HEALTHNET

What causes fever?

Infections caused by viruses or bacteria are the most common reasons why we are running a fever.

(Posted on 26 October 2006)

Q1. What causes fever?

A1. Infections caused by viruses or bacteria are the most common reasons why we are running a fever.

Humans keep their body temperature within a narrow range so that cellular chemical reactions are carried out efficiently and consistently. To regulate our body's temperature, we have a "thermostat" situated in the "hypothalamus" - which is a small structure at the base of the brain. It has a rich blood supply, and is responsible for looking after many of our vital but unconscious bodily functions, such as appetite and body temperature control.

During an infection, our immune system would release antibodies. They cooperate with white blood cells to get rid of the invading microorganism. The process produces small protein chemical byproducts, called "pyrogens" that circulate in the blood. When the hypothalamus senses the presence of pyrogens, the body's thermostat would be "reset" higher. The patient would feel that he is in a cold environment. Symptoms of fever such as chills and shivering are caused by this phenomenon.

Apart from infections caused by microorganisms, fever can also be a signal of other serious illnesses. Disorders of the immune system often present with unexplained fever. Unexplained fever can also be an early sign of cancer, because some tumor cells can produce pyrogens, or pyrogens may be released by tissue breakdown. Fever can be caused by drugs too.

Q2. When under stress, I may have fever at low temperature for a few days. Why?

A2. The intricate relation between the nervous system and the endocrine system coordinates our response to stress. The adrenal gland is situated above the kidney, and can secrete a number of hormones that are important to prepare our body to cope with stress. Adrenaline, for example, can dilate our airways and cause us breath faster. It also causes the heart to beat quicker and stronger and increases our blood pressure. Cortisol is another hormone that prepares our body's metabolism to cope with impending stress. This hormone plays an important role in our immune response against diseases, and prepares our cells' metabolism to cope with stress.

Stress can cause fever in laboratory animals (rats and other rodents). Many of our bodily functions, such as breathing, heart rate, blood flow, digestion are unconsciously regulated by the "hypothalamus". Scientists have found that stress can alter concentrations of chemicals in the hypothalamus, which may be the cause of stress fever. The hypothalamus is also connected with a network of nervous tissue supplying the adrenal glands.

In human beings, stress can provoke a complex system of response that varies with the individual. It affects our emotions, causing fear, anxiety, anger or sadness and hence changes our behavior and interaction with others. Stress as a primary cause of fever in human beings is not commonly encountered. Some doctors do not believe that it is possible at all.

People under stress may lose confidence in their health and therefore feel sick more readily. Stress can also predispose us to infections and it is the disease that causes fever. If you are running a fever, you should not attribute this to stress. Go and consult your doctor.

Q3. What should I do to treat fever?

A3. When you are running a fever, you should:

Rest in a well-ventilated and cool and quiet environment. Open the windows.
Avoid physical exertion.
Do not wear too many clothes or use heavy blankets. Wear light, loose clothing, just enough to keep you from shaking chills. Never use hot water bottles or electric blankets no matter how cold you feel.
Do not eat too much. Drink plenty of clear cool fluids, such as juices. This would supply your body with enough water, glucose and electrolytes.
Use lukewarm water to wash your face, hands, neck and body frequently. Some people may find ice blocks refreshing.
You would sweat a lot, especially when the fever is going down. Change your bed linen and clothing frequently. Clean, dry cloths would help evaporating away the heat.

You should take your temperature with a reliable thermometer and chart down the time and the reading. Experienced doctors can diagnose many diseases by looking at the temperature chart alone. Tell your doctor if you are experiencing any other symptoms, and note any change in conditions. Try to recall if you have been traveling or have you been in contact with animals and poultry. Note if any members of your family or any of your colleagues are sick.

Antipyretics (medicines that bring down the fever) would help bring down the temperature and make you feel better temporarily. Paracetamol is one of the most commonly used antipyretics. Remember that fever is a signal that something is wrong with your body. The most important thing is to find out what causes the signal, rather than putting down that signal at all costs.

Source: Quality HealthCare