that the body temperature is kept as close as possible to the 37ºC.

When fever appears, the hypothalamus thermostat is regulated at 39.65 °C instead of at 37 °C. Therefore, the body receives the order to raise its temperature. But if the machine is heated more, there is a risk of major slaughter. Blood pressure from 40.5°C cannot be maintained at a normal level. Dehydration caused by excessive perspiration produces a sudden decrease in body tone with high odds of a heat stroke (seizures, delirium, vomiting, gain, etc. ).

If we exceed 42°C (somewhat below in the case of young children), nerve cells in the brain are destroyed and death arrives. Fortunately, these cases are very rare and there are more deaths from infection than from excessive fever.

Fever is, therefore, a mechanism of regulation. It is usually a mechanism that is launched when a pathogen agent is exhausted. Fever cushions and slows down the attack of microorganisms (bacteria and viruses). For example, polio virus spreads 250 times faster to 37ºC than 40ºC. At the same time, as it inhibits the cult of microorganisms, it accelerates the defense mechanisms of the patient.

Therefore, as fever has its advantages and has been seen in vertebrates for millions of years, from the evolutionary point of view, one can think if its benefits are not going to be greater than the damage. In nature there is nothing in vain. This raises another question: Against the fire, yes or no? This is a topic for another day.