Fever (Salem Health: Cancer)
Related conditions: Infection and sepsis in cancer treatment, myelosuppression, neutropenia
Definition: Fever is a pyrogen-mediated elevation of the core body temperature. This is in distinction to hyperthermia, which is an unregulated rise in core temperature as occurs in heat stroke. Pyrogens may originate outside the body (exogenous) or be produced within the body (endogenous). The exogenous pyrogens are typically microorganisms or their toxins and products but also include drugs, antigen-antibody complexes, and other substances. Endogenous pyrogens are various chemicals produced by host cells and are called cytokines.
Risk factors: Fever may be caused by cancer. Although many types of malignant neoplasms may cause fever, some of the most common are lymphomas, leukemias and preleukemias, and renal cell carcinoma. However, fever in cancer patients is more often a consequence of treatment than of the cancer. The protective barrier provided by the skin and mucous membranes may be breached by surgery or vascular catheter placement, providing entrance points for invading microbes, which produce infection and fever. A similar phenomenon may result from chemotherapeutic cancer drugs that destroy not only the cancer cells but also oral and mucous membrane lining cells, inducing mucositis. Drugs may also kill bone marrow cells (myelosuppression and neutropenia), which impairs bodily...
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For Further Information (Salem Health: Cancer)
Chang, Jae C., and H. Bradford Hawley. “Neutropenic Fever of Undetermined Origin (N-FUO): Why Not Use the Naproxen Test?” Cancer Investigation 13 (1995): 448-450.
Cunha, Burke A., ed. “Fever.” Infectious Disease Clinics of North America 10 (1996): 1-222.
Dinerello, Charles A., and Jeffrey A. Gelfand. “Fever and Hyperthermia.” In Harrison’s Principles of Internal Medicine, edited by Dennis L. Kasper et al. 16th ed. New York: McGraw-Hill, 2005.
Mackowiak, Philip A., ed. Fever: Basic Mechanisms and Management. 2d ed. Philadelphia: Lippincott Williams & Wilkins, 1997.
Murray, Henry W., ed. FUO: Fever of Undetermined Origin. New York: Futura, 1988.
(The entire section is 91 words.)
Other Resources (Salem Health: Cancer)
American Cancer Society. Fever. http://www.cancer.org/docroot/MBC/content/MBC_2_3X_Fever.asp?sitearea=MBC
National Cancer Institute. Fever, Sweats, and Hot Flashes. http://www.cancer.gov/cancertopics/pdq/supportivecare/fever/Patient/page2
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Causes and Symptoms (Magill’s Medical Guide, Sixth Edition)
Although the symptoms that often accompany a fever are familiar to everyone—shivering, sweating, thirst, hot skin, and a flushed face—what causes fever and its function during illness are not fully clear even among medical specialists. Considerable literature exists on the differences between warm-blooded organisms (endotherms) and cold-blooded organisms (ectotherms) in what is called the normal state, when no symptoms of disease are present. Cold-blooded organisms depend on temperature conditions in their external environment to maintain various levels of temperature within their bodies. These fluctuations correspond to the various levels of activity that they need to sustain at given moments. Thus, reptiles, for example, may “recharge” themselves internally by moving into the warmth of the sun. Warm-blooded organisms, on the other hand, including all mammals, utilize energy released from the digestion of food to maintain a constant level of heat within their bodies. This level—a “normal” temperature—is approximately 37 degrees Celsius (98.6 degrees Fahrenheit) in humans. An internal body temperature that rises above this level is called a febrile temperature, or a fever.
If the temperature in the surrounding environment is low, warm-blooded organisms must raise their metabolic rate (a measurement, in Calories, of converted energy) accordingly to maintain a normal internal body temperature. In humans,...
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Treatment and Therapy (Magill’s Medical Guide, Sixth Edition)
The febrile response has been noted in five of the seven extant classes of vertebrates on earth (Agnatha, such as lampreys, and Chondrichthyes, such as sharks, are excluded). Scientists have determined that its function as a reaction to bacterial infection can be traced back as far as 400 million years in primitive bony fishes. The question of whether the natural phenomenon of fever actually aids in combating disease in the body, however, has not been fully resolved.
In ancient and medieval times, it was believed that fever served to “cook” and separate out one of the four essential body “humors”—blood, phlegm, yellow bile, and black bile—that had become excessively dominant. Throughout the centuries, such beliefs even caused some physicians to try to induce higher internal body temperatures as a means of treating disease. Use of modern antipyretic drugs to reduce fever remained unthinkable until the nineteenth century.
It was the German physician Carl von Liebermeister who, by the end of the nineteenth century, set some of the guidelines that are still generally observed in deciding whether antipyretic drugs should or should not be used to reduce a naturally occurring fever during illness. Liebermeister insisted that the phenomenon of fever was not one of body temperature gone “out of control” but rather a sign that the organism was regulating its own temperature. He also demonstrated that part...
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Perspective and Prospects (Magill’s Medical Guide, Sixth Edition)
Although doctors have been aware of the symptoms of fever since the beginnings of medical history, centuries passed before its importance as an indicator of disease was accepted. A certain degree of sophistication in the study of fevers became possible largely as a result of the development of the common thermometer, in a rudimentary form in the seventeenth century and then with greater technical accuracy in the eighteenth century. Systematic use of the thermometer in the eighteenth century enabled doctors to observe such phenomena as morning remission and evening peaking of fever intensity. Studies involving the recording of temperature in healthy individuals also yielded important discoveries. One such discovery was made in 1774, when use of the thermometer showed that, even in a room heated to the boiling point of water (100 degrees Celsius), healthy subjects maintained an internal body heat that was very close to the normal 37-degree level.
Medical reports as late as the end of the eighteenth century, however, indicate that even internationally recognized pioneers of science were still not close to understanding the causes of fever. The English doctor John Hunter, for example, declared himself opposed to the prevailing view that rising body heat came from the circulation of warmer blood throughout the body. Hunter suspected that the warmth was produced by an entirely different agent that was independent of the...
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For Further Information: (Magill’s Medical Guide, Sixth Edition)
Kemper, Kathi J. The Holistic Pediatrician: A Pediatrician’s Comprehensive Guide to Safe and Effective Therapies for the Twenty-five Most Common Ailments of Infants, Children, and Adolescents. Rev. ed. New York: Quill, 2002. Integrates mainstream and alternative medicine to aid parents in dealing with the most common childhood health problems such as fever, diaper rash, ear infections, and allergies.
Kluger, Matthew J. Fever: Its Biology, Evolution, and Function. Princeton, N.J.: Princeton University Press, 1979. An accessible book-length study of the phenomenon of fever. Although some parts of the discussion are more technical in nature, the general level is comprehensible.
Kluger, Matthew J., Tamas Bartfai, and Charles A. Dinarello, eds. Molecular Mechanisms of Fever. New York: New York Academy of Sciences, 1998. The authors place major emphasis on advances using molecular tools such as cytokine knockout mice, cloned cytokines, descriptions of molecular pathways for signal transduction, and heat shock proteins.
Litin, Scott C., ed. Mayo Clinic Family Health Book. 4th ed. New York: HarperResource, 2009. Perhaps the best general medical text for the layperson, this book covers the entire medical field. While the information is derived from a wide variety of highly technical sources, the articles are written to be easily understood by a general audience....
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Fever (Encyclopedia of Cancer)
Normal body temperature varies somewhat from one individual to another but displays a general range and pattern around the "normal" temperature of 98.6°F. Early morning body temperature may be as low as 97°F, and as high as 99.3°F in the afternoon hours yet still be considered normal. Higher temperatures may be observed in healthy people, but an abnormal elevation (pyrexia) is classified as hyperthermia, or fever. Fever results from a failure in the body's ability to regulate and dissipate heat. Any fever presents an unpleasant and uncomfortable state for the patient. Fever may cause the patient to experience fatigue, chills, sweats, nausea, andn some casesife-threatening conditions. When fevers occur in the elderly or the very young, the effects can be more harmful than in individuals who fall between those two age groups. The elderly may experience poor blood circulation, heart failure, an irregular heartbeat, or mental episodes. Children may lapse into fever-induced seizures. It is possible to treat fever with lukewarm sponge baths or bathing, removing excess clothing or bedding, and increasing the patient's fluid intake; however an important treatment is medication that lowers the body temperature to its normal range.
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Fever (Encyclopedia of Medicine)
A fever is any body temperature elevation over 100°F (37.8°C).
A healthy person's body temperature fluctuates between 97°F (36.1°C) and 100°F (37.8°C), with the average being 98.6°F (37°C). The body maintains stability within this range by balancing the heat produced by the metabolism with the heat lost to the environment. The "thermostat" that controls this process is located in the hypothalamus, a small structure located deep within the brain. The nervous system constantly relays information about the body's temperature to the thermostat, which in turn activates different physical responses designed to
cool or warm...
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Fever (Encyclopedia of Children's Health)
A fever is any body temperature elevation over 100.4°F (38°C).
A healthy person's body temperature fluctuates between 97°F (36.1°C) and 100°F (37.8°C), with the average being 98.6°F (37°C). The body maintains stability within this range by balancing the heat produced by the metabolism with the heat lost to the environment. The "thermostat" that controls this process is located in the hypothalamus, a small structure located deep within the brain. The nervous system constantly relays information about the body's temperature to the thermostat, which in turn activates different physical responses designed to cool or warm the body, depending on the circumstances. These responses include: decreasing or increasing the flow of blood from the body's core, where it is warmed, to the surface, where it is cooled; slowing down or speeding up the rate at which the body turns food into energy (metabolic rate); inducing shivering, which generates heat through muscle contraction; and inducing sweating, which cools the body through evaporation.
A fever occurs when the thermostat resets at a higher temperature, primarily in response to an infection. To reach the higher temperature, the body moves blood to the warmer...
(The entire section is 2010 words.)
Fever (Encyclopedia of Alternative Medicine)
A fever is a rise in body temperature to greater than 100°F (37.8°C).
A healthy person's body temperature fluctuates between 97°F (36.1°C) and 100°F (37.8°C), with the average being 98.6°F (37°C). The body maintains stability within this range by balancing the heat produced by the metabolism with the heat lost to the environment. The "thermostat" that controls this process is located in the hypothalamus, a small structure located deep within the brain. The nervous system constantly relays information about the body's temperature to the thermostat. In turn, the thermostat activates different physical responses designed to cool or warm the body, depending on the circumstances. These responses include:
- decreasing or increasing the flow of blood from the body's core, where it is warmed, to the surface, where it is cooled
- slowing down or speeding up the rate at which the body turns food into energy (metabolic rate)
- inducing shivering, which generates heat through muscle contraction
- inducing sweating, which cools the body through evaporation
A fever occurs when the body's thermostat resets at a higher temperature, which primarily happens in response to an infection. To reach the higher...
(The entire section is 1740 words.)
Fever (Encyclopedia of Nursing & Allied Health)
Fever is defined as an abnormally high body temperature or a regulated rise to a new set point of body temperature. While a body temperature above 100°F(37.8°C) is considered to be a fever by some clinicians, a significant fever is usually defined as an oral temperature of 102°F (39°C) or a rectal temperature of 103°F(39.5°C). Fever is a sign of inflammation and represents the body's response to microbial invasion or to a disease process.
Hyperthermia is defined as abnormally high body temperature caused by disruption of the body's thermoregulatory mechanisms. Hyperthermia occurs when the body's metabolic heat production or environmental heat load exceeds the normal heat loss capacity (or when normal heat loss is impaired).
The normal temperature of the human body fluctuates between 97°F (36.1°C) and 100°F (37.8°C), with the average being 98.6°F (37°C). There is a diurnal pattern of temperature variation in humans, with body temperature being lowest in the morning and highest in late afternoon. In women of childbearing age, there is a small rise in temperature following ovulation during the menstrual cycle, and during the first trimester of pregnancy.
The body's thermoregulatory mechanisms include changes in muscle tone, vascular tone, and sweat production, which serve to balance body heat produced by metabolism with heat lost to the environment. This balance is regulated by the hypothalamus, a small structure in the brain below the thalamus.The body's temperature regulation can be upset by environmental factors (external heat and humidity); by disorders or conditions that inhibit sweat production or evaporation; and by infectious diseases.
Fever occurs when the hypothalamus raises the body's temperature to a new set point. White blood cells called monocyte-macrophages release proteins called pyrogens when the cells encounter pathogenic microorganisms. The pyrogens act on the hypothalamus, causing it to reset the body's "thermostat" upward. The vessels that supply the skin with blood often narrow as the body's temperature is rising. This process, which is called vasoconstriction, reduces sweating and causes the body to retain more heat than it loses. Vasoconstriction in the skin and extremities allows the body to move blood toward its core, which increases the rate of metabolism and induces shivering. The chills that often accompany a fever are caused by this movement of blood to the body's core, which leaves the skin surface and extremities relatively cool. When the infection or disease process resolves, the hypothalamus attempts to reset the body's thermoregulation at its normal set point. The body's cooling mechanisms switch on as the blood returns to the extremities and skin surface, and sweating occurs.
Fever is an important component of the immune system's inflammatory response, though its role is not completely understood. A rise in body temperature has several effects. The pyrogens that trigger the resetting of the body's thermostat also increase the production of macrophages, which fight off invading bacteria or viruses. Higher temperatures also inhibit the growth of some bacteria, while at the same time activating the immune system. In addition, the increased heart rate that accompanies vasoconstriction also speeds the arrival of white blood cells to the sites of inflammation.
Causes and symptoms
Fever can be caused by a wide variety of diseases and disorders, including:
- infectious diseases, which may be caused by viruses, bacteria, fungi, rickettsiae, or parasites
- autoimmune disorders, including systemic lupus erythematosus, rheumatic fever, adult rheumatoid arthritis, Wegener's granulomatosis, polyarteritis nodosa, and Still's disease
- disorders of the central nervous system (CNS), including head injuries, multiple sclerosis, tumors of the brain or spinal cord, and cerebral hemorrhage
- cancers, including primary cancers of the colon, rectum, kidney, and liver, and metastatic cancers of the liver
- cardiovascular disorders, including myocardial infarction and pulmonary embolism
- reactions to such medications as methyldopa, quinidine, hydralazine, phenytoin, chlorpromazine, carbamazepine, anti-cancer drugs, and antibiotics
- endocrine disorders, including hyperthyroidism (thyroid storm) and pheochromocytoma
- gastrointestinal disorders, including alcoholic hepatitis, inflammatory bowel disease (IBD), and liver abscess
- inflammation associated with indwelling catheters, intravenous lines, and nasogastric tubes
- neuroleptic malignant syndrome, which is a rare and potentially fatal reaction to certain antipsychotic medications
Fevers may be classified as intermittent (the patient's temperature falls to normal at some point during the day); sustained (the temperature remains high); or relapsing (periods of fever are followed by several days of normal temperatures). The fever pattern may be helpful in the differential diagnosis; for example, fevers related to medication reactions are more often sustained than intermittent. A relapsing pattern suggests malaria.
The degree of temperature elevation in a fever does not necessarily correspond to the seriousness of the illness. In general, children with fevers run higher temperatures than adults, while elderly persons and newborns may have less marked fevers.
The differential diagnosis of fever is complicated by the variety of possible causes. In most cases, the patient's historyncluding a medication history and history of exposure to infectious diseasesital signs, a complete blood count, and blood cultures will help to narrow the number of possible causes. In fevers of unknown origin (FUOs), however, the physician may need to schedule a chest x-ray or ultrasound and CT imaging.
Fevers of unknown origin (FUOs)
The origin of some fevers is difficult to determine. The term "fever of unknown origin" (FUO) has been applied to cases of fever in which the patient's temperature remains over 101°F (38.3°C) for three weeks and in which the diagnosis is not apparent after seven or more days of studies. The most common cause of FUOs is an infectious disease of some kind, although many cancers present initially as FUOs. About 15% of FUOs never receive a definite diagnosis.
A variety of different devices are available to register body temperature, including the traditional glass thermometers used for oral or rectal temperature readings. More recently, sophisticated electronic devices have been introduced that register body temperature as a digital readout. For younger children and infants, there are fore-head meter strips and pacifiers with temperature-sensitive readouts.
Most fevers are caused by common infections, are short-lived, and do not require symptomatic treatment. The patient's comfort, however, may be improved by measures to remove body heat, antipyretic medications, and fluid replacement. Measures to remove body heat include alcohol or cold sponges; ice bags; and ice baths. The most common antipyretic medications are aspirin or acetaminophen, 35050 mg every four hours. Children or adolescents with influenza-like symptoms should not be given aspirin without consulting a physician because of the possibility of developing Reye's syndrome, a rare disorder characterized by vomiting and liver dysfunction.
Fluid replacement is an important part of fever treatment. Extra fluid is required to prevent electrolyte imbalance as well as to replace fluid lost through perspiration.
Body temperature over 105.8°F (41°C) in an adult is a medical emergency and requires immediate treatment.
The following indications in specific patient groups may require emergency treatment:
- newborns (three months or younger) with fever of 100.5°F (38°C) or higher
- infants or children with fever of 103°F (39.4°C) or higher
- adults with fever of 101°F or higher lasting longer than three days; or a temperature of 100.5°F lasting longer than three weeks without other symptoms
A very high fever in a small child can trigger febrile seizures, and therefore requires immediate treatment. A fever accompanied by a stiff neck, severe headache, throat swelling, and changes in mental status may indicate the presence of meningitis or another serious infection, and should be brought to the immediate attention of a physician. High fever does not always produce sweating or diaphoretic symptoms, which indicates weakness in the body's defenses against severe disease.
Most fevers caused by infection end as soon as the immune system rids the body of the pathogen and do not produce any lasting effects. Exceptions include fevers associated with meningitis, typhoid, or scarlet fever. High fevers can produce major disturbances of the body's metabolism and alter the body's responses to medications. In addition, a high fever during the first trimester of pregnancy increases the risk of such birth defects as anencephaly (absence of a portion of the skull and brain).
The prognosis for fevers associated with such chronic conditions as autoimmune disorders depends on the stage of the disease and its management.
Health care team roles
Nurses assess and record the fever patient's signs and symptoms. Nurses as well as physicians can obtain relevant information from the patient's medical history. Home health care and visiting nurses may also help to educate patients about at-home treatment of fevers. In some cases, home care nurses may counsel patients and caregivers over the phone, advising when the condition warrants in-person medical attention.
Since most fevers are caused by infectious agents, careful attention to proper methods of food handling, hand washing, and similar public health measures is an important form of prevention. Fevers related to medication reactions can sometimes be prevented by substitution of drugs that are less likely to produce such reactions. Fevers related to indwelling catheters and similar devices may be avoided by removing them as soon as they are no longer required.
Hyperthermia related to environmental conditions may be prevented by proper attention to climatic conditions, adequate fluid and electrolyte intake, and acclimatization to hot environments. Educating the public about the early signs of heat disorders is another important preventive measure.
Antipyretic drug that lowers body temperature, such as aspirin or acetaminophen.
Autoimmune disease disorder in which the immune system attacks the body's own cells.
Febrile seizureonvulsions brought on by high body temperature and inflammation of the brain or brain covering.
Hyperthermiabnormally high body temperature that occurs when the body's metabolic heat production or environmental heat load exceeds the normal heat loss capacity (or when heat loss is impaired). Heat stroke is an example of hyperthermia.
Hypothalamus region in the posterior section of the forebrain that regulates body temperature, sleep cycles, and the activity of the pituitary gland.
Intermittent fever pattern marked by the patient's temperature returning to normal at some point during the day.
Macrophage type of large white blood cell that helps the body fight off pathogenic microorganisms by ingesting them.
Malignant hyperthermia rare inherited condition in which a person develops a very high fever when given general anesthetics or muscle relaxants in preparation for surgery.
Pyrogen substance that produces a rise in body temperature. Bacterial toxins are one type of pyrogen.
Relapsing fever pattern in which periods of fever alternate with several days of normal temperatures.
Reye's syndrome rare disorder that occurs primarily in children recovering from a viral illness and associated with aspirin usage. It is characterized by vomiting, swelling of the brain, and liver dysfunction.
Vasoconstrictionarrowing of the blood vessels, which serves to conserve body heat and maintain or raise blood pressure.
Gelfand, Jeffrey, et al. "Fever, Including Fever of Unknown Origin." Harrison's Principles of Internal Medicine, edited by Kurt Isselbacher, et al. New York: McGraw-Hill, 1997.
Haist, Steven A., MD, John B. Robbins, MD, and Leonard G. Gomella, MD. "Fever." Internal Medicine On Call, 2nd ed. Stamford, CT: Appleton & Lange, 1997.
"Respiratory Viral Diseases." Chapter 162 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.
Fever. MayoClinic.com. September 11, 2000. <<a href="http://www.mayoclinic.com/home?id=DS00077">http://www.mayoclinic.com/home?id=DS00077>. (accessed June 18, 2001).