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Why the flu makes you feel so bad (1/14/98)

It's flu season! If Hong Kong or Asian or any other type of little bug associated with influenza catches you, you'll spend a few days with a fever and all the other symptoms that accompany having the flu.

But it isn't the fever that causes your discomfort when you are ill, according to Barbara Holtzclaw, PhD, RN, director of nursing research at The University of Texas Health Science Center at San Antonio. Dr. Holtzclaw explains that when a foreign substance, such as a virus or bacteria, enters the body and forces our own cells to release cytokines, or chemical messengers, it is the cytokines that produce the fever and make us miserable, not the elevated body temperature.

Fever is described as an alteration in the thermal balance of the body caused by the bacterial agents that raise the body temperature. The researcher tells us when we shiver with a fever, the physical exertion drives the body temperature even higher. Shivering plays a role in both the cause and the effect of fever.

"A fever generally goes through an episode that lasts from two to three hours, from beginning to end," Dr. Holtzclaw says. "The fever begins like a wave. It starts low and rises until it reaches the set point, which is the point where the system says this is as warm as you are going to get, and it stays at this point until the cytokine level drops."

Dr. Holtzclaw's early research dealt with thermal regulation and symptoms relating to the patient's thermal comfort, specifically after open heart surgery when the body temperature drops.

"About the time I was completing this research I was approached by a person working with cancer patients who were given a drug called amphotericin B," Dr. Holtzclaw says. "Most patients have a violent reaction to this drug. They shiver uncontrollably and shake with chills. The oncology nurse wanted to know if anything could be done for patients with this type of shivering.

"I found that shaking chills are an enhanced version of chills caused by fever because the drug acts like a foreign body to induce cytokines," she continues. "This means that these patients' thermostats are set at a higher level and the normal room temperature feels too cold. The hypothalamus in the brain gets signals from the skin, so we protected these regions by wrapping their arms and legs with terry cloth towels, because the extremities are more sensitive to heat loss than other parts of the body. It worked. We figured since this intervention was successful in the past with surface-cold neurosurgery patients it might also work with cancer patients. We tried it and found that it worked equally as well."

About this time Dr. Holtzclaw switched her research from studying shivering caused by very cold temperatures to studying shivering caused by a fever. She was soon approached by health care workers who were caring for AIDS patients. They wondered if Dr. Holtzclaw's procedure would help their patients by making them more comfortable. "I didn't know if wrapping the AIDS patients' limbs would make a difference because those patients had fevers with shaking chills that were already in progress prior to our intervention," says Dr. Holtzclaw. "They also have very high levels of disease-related cytokines. But we decided to try and again, the treatment was successful.

"We find when patients come into the emergency room with a high fever, the health care worker's first reaction is to uncover the patient," Dr. Holtzclaw continues. "This isn't what should be done. Really significant differences are seen after wraps have been put on the extremities. The shaking chills then stop. The fever continues to rise in an expected fashion, which means we aren't at the end of the febrile episode, but by intervention with wraps we can better control the shivering and shaking chills and perhaps maintain safer temperature levels."

The researcher explains that it is necessary to take a patient's temperature every two hours instead of only once every eight-hour shift, which is the current custom. Traditional fever patterns, such as a virus-causing fever in the morning and with bacteria, in the evening, are changed with HIV. Some patients have two febrile episodes in between temperature checks.

Cytokines, not elevated temperatures, make us feel tired and sleepy during an illness and cytokines also suppress the appetite. In AIDS patients, cytokines interfere with protein synthesis.

"This creates wasting," says Dr. Holtzclaw. "Cytokines recruit the immune factor during the course of an illness but in AIDS patients, there are diminished immune factors to be recruited. There is also evidence that some beneficial cytokine actions are blocked. This means that AIDS patients have all the bad effects produced by cytokines, such as fever and chills, aching, fatigue and so forth, with few of the positive effects, such as active immune properties."

Dr. Holtzclaw explains that the newer, more positive attitudes about the benefits from fever are consistent with those of the ancient Greeks, who believed that fever maintained balance among the four body fluids. This belief persisted for almost 2,000 years.

"When the origins of fever were discovered, we began to feel that the fever itself was a threat to survival," says Dr. Holtzclaw. "It isn't surprising that this attitude endured because experimental evidence of fever's importance as a host defense response is relatively new. Much of what is known about biochemicals in connection with fever has only emerged within the past 30 years."

Whether Dr. Holtzclaw is wrapping the limbs to prevent shivering in cancer patients with fever caused by amphotericin B, or in immunosuppressed AIDS patients with fevers related to an opportunistic infection, the treatment is the same and equally successful.

"As we get more scientific knowledge at the basic research level," Dr. Holtzclaw says, "those findings must be put into practice, and into nursing care as well."

Contact: Jan Elkins (210) 567-2570