Fever 

Definition

A fever is any body temperature elevation over 100 °F (37.8 °C).

Description

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 interior, increases the metabolic rate, and induces shivering. The "chills" that often accompany a fever are caused by the movement of blood to the body's core, leaving the surface and extremities cold. Once the higher temperature is achieved, the shivering and chills stop. When the infection has been overcome or drugs such as aspirin or acetaminophen (Tylenol) have been taken, the thermostat resets to normal and the body's cooling mechanisms switch on: the blood moves to the surface and sweating occurs.Fever is an important component of the immune response, though its role is not completely understood. Physicians believe that an elevated body temperature has several effects. The immune system chemicals that react with the fever-inducing agent and trigger the resetting of the thermostat also increase the production of cells that

fight off the invading bacteria or viruses. Higher temperatures also inhibit the growth of some bacteria, while at the same time speeding up the chemical reactions that help the body's cells repair themselves. In addition, the increased heart rate that may accompany the changes in blood circulation also speeds the arrival of white blood cells to the sites of infection.

Causes and symptoms

Fevers are primarily caused by viral or bacterial infections, such as pneumonia or influenza. However, other conditions can induce a fever, including allergic reactions; autoimmune diseases; trauma, such as breaking a bone; cancer; excessive exposure to the sun; intense exercise; hormonal imbalances; certain drugs; and damage to the hypothalamus. When an infection occurs, fever-inducing agents called pyrogens are released, either by the body's immune system or by the invading cells themselves, that trigger the resetting of the thermostat. In other circumstances, the immune system may overreact (allergic reactions) or become damaged (autoimmune diseases), causing the uncontrolled release of pyrogens. A stroke or tumor can damage the hypothalamus, causing the body's thermostat to malfunction. Excessive exposure to the sun or intensely exercising in hot weather can result in heat stroke, a condition in which the body's cooling mechanisms fail. Malignant hyperthermia is a rare, inherited condition in which a person develops a very high fever when given certain anesthetics or muscle relaxants in preparation for surgery.How long a fever lasts and how high it may go depends on several factors, including its cause, the age of the patient, and his or her overall health. Most fevers caused by infections are acute, appearing suddenly and then dissipating as the immune system defeats the infectious agent. An infectious fever may also rise and fall throughout the day, reaching its peek in the late afternoon or early evening. A low-grade fever that lasts for several weeks is associated with autoimmune diseases such as lupus or with some cancers, particularly leukemia and lymphoma.

A dramatic rise in body temperature often includes the following symptoms: A. Loss of fluid results in dehydration. B. The hypothalamic set-point is increased, raising metabolism. C. Blood vessels in skin dilate. D. Sweat glands produce excess perspiration. E. Increased pulse rate. F. Increased hypothalmic set-point may introduce chills and shivering to promote heat production from muscles. G. Skin becomes more heat-sensitive.

(Illustration by Electronic Illustrators Group.)

Diagnosis

A fever is usually diagnosed using a thermometer. A variety of different thermometers are available, including traditional glass and mercury ones used for oral or rectal temperature readings and more sophisticated electronic ones that can be inserted in the ear to quickly register the body's temperature. For adults and older children, temperature readings are usually taken orally. Younger children who cannot or will not hold a thermometer in their mouths can have their temperature taken by placing an oral thermometer under their armpit. Infants generally have their temperature taken rectally using a rectal thermometer.As important as registering a patient's temperature is determining the underlying cause of the fever. The presence or absence of accompanying symptoms, a patient's medical history, and

information about what he or she may have ingested, any recent trips taken, or possible exposures to illness help the physician make a diagnosis. Blood tests can aid in identifying an infectious agent by detecting the presence of antibodies against it or providing samples for growth of the organism in a culture. Blood tests can also provide the doctor with white blood cell counts. Ultrasound tests, magnetic resonance imaging (MRI) tests, or computed tomography (CT) scans may be ordered if the doctor cannot readily determine the cause of a fever.

Treatment

Physicians agree that the most effective treatment for a fever is to address its underlying cause, such as through the administration of antibiotics. Also, because a fever helps the immune system fight infection, it usually should be allowed to run its course. Drugs to lower fever (antipyretics) can be given if a patient (particularly a child) is uncomfortable. These include aspirin, acetaminophen (Tylenol), and ibuprofin (Advil). Aspirin, however, should not be given to a child or adolescent with a fever since this drug has been linked to an increased risk of Reye's syndrome. Bathing a patient in cool water can also help alleviate a high fever.A fever requires emergency treatment under the following circumstances:

newborn (three months or younger) with a fever over 100.5 °F (38 °C)

infant or child with a fever over 103 °F (39.4 °C) fever accompanied by severe headache, neck stiffness,

mental confusion, or severe swelling of the throat

A very high fever in a small child can trigger seizures (febrile seizures) and therefore should be treated immediately. A fever accompanied by the above symptoms can indicate the presence of a serious infection, such as meningitis, and should be brought to the immediate attention of a physician.

Prognosis

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. The prognosis for fevers associated with more chronic

conditions, such as autoimmune disease, depends upon the overall outcome of the disorder.

Resources

Books

Gelfand, Jeffrey. "Fever, Including Fever of Unknown Origin." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1997.

Key terms

Antipyretic — A drug that lowers fever, like aspirin or acetaminophen.Autoimmune disease — Condition in which a person's immune system attacks the body's own cells, causing tissue destruction.Febrile seizure — Convulsions brought on by fever.Malignant hyperthermia — A rare, inherited condition in which a person develops a very high fever when given certain anesthetics or muscle relaxants in preparation for surgery.Meningitis — A potentially fatal inflammation of the thin membrane covering the brain and spinal cord.Metabolism — The chemical process by which the body turns food into energy, which can be given off as heat.Pyrogen — A chemical circulating in the blood that causes a rise in body temperature.Reye's syndrome — A disorder principally affecting the liver and brain, marked by the rapid development of life-threatening neurological symptoms.Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

fever

/fe·ver/ (fe´ver) 1. pyrexia; elevation of body temperature above the normal (37°C).2. any disease characterized by elevation of body temperature.

blackwater fever  a dangerous complication of falciparum malaria, with passage of dark red to black urine, severe toxicity, and high mortality.boutonneuse fever  a tickborne disease endemic in the Mediterranean area, Crimea, Africa, and India, due to infection with Rickettsia conorii, with chills, fever, primary skin lesion (tache noire), and rash appearing on the second to fourth day.cat-scratch fever  see under disease. central fever  sustained fever resulting from damage to the thermoregulatory centers of the hypothalamus.childbed fever  puerperal septicemia.Colorado tick fever  a tickborne, nonexanthematous, febrile, viral disease caused by an arenavirus and seen in the Rocky Mountain area of the United States.continued fever  one that varies only slightly in 24 hours.Crimean-Congo hemorrhagic fever  a hemorrhagic fever caused by the Crimean-Congo hemorrhagic fever virus, transmitted by ticks and by contact with blood, secretions, or fluids from infected animals or humans; it occurs in the Crimea, Central Asia, and regions of Africa.drug fever  febrile reaction to a therapeutic agent, such as a vaccine, antineoplastic, or antibiotic.elephantoid fever  a recurrent acute febrile condition occurring with filariasis; it may be associated with elephantiasis or lymphangitis.enteric fever  any of a group of febrile illnesses associated with enteric symptoms caused by salmonellae, especially typhoid fever and paratyphoid fever.epidemic hemorrhagic fever  an acute infectious disease characterized by fever, purpura, peripheral vascular collapse, and acute renal failure, caused by viruses of the genus Hantavirus, thought to be transmitted to humans by contact with saliva and excreta of infected rodents.familial Mediterranean fever  a hereditary disease usually seen in Armenians and Sephardic Jews, with short recurrent attacks of fever, pain in the abdomen, chest, or joints, and erythema like that of erysipelas; it may be complicated by amyloidosis.Haverhill fever  the bacillary form of rat-bite fever, due to Streptobacillus moniliformis, and transmitted through contaminated raw milk and its products.hay fever  a seasonal form of allergic rhinitis, with acute conjunctivitis, lacrimation, itching, swelling of the nasal mucosa, nasal catarrh, and attacks of sneezing, an anaphylactic or allergic reaction excited by a specific allergen (such as pollen).

hemorrhagic fevers  a group of diverse, severe viral infections seen around the world but mainly in the tropics, usually transmitted to humans by arthropod bites or contact with virus-infected rodents; they all have certain common features, including fever, hemorrhagic manifestations, thrombocytopenia, shock, and neurologic disturbances.humidifier fever  malaise, fever, cough, and myalgia caused by inhalation of air that has been passed through humidifiers, dehumidifiers, or air conditioners contaminated by fungi, amebas, or thermophilic actinomycetes.intermittent fever  an attack of malaria or other fever, with recurring fever episodes separated by times of normal temperature.Katayama fever  fever associated with severe schistosomal infections, accompanied by hepatosplenomegaly and by eosinophilia.Lassa fever  a highly fatal, acute, febrile disease seen in West Africa, caused by a virulent arenavirus and characterized by increasing prostration, sore throat, ulcerations of the mouth or throat, rash, and general aching.metal fume fever  a disease of welders and others working with volatilized metals, marked by sudden thirst, metallic taste in the mouth, high fever with chills, sweating, and leukocytosis.mud fever  a type of leptospirosis seen in workers in flooded fields and swamps in Germany and Russia.nonseasonal hay fever , hay fever, perennial nonseasonal allergic rhinitis.Oroya fever  see Carrión's disease. paratyphoid fever  paratyphoid.parenteric fever  a disease clinically resembling typhoid fever and paratyphoid, but not caused by Salmonella. parrot fever  psittacosis.pharyngoconjunctival fever  an epidemic disease due to an adenovirus, seen mainly in school children, with fever, pharyngitis, conjunctivitis, rhinitis, and enlarged cervical lymph nodes.phlebotomus fever  a febrile viral disease of short duration, transmitted by the sandfly Phlebotomus papatasi, with dengue-like symptoms, seen in Mediterranean and Middle Eastern countries.Pontiac fever  a self-limited disease marked by fever, cough, muscle aches, chills, headache, chest pain, confusion, and pleuritis, caused by a strain of Legionella pneumophila. pretibial fever  an infection due to a serovar of Leptospira interrogans, marked by a rash on the pretibial region, with lumbar and postorbital pain, malaise, coryza, and fever.

puerperal fever  septicemia accompanied by fever, in which the focus of infection is a lesion of the mucous membrane of the parturient canal due to trauma during childbirth; usually due to a streptococcus.Q fever  a febrile rickettsial infection, usually respiratory, first described in Australia, caused by Coxiella burnetii. rat-bite fever  either of two clinically similar acute infectious diseases, usually transmitted through a rat bite, one form (bacillary) of which is caused by Streptobacillus moniliformis and the other form (spirillary) by Spirillum minor. recurrent fever  1. relapsing f.2. recurrent paroxysmal fever occurring in various diseases, such as malaria.relapsing fever  any of a group of infectious diseases due to various species of Borrelia, marked by alternating periods of fever and apyrexia, each lasting from five to seven days.remittent fever  one that shows significant variations in 24 hours but without return to normal temperature.rheumatic fever  a febrile disease occurring as a sequela to Group A hemolytic streptococcal infections, characterized by multiple focal inflammatory lesions of connective tissue structures, especially of the heart, blood vessels, and joints, and by Aschoff bodies in the myocardium and skin.Rift Valley fever  a zoonotic febrile disease with dengue-like symptoms, due to an arbovirus, transmitted to humans by mosquitoes or by contact with diseased animals; first observed in the Rift Valley, Kenya.Rocky Mountain spotted fever  infection with Rickettsia rickettsii, transmitted by ticks, marked by fever, muscle pain, and weakness followed by a macular petechial eruption that begins on the hands and feet and spreads to the trunk and face, with other symptoms in the central nervous system and elsewhere.rose fever  a form of hay fever caused by grass pollens released while roses or other flowers are blooming.scarlet fever  an acute disease caused by Group A β-hemolytic streptococci, marked by pharyngotonsillitis and a skin rash caused by an erythrogenic toxin produced by the organism; the rash is a diffuse, bright red erythema, and desquamation of the skin begins as fine scaling with eventual peeling of the palms and soles.Sennetsu fever  a febrile disease seen in Japan and Malaysia and caused by Ehrlichia sennetsu, characterized by headache, nausea, lymphocytosis, and lymphadenopathy.septic fever  fever due to septicemia.

South African tickbite fever  boutonneuse f.trench fever  a louse-borne rickettsial disease due to Bartonella quintana, transmitted by the body louse, Pediculus humanus corporis, and characterized by intermittent fever, generalized aches and pains, particularly severe in the shins, chills, sweating, vertigo, malaise, typhus-like rash, and multiple relapses.typhoid fever  infection by Salmonella typhi chiefly involving the lymphoid follicles of the ileum, with chills, fever, headache, cough, prostration, abdominal distention, splenomegaly, and a maculopapular rash; perforation of the bowel may occur in untreated cases.fever of unknown origin  (FUO) a febrile illness of at least three weeks' duration (some authorities permit a shorter duration), with a temperature of at least 38.3°C on at least three occasions and failure to establish a diagnosis in spite of intensive inpatient or outpatient evaluation (three outpatient visits or three days' hospitalization).West Nile fever  see under encephalitis. yellow fever  an acute, infectious, mosquito-borne viral disease, endemic primarily in tropical South America and Africa, marked by fever, jaundice due to necrosis of the liver, and albuminuria.Dorland's Medical Dictionary for Health Consumers. © 2007 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

fe·ver

(fē′vər)n.1. Body temperature above the normal of 98.6°F (37°C). Also called pyrexia.2. Any of various diseases in which there is an elevation of the body temperature above normal.The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

fever

Etymology: L, febris an elevation of body temperature above the normal circadian range as a result of an increase in the body's core temperature. Fever is a temperature above 37.2° C (98.9° F) in the morning or above 37.7°

C (99.9° F) in the evening. Fever results from an imbalance between the elimination and the production of heat. Exercise, anxiety, and dehydration may increase the temperature of healthy people. Infection, neurologic disease, malignancy, pernicious anemia, thromboembolic disease, paroxysmal tachycardia, congestive heart failure, crushing injury, severe trauma, and many drugs may cause fever. No single theory explains the mechanism whereby the temperature is increased. Fever has no recognized function in conditions other than infection. It increases metabolic activity by 7% per degree Celsius, requiring a greater intake of food. Convulsions may occur in children whose fevers tend to rise abruptly, and delirium is seen with high fevers in adults and in children. Very high temperatures, as in heatstroke, may be fatal. The course of a fever varies with the cause, the condition of the patient, and the treatment given. The onset may be abrupt or gradual, and the period of maximum elevation, called the stadium or fastigium, may last for a few days or up to 3 weeks. The fever may resolve suddenly, by crisis, or gradually, by lysis. Certain diseases and conditions are associated with fevers that begin, rise, and fall in such characteristic curves that diagnosis may be made by studying a graphic record of the course of the fever. Kinds of hyperthermia include habitual fever , intermittent fever, and relapsing fever. Also called febrile response. See also fever treatment, hyperpyrexia, quartan malaria, remittent fever, septic fever, tertian malaria. Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.

fever

 [fe´ver] 1. an abnormally high body temperature; called also pyrexia. adj., adj fe´brile, fe´verish.2. any disease characterized by marked increase of body temperature. For specific diseases, see the eponymic or descriptive name, such as ROCKY MOUNTAIN SPOTTED FEVER or TYPHOID FEVER . Other conditions involving elevated body temperature include HEAT EXHAUSTION and HEAT STROKE .

Normal body temperature when the body is at rest is 37°C (98.6°F). This is an average or mean body temperature that varies from person to person and from hour to hour in an individual. The route by which a body temperature is measured affects the reading. The normal oral temperature ranges from 36° to 37.5°C (96.8° to

99.5°F). If the temperature is measured rectally, the norm would be 0.5°C (1°F) higher. An axillary temperature would be 0.5°C (1°F) lower. Because of these differences, the number should always be followed by the route by which the temperature was taken when the reading is recorded.

Factors that can cause a temporary elevation in body temperature include age, physical activity, emotional stress, and ovulation. If a person has a consistently elevated temperature, fever is said to exist. A low-grade fever is marked by temperatures between 37.5° and 38.2°C (99.5° and 101°F) when taken orally. A high-grade fever is present when the oral temperature is above 38.2°C (101°F).

Types of fever include continued or continuous fever, one lasting more than 24 hours without significant variation or any return to normal body temperature; intermittent fever, in which at least once during a 24-hour period the fever spikes are separated by a return to normal body temperature; remittent fever, in which elevated body temperature shows fluctuations each day but never returns to normal; and recurrent (or relapsing) fever, in which periods of fever and normal body temperature alternate and last about 5 to 7 days each.

The regulation of body temperature is under the control of the HYPOTHALAMUS. Thermolysis, or dissipation of body heat, is regulated by the anterior hypothalamus in conjunction with the parasympathetic nervous system. The overall effect of heat loss is accomplished by vasodilation of the peripheral blood vessels, increased sweating, and decreased metabolic and muscular activities. The production and conservation of body heat, or thermogenesis, is regulated by the posterior hypothalamus in conjunction with the sympathetic nervous system. The mechanisms by which body heat is produced and conserved are in opposition to those that increase heat loss; that is, by constriction of cutaneous blood vessels, decreased sweat gland activity, and increased metabolic and muscular activities.

Fever develops when there is some disturbance in the homeostatic mechanisms by which the hypothalamus maintains a balance between heat production and peripheral heat loss. Although dehydration, cerebral hemorrhage, heat stroke, thyroxine, and certain other drugs can cause an elevated body temperature or hyperthermia, fever, in the precise sense of the term, occurs as a result of inflammation or infection, or both. During the infectious

and inflammatory processes certain substances called pyrogens are produced within the body. These endogenous pyrogens are the result of inflammatory reactions, such as those that occur in tissue damage, cell necrosis, rejection of transplanted tissues, malignancy, and antigen-antibody reactions. Exogenous pyrogens are introduced into the body when it is invaded by bacteria, viruses, fungi, and other kinds of infectious organisms.

Endogenous pyrogens act directly on the hypothalamus, affecting its thermostatic functions by “resetting” it to a higher temperature. When this happens, all of the physiologic activities concerned with heat production and conservation operate to maintain body temperature at a higher setpoint. The symptoms of chill and shivering are the result of increased muscular activity, which is an attempt by the body to raise its temperature to the higher setting. This increased muscular activity is accompanied by an elevation of the metabolic rate, which in turn increases the demand for nutrients and oxygen. Outward signs of these internal activities include a higher pulse rate, increased respirations, and thirst caused by the loss of extracellular water via the lungs. The pulse rate increases at the rate of about eight to ten beats per minute for each degree of temperature rise.

Once the body temperature reaches the setpoint of the hypothalamic thermostat, the mechanisms of heat production and heat loss keep it at a fairly constant level and the fever persists. This is sometimes called the second stage of fever. If it continues, fluid and electrolyte losses become more severe and there is evidence of cellular dehydration. During this stage DELIRIUM in older persons and CONVULSIONS in infants and children can occur. Febrile convulsions in children are believed to be closely related to cerebral damage that becomes evident as afebrile convulsions later in life.

Prolonged fever eventually brings about tissue destruction owing to the catabolism of body proteins. Because of this the patient experiences muscle aches and weakness, malaise, and the excretion of albumin in the urine. Anorexia also is present. If the body does not receive a sufficient supply of energy from dietary intake to meet its metabolic needs, it catabolizes its own fat and protein. The patient then rapidly loses weight and can develop KETOSIS and metabolic ACIDOSIS .

The period during which a fever abates is called the period of defervescence. It may occur rapidly and dramatically, as the

temperature falls from peak to normal in a matter of hours. This is called the crisis, that is, the critical point at which the fever is broken. A more gradual resetting of the thermostat and slow decline of the fever is called resolution of the fever by lysis.TREATMENT. It is not always necessary to reduce fever and in many cases it may be best not to treat it, at least until its cause is determined. The fever pattern can provide diagnostic information and is not necessarily harmful unless it is extremely high or the patient has cardiac or respiratory disease and cannot tolerate the additional tachycardia and dyspnea that may accompany fever. An elevated body temperature can inhibit bacterial replication and the action of viruses, spirochetes, and other pathogenic microorganisms.

If it is decided that treatment is necessary, there are two major goals: to identify the cause and to provide symptomatic relief. Antipyretic drugs such as aspirin and acetaminophen (Tylenol) are generally safe and effective. However, acetaminophen is preferred in children and when the patient has gastrointestinal sensitivity, allergy to aspirin, or a clotting disorder or is suspected of having Reye's syndrome.

Fluids and electrolytes are replaced orally or intravenously as indicated by laboratory tests and signs of dehydration. Frequent, small feedings of high-calorie, high-protein foods are recommended to combat fatigue and debility caused by the increased metabolic rate. The selection of oral liquids and foods should be based on the patient's preferences. Vitamin supplements may be prescribed in prolonged, low-grade fevers.PATIENT CARE. The patient with acute hyperpyrexia or hyperthermia will require extreme measures to lower the body temperature as quickly and safely as possible in order to prevent brain damage. Victims of heat stroke should be cooled rapidly. In order to keep the temperature at a tolerable level until the thermostat is reset, a cooling blanket or hypothermia mattress may be used. Care must be taken to maintain the integrity of the skin and avoid sudden and extreme hypothermia when such a device is used. Other measures include sponging parts of the body with cool water to increase heat loss through evaporation of moisture. The part being sponged should be left exposed to the air until it is almost dry, and then should be lightly covered while another part is being sponged. A cold compress on the forehead helps to reduce the fever and relieve headache and delirium. An alternative to sponging and a cool bath is the application of ice packs to specific parts of the body, such as

the abdomen, groin, axillae, and spine. Fanning can also be effective, especially if the patient's torso is covered with a sheet saturated with water.

Chills are uncomfortable and sometimes frightening to the patient. When the patient complains of feeling chilled or cold, some form of external warmth should be provided. An extra blanket is helpful as is a hot water bottle filled with warm, not hot, water. As the body temperature declines the difference between body temperature and environmental temperature will decrease and the patient will begin to feel warmer. During the second stage of fever the patient may complain of feeling hot; the skin feels warm to the touch and the face is flushed. These symptoms are the result of vasodilation of surface blood vessels, an attempt by the body to prevent further escalation of the body temperature.fever of unknown origin (FUO) a febrile illness of at least three weeks' duration with a temperature of at least 38.3°C on at least three occasions and failure to establish a diagnosis in spite of intensive inpatient or outpatient evaluation (three outpatient visits or three days' hospitalization). The duration of febrile illness needed to establish a diagnosis of FUO varies among authorities and is sometimes given as shorter than three weeks.

Classic fever of unknown origin, as defined by the preceding criteria, is distinguished from neutropenic and nosocomial FUO, as well as that associated with human immunodeficiency virus infection. In the neutropenic form, fever is accompanied by a neutrophil level that is lower than 500/mm3 or is expected to fall below that level within one or two days. The nosocomial form is a fever that occurs on several occasions in a hospitalized patient in whom neither fever nor infection was present on admission. In HIV-associated FUO, fever occurs in a person with human immunodeficiency virus infection on several occasions over a period of four weeks of outpatient care or three days of hospitalization. In all three of these forms of FUO, the cause of the fever cannot be determined after three days of investigation, including two days of incubation of cultures.Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

fever,

n condition characterized by a rise in body temperature. Most fevers are mild and can be treated at home, but if they last more than two days, if the temperature rises to over 102.2° F, or if body temperature suddenly rises to 102.2° F within four hours, it is considered dangerous, and professional treatment should be sought immediately.Jonas: Mosby's Dictionary of Complementary and Alternative Medicine. (c) 2005, Elsevier.

fever (pyrexia)

(pīrek´sēə), n an elevation of the body temperature.hand-foot-and-mouth fever, aphthous,n See disease.fever, cat-scratch,n See disease, cat-scratch.fever, hay,n rhinitis and conjunctivitis resulting from allergy; frequently caused by allergy to pollens.fever, of unknown origin,n the persistent elevation of body temperature without an identifiable cause.fever, rheumaticn a severe, apparently infectious disease produced by hemolytic streptococci organisms or associated with their presence in the body; characterized by upper respiratory tract inflammation, cervical lymphadenopathy and lymphadenitis, polyarthritis, cardiac involvement, and subcutaneous nodules. The disease may be produced by an autoantibody reaction.fever, scarlet (scarlatina),n an acute disease caused by a specific type of Streptococcus organism and characterized by a rash and strawberry tongue.fever, uveoparotid (Heerfordt's syndrome, uveoparotitis)n 1. a disease characterized by inflammation of the parotid gland and of the uveal regions of the eye. 2. the firm, nodular enlargement of the parotid glands, uveitis, and cutaneous lesions may be present. Considered to be a form of sarcoidosis. 3. a syndrome consisting of sarcoidosis affecting the parotid glands, inflammation of the lacrimal glands, and inflammation of the uveal tract of the eye.

Mosby's Dental Dictionary, 2nd edition. © 2008 Elsevier, Inc. All rights reserved.

fever

1. an abnormally high body temperature; pyrexia. See also hyperthermia.2. any disease characterized by marked increase of body temperature. See body temperature.For diseases characterized by fever, see the eponymic or descriptive name: e.g. african swine, bovine petechial, canicola, cat-scratch disease, desert, ephemeral, equine intestinal ehrlichiosis, classical swine fever (hog cholera) , malignant catarrhal fever, malta, mediterranean coast, q, rift valley, rocky mountain spotted, Russian spring-summer encephalitis, tickborne, tularemia, undulant. milk fever is not accompanied by pyrexia.

aseptic feverfever associated with aseptic wounds, presumably due to the disintegration of leukocytes or to the absorption of avascular or traumatized tissue.central feversustained fever resulting from damage to the thermoregulatory centers of the hypothalamus.chemical feverfever caused by the intake of a sterile substance, e.g. the injection of a foreign protein, the administration of dinitrophenols.continued fever, continuous feverpersistently elevated body temperature, showing no or little variation and never falling to normal during any 24-hour period.intermittent feveran attack of fever, with recurring paroxysms of elevated temperature separated by intervals during which the temperature is normal.remittent feverelevated body temperature showing fluctuation each day, but never falling to normal.septic feversee septic fever.Shar Pei feversee familial renal amyloidosis.fever of unknown origin (FUO)

a recognized clinical syndrome of persistently (>2 weeks) elevated body temperature (>104°F) and without other signs. Causes include infections, neoplasia, immune-mediated diseases, and drug reactions.Saunders Comprehensive Veterinary Dictionary, 3 ed. © 2007 Elsevier, Inc. All rights reserved

fever

Internal medicine A body temperature of ≥ 37.2ºC/99.0ºF in early morning or ≥ 37.8ºC/100.0ºF in the evening that is a complex and coordinated adaptive response, which is part of the reaction to an immune challenge; this response is stereotyped, and largely independent of a causitive agent; as with other integrated responses–eg, regulation of energy metabolism, BP and volume, and reproduction, fever depends on humoral cues and is orchestrated by the hypothalamus, which coordinates autonomic, behavioral, endocrine, and metabolic responses– when corporal temperature is raised by endogenous pyrogen, T cell production ↑ 20-fold; endogenous pyrogen also shifts iron–needed by bacteria away from plasma; hyperthermia–up to 40ºC may trigger CA regression. See 'Animal House fever' Argentine hemorrhagic fever, Blackwater fever, Blue fever, Breakbone fever, Bolivian hemorrhagic fever, Bullis fever, Cabin fever, Cat-bite fever, Coley's toxin, Colorado tick fever, Congo-Crimean hemorrhagic fever, Cotton fever, Dehydration fever, Dengue hemorrhagic fever, Epidemic louse-borne typhus fever, Familial hibernian fever, Familial Mediterranean fever, Filarial fever, Fort Bragg fever, Haverhill fever, Hay fever, Hectic-septic fever, Hypothalamic fever, Izumi fever, Korean hemorrhagic fever, Lassa fever, Malta fever, Mediterranean fever, Metal fume fever, Omsk hemorrhagic fever, O'nyong-nyong fever, Polymer fume fever, Pontiac fever, Potamic fever, Q fever, Quartan fever, Quintan fever, Rat-bite fever, Relapsing fever, Rheumatic fever, Rift Valley fever, Rocky Mountain spotted fever, Sandfly fever, Scarlet fever, Seven-day fever, Simian hemorrhagic fever, Spring fever, Swamp fever, Tertian fever, Thirteen day fever, Three day fever, Trench fever, Valley fever, West Nile fever, Yellow fever. McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

fe·ver

(fē'vĕr), A complex physiologic response to disease mediated by pyrogenic cytokines and characterized by a rise in core temperature, generation of acute phase reactants, and activation of immune systems.Synonym(s): febris, pyrexia[A.S. fefer]

fe·ver

pyrexiophobia.Farlex Partner Medical Dictionary © Farlex 2012

fe·ver

(fē'vĕr) A complex physiologic response to disease mediated by pyrogenic cytokines and characterized by a significant rise in core temperature, generation of acute phase reactants, and activation of immunologic systems. Synonym(s): pyrexia. [A.S. fefer]Medical Dictionary for the Health Professions and Nursing © Farlex 2012

fe·ver

(fē'vĕr) A complex physiologic response to disease mediated by pyrogenic cytokines and characterized by a rise in core temperature, generation of acute phase reactants, and activation of immune systems. Synonym(s): pyrexia. [A.S. fefer]Medical Dictionary for the Dental Professions © Farlex 2012

fever

pyrexia: body temperature >37°C (>98.4°F)

Illustrated Dictionary of Podiatry and Foot Science by Jean Mooney © 2009 Elsevier Limited. All rights reserved.

Patient discussion about Fever

Q. High Fever - is it dangerous? high fever over a long period can be dangerous. on the other hand it shows also that your body is working like Superman...

A. the heart surgeon knows, that if he touchs during a heart-operation this sparkle of 96°C, the patient will die. exitus for sure! the problem for the heart surgeon is, that he don't know why it is so. this is the big problem you can have with a doctor who don't know about such things. if you like to know more about this sparkle and why the patient dies, write me a mail and i will share with you a link to read about it. ask me if you don't understand me for what i try to teach you. FEVER is a healing-system nature gave us. Let it work naturally. don't make a tonsillectomy just because some do or because it is a fashion. think first about it. your tonsils have functions and we need them. they are not just decoration. my parents forced me to make a tonsillectomy because they were told to do so because i had many otitis. i would never do it to my kids. i have since 30 years from time to time pain there and i loose some blood. it hurts terribly when it is acute.

Q. What Causes Cough With Fever? Often during winter I become sick with fever and on going cough. What causes it?

A. Cough with fever can be a first sign to many respiratory tract infections with viruses or bacterias, starting from simple ones as the common cold (or "flu") up to more serious conditions such as pneumonia, that requires medical care and medications.

Q. What Treats Cough With Fever? I have the flu and so my entire body hurts, and I can't stop coughing. What type of medications can I buy over-the-counter to help me feel better?

A. Simple analgesics are good for lowering fever and easing pain. As for the cough, there is a question whether or not cough suppressants are actually recommended. http://www.5min.com/Video/Do-Cough-Syrups-Work-5602143More discussions about Fever

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FeverFrom Wikipedia, the free encyclopediaThis article is about the medical condition. For other uses, see Fever (disambiguation).

Fever

An analog medical thermometer showing a temperature of 38.8 °C or 101.8 °F

ICD-10 R50ICD-9 780.6

DiseasesDB 18924MedlinePlus 003090eMedicine med/785

MeSH D005334

Fever, also known as pyrexia and febrile response,[1] is defined as having a temperature above the normal range due to an increase in the body's temperature set-point.[2][3] There is not a single agreed upon upper limit for normal temperature with sources using values between 37.5 and 38.3 °C (99.5 and 100.9 °F).[1][4] The increase in set-point triggers increased muscle contraction and causes a feeling of cold.[5] This results in greater heat production and efforts to conserve heat.[6] When the set-point temperature returns to normal a person feels hot, becomes flushed, and may begin to sweat.[6] Rarely a fever may trigger a febrile seizure. This is more common in

young children.[7] Fevers do not typically go higher than 41 to 42 °C (105.8 to 107.6 °F).[3]

A fever can be caused by many medical conditions ranging from the not serious to potentially serious. This includes viral, bacterial and parasitic infections such as the common cold, urinary tract infections, meningitis, malaria and appendicitis among others. Non-infectious causes include vasculitis, deep vein thrombosis, side effects of medication, and cancer among others.[8] It differs from hyperthermia, in that hyperthermia is an increase in body temperature over the temperature set-point, due to either too much heat production or not enough heat loss.[1]

Treatment to reduce fever is not required.[5] Treatment, however, may increase comfort and help a person rest. Measures such as putting a cool damp cloth on the forehead and having a slightly warm bath may help.[7] Medications such as ibuprofen or paracetamol may also be effective at lowering the temperature.[9] Children younger than three months with a fever should be medically assessed.[7] Hyperthermia does require treatment.[5]

Fever is one of the most common medical signs. It is part of about 30% of healthcare visits by children[5] and occurs in up to 75% of adults who are seriously sick.[10] While fever is a useful defense mechanism; treating fever does not appear to worsen outcomes.[11]

[12] Fever is viewed with greater concern by parents and healthcare professionals than it usually deserves, a phenomena known as "fever phobia".[5]

Contents

1 Definition o 1.1 Types o 1.2 Hyperpyrexia o 1.3 Hyperthermia

2 Signs and symptoms 3 Differential diagnosis 4 Pathophysiology

o 4.1 Pyrogens o 4.2 PGE2 release o 4.3 Hypothalamus o 4.4 Usefulness

5 Management

o 5.1 Conservative measures o 5.2 Medications

6 Epidemiology 7 History 8 Society and culture

o 8.1 Etymology o 8.2 Fever phobia

9 Other animals 10 References 11 Further reading 12 External links

Definition

Temperature classification

Core (rectal, esophageal, etc.)

Hypothermia <35.0 °C (95.0 °F)[13]

Normal 36.5–37.5 °C (97.7–99.5 °F)[14]

Fever >37.5 or 38.3 °C (99.5 or 100.9 °F)[1][4]

Hyperthermia >37.5 or 38.3 °C (99.5 or 100.9 °F)[1][4]

Hyperpyrexia >40.0 or 41.5 °C (104.0 or 106.7 °F)[15][16]

Note: The difference between fever and hyperthermia is the underlying mechanism.Different sources have different cuts offs for fever, hyperthermia and hyperpyrexia.

v t e

A wide range for normal temperatures has been found.[4] Fever is generally agreed to be present if the elevated temperature is caused by a raised set point and:

Temperature in the anus (rectum/rectal) is at or over 37.5–38.3 °C (99.5–100.9 °F)[1][4]

Temperature in the mouth (oral) is at or over 37.7 °C (99.9 °F)[17]

Temperature under the arm (axillary) or in the ear (otic) is at or over 37.2 °C (99.0 °F)

In healthy adult men and women, the range of normal, healthy temperatures for oral temperature is 33.2–38.2 °C (91.8–100.8 °F), for rectal it is 34.4–37.8 °C (93.9–100.0 °F), for tympanic membrane (the ear drum) it is 35.4–37.8 °C (95.7–100.0 °F), and for axillary (the armpit) it is 35.5–37.0 °C (95.9–98.6 °F).[18] Harrison's textbook of internal medicine defines a fever as a morning oral temperature of >37.2 °C (>98.9 °F) or an afternoon oral temperature of >37.7 °C (>99.9 °F) while the normal daily temperature variation is typically 0.5 °C (0.9 °F).[19]

Normal body temperatures vary depending on many factors, including age, sex, time of day, ambient temperature, activity level, and more. A raised temperature is not always a fever. For example, the temperature of a healthy person rises when he or she exercises, but this is not considered a fever, as the set-point is normal. On the other hand, a "normal" temperature may be a fever, if it is unusually high for that person. For example, medically frail elderly people have a decreased ability to generate body heat, so a "normal" temperature of 37.3 °C (99.1 °F) may represent a clinically significant fever.

Types

Performance of the various types of fevera) Fever continuesb) Fever continues to abrupt onset and remissionc) Fever remittent

d) Intermittent fevere) Undulant feverf) Relapsing fever

The pattern of temperature changes may occasionally hint at the diagnosis:

Continuous fever: Temperature remains above normal throughout the day and does not fluctuate more than 1 °C in 24 hours, e.g. lobar pneumonia, typhoid, meningitis, urinary tract infection, brucellosis, or typhus. Typhoid fever may show a specific fever pattern (Wunderlich curve of typhoid fever), with a slow stepwise increase and a high plateau. (Drops due to fever-reducing drugs are excluded.)

Intermittent fever: The temperature elevation is present only for a certain period, later cycling back to normal, e.g. malaria, kala-azar, pyaemia, or septicemia. Following are its types [20]

o Quotidian fever, with a periodicity of 24 hours, typical of Plasmodium falciparum or Plasmodium knowlesi malaria

o Tertian fever (48-hour periodicity), typical of Plasmodium vivax or Plasmodium ovale malaria

o Quartan fever (72-hour periodicity), typical of Plasmodium malariae malaria.

Remittent fever: Temperature remains above normal throughout the day and fluctuates more than 1 °C in 24 hours, e.g., infective endocarditis.

Pel-Ebstein fever : A specific kind of fever associated with Hodgkin's lymphoma, being high for one week and low for the next week and so on. However, there is some debate as to whether this pattern truly exists.[21]

A neutropenic fever, also called febrile neutropenia, is a fever in the absence of normal immune system function. Because of the lack of infection-fighting neutrophils, a bacterial infection can spread rapidly; this fever is, therefore, usually considered to require urgent medical attention. This kind of fever is more commonly seen in people receiving immune-suppressing chemotherapy than in apparently healthy people.

Febricula is an old term for a low-grade fever, especially if the cause is unknown, no other symptoms are present, and the patient recovers fully in less than a week.[22]

Hyperpyrexia

Hyperpyrexia is a fever with an extreme elevation of body temperature greater than or equal to 41.5 °C (106.7 °F).[23] Such a high temperature is considered a medical emergency as it may indicate a serious underlying condition or lead to significant side effects.[24] The most common cause is an intracranial hemorrhage.[23]

Other possible causes include sepsis, Kawasaki syndrome,[25] neuroleptic malignant syndrome, drug effects, serotonin syndrome, and thyroid storm.[24] Infections are the most common cause of fevers, however as the temperature rises other causes become more common.[24] Infections commonly associated with hyperpyrexia include roseola, rubeola and enteroviral infections.[25] Immediate aggressive cooling to less than 38.9 °C (102.0 °F) has been found to improve survival.[24] Hyperpyrexia differs from hyperthermia in that in hyperpyrexia the body's temperature regulation mechanism sets the body temperature above the normal temperature, then generates heat to achieve this temperature, while in hyperthermia the body temperature rises above its set point due to an outside source.[23]

Hyperthermia

Hyperthermia is an example of a high temperature that is not a fever. It occurs from a number of causes including heatstroke, neuroleptic malignant syndrome, malignant hyperthermia, stimulants such as amphetamines and cocaine, idiosyncratic drug reactions, and serotonin syndrome.

Signs and symptoms

Michael Ancher, "The Sick Girl", 1882, Statens Museum for Kunst

A fever is usually accompanied by sickness behavior, which consists of lethargy, depression, anorexia, sleepiness, hyperalgesia, and the inability to concentrate.[26][27][28]

Differential diagnosis

Fever is a common symptom of many medical conditions:

Infectious disease , e.g., influenza, HIV, malaria, Ebola, infectious mononucleosis, or gastroenteritis, Lyme disease

Various skin inflammations, e.g., boils, or abscess Immunological diseases, e.g., lupus erythematosus,

sarcoidosis, inflammatory bowel diseases, Kawasaki disease, Still disease, Horton disease, granulomatosis with polyangiitis, autoimmune hepatitis

Tissue destruction, which can occur in hemolysis, surgery, infarction, crush syndrome, rhabdomyolysis, cerebral bleeding, etc.

Reaction to incompatible blood products Cancers , most commonly kidney cancer and leukemia and

lymphomas Metabolic disorders , e.g., gout or porphyria Thrombo-embolic processes, e.g., pulmonary embolism or

deep venous thrombosis

Persistent fever that cannot be explained after repeated routine clinical inquiries is called fever of unknown origin.

Pathophysiology

Hyperthermia: Characterized on the left. Normal body temperature (thermoregulatory set point) is shown in green, while the hyperthermic temperature is shown in red. As can be seen, hyperthermia can be conceptualized as an increase above the thermoregulatory set point.Hypothermia: Characterized in the center: Normal body temperature is shown in green, while the hypothermic temperature is shown in blue. As can be seen, hypothermia can be conceptualized as a decrease below the thermoregulatory set point.Fever: Characterized on the right: Normal body temperature is shown in green. It reads "New Normal" because the thermoregulatory set point has risen. This has caused what was the normal body temperature (in blue) to be considered hypothermic.

Temperature is ultimately regulated in the hypothalamus. A trigger of the fever, called a pyrogen, causes a release of prostaglandin E2 (PGE2). PGE2 then in turn acts on the hypothalamus, which generates a systemic response back to the rest of the body, causing heat-creating effects to match a new temperature level.

In many respects, the hypothalamus works like a thermostat.[29] When the set point is raised, the body increases its temperature through both active generation of heat and retention of heat. Peripheral vasoconstriction both reduces heat loss through the skin and causes the person to feel cold. If these measures are insufficient to make the blood temperature in the brain match the new set point in the hypothalamus, then shivering begins in order to use muscle movements to produce more heat. When the hypothalamic set point moves back to baseline either spontaneously or with medication, the reverse of these processes (vasodilation, end of shivering and nonshivering heat production) and sweating are used to cool the body to the new, lower setting.

This contrasts with hyperthermia, in which the normal setting remains, and the body overheats through undesirable retention of excess heat or over-production of heat.[29] Hyperthermia is usually

the result of an excessively hot environment (heat stroke) or an adverse reaction to drugs. Fever can be differentiated from hyperthermia by the circumstances surrounding it and its response to anti-pyretic medications.

Pyrogens

A pyrogen is a substance that induces fever. These can be either internal (endogenous) or external (exogenous) to the body. The bacterial substance lipopolysaccharide (LPS), present in the cell wall of some bacteria, is an example of an exogenous pyrogen. Pyrogenicity can vary: In extreme examples, some bacterial pyrogens known as superantigens can cause rapid and dangerous fevers. Depyrogenation may be achieved through filtration, distillation, chromatography, or inactivation.

Endogenous

In essence, all endogenous pyrogens are cytokines, molecules that are a part of the immune system. They are produced by activated immune cells and cause the increase in the thermoregulatory set point in the hypothalamus. Major endogenous pyrogens are interleukin 1 (α and β)[30] and interleukin 6 (IL-6). Minor endogenous pyrogens include interleukin-8, tumor necrosis factor-β, macrophage inflammatory protein-α and macrophage inflammatory protein-β as well as interferon-α, interferon-β, and interferon-γ.[30] Tumor necrosis factor-α also acts as a pyrogen. It is mediated by interleukin 1 (IL-1) release.[31]

These cytokine factors are released into general circulation, where they migrate to the circumventricular organs of the brain due to easier absorption caused by the blood–brain barrier's reduced filtration action there. The cytokine factors then bind with endothelial receptors on vessel walls, or interact with local microglial cells. When these cytokine factors bind, the arachidonic acid pathway is then activated.

Exogenous

One model for the mechanism of fever caused by exogenous pyrogens includes LPS, which is a cell wall component of gram-negative bacteria. An immunological protein called lipopolysaccharide-binding protein (LBP) binds to LPS. The LBP–LPS

complex then binds to the CD14 receptor of a nearby macrophage. This binding results in the synthesis and release of various endogenous cytokine factors, such as interleukin 1 (IL-1), interleukin 6 (IL-6), and the tumor necrosis factor-alpha. In other words, exogenous factors cause release of endogenous factors, which, in turn, activate the arachidonic acid pathway.

PGE2 release

PGE2 release comes from the arachidonic acid pathway. This pathway (as it relates to fever), is mediated by the enzymes phospholipase A2 (PLA2), cyclooxygenase-2 (COX-2), and prostaglandin E2 synthase. These enzymes ultimately mediate the synthesis and release of PGE2.

PGE2 is the ultimate mediator of the febrile response. The set point temperature of the body will remain elevated until PGE2 is no longer present. PGE2 acts on neurons in the preoptic area (POA) through the prostaglandin E receptor 3 (EP3). EP3-expressing neurons in the POA innervate the dorsomedial hypothalamus (DMH), the rostral raphe pallidus nucleus in the medulla oblongata (rRPa), and the paraventricular nucleus (PVN) of the hypothalamus . Fever signals sent to the DMH and rRPa lead to stimulation of the sympathetic output system, which evokes non-shivering thermogenesis to produce body heat and skin vasoconstriction to decrease heat loss from the body surface. It is presumed that the innervation from the POA to the PVN mediates the neuroendocrine effects of fever through the pathway involving pituitary gland and various endocrine organs.

Hypothalamus

The brain ultimately orchestrates heat effector mechanisms via the autonomic nervous system. These may be:

Increased heat production by increased muscle tone, shivering and hormones like epinephrine (adrenaline)

Prevention of heat loss, such as vasoconstriction.

In infants, the autonomic nervous system may also activate brown adipose tissue to produce heat (non-exercise-associated thermogenesis, also known as non-shivering thermogenesis).

Increased heart rate and vasoconstriction contribute to increased blood pressure in fever.

Usefulness

There are arguments for and against the usefulness of fever, and the issue is controversial.[32][33] There are studies using warm-blooded vertebrates [34] and humans [35] in vivo, with some suggesting that they recover more rapidly from infections or critical illness due to fever. Studies suggest reduced mortality in bacterial infections when fever was present.[36]

In theory, fever can aid in host defense.[32] There are certainly some important immunological reactions that are sped up by temperature, and some pathogens with strict temperature preferences could be hindered.[37]

Research[38] has demonstrated that fever assists the healing process in several important ways:

Increased mobility of leukocytes Enhanced leukocyte phagocytosis Endotoxin effects decreased Increased proliferation of T cells[39]

Management

Fever should not necessarily be treated.[40] Most people recover without specific medical attention.[41] Although it is unpleasant, fever rarely rises to a dangerous level even if untreated. Damage to the brain generally does not occur until temperatures reach 42 °C (107.6 °F), and it is rare for an untreated fever to exceed 40.6 °C (105 °F).[40]

Conservative measures

Some limited evidence supports sponging or bathing feverish children with tepid water.[42] The use of a fan or air conditioning may somewhat reduce the temperature and increase comfort. If the temperature reaches the extremely high level of hyperpyrexia, aggressive cooling is required.[24] In general, people are advised to

keep adequately hydrated.[43] Whether increased fluid intake improves symptoms or shortens respiratory illnesses such as the common cold is not known.[44]

Medications

Medications that lower fevers are called antipyretics. The antipyretic ibuprofen is effective in reducing fevers in children.[45] It is more effective than acetaminophen (paracetamol) in children. Ibuprofen and acetaminophen may be safely used together in children with fevers.[46][47] The efficacy of acetaminophen by itself in children with fevers has been questioned.[48] Ibuprofen is also superior to aspirin in children with fevers.[49] Additionally, aspirin is not recommended in children and young adults (those under the age of 16 or 19 depending on the country) due to the risk of Reye's syndrome.[50]

Using both paracetamol and ibuprofen at the same time or alternating between the two is more effective at decreasing fever than using only paracetamol or ibuprofen.[51] It is not clear if it increases child comfort.[51]

Epidemiology

About 5% of people who go to an emergency room have a fever.[52]

History

A number of types of fever were known as early as 460 BC to 370 BC when Hippocrates was practicing medicine including that due to malaria (tertian or every 2 days and quartan or every 3 days).[53] It also became clear around this time that fevers were a symptom of a disease rather than a disease in and of itself.[53]

Society and culture

Etymology

Pyrexia is from the Greek pyr meaning fire. Febrile is from the Latin word febris, meaning fever, and archaically known as ague.

Fever phobia

Fever phobia is the name given by medical experts to parents' misconceptions about fever in their children. Among them, many parents incorrectly believe that fever is a disease rather than a medical sign, that even low fevers are harmful, and that any temperature even briefly or slightly above the oversimplified "normal" number marked on a thermometer is a clinically significant fever.[54] They are also afraid of harmless side effects like febrile seizures and dramatically overestimate the likelihood of permanent damage from typical fevers.[54] The underlying problem, according to professor of pediatrics Barton D. Schmitt, is "as parents we tend to suspect that our children’s brains may melt."[55]

As a result of these misconceptions parents are anxious, give the child fever-reducing medicine when the temperature is technically normal or only slightly elevated, and interfere with the child's sleep to give the child more medicine.[54]

Other animals

Fever is an important feature for the diagnosis of disease in domestic animals. The body temperature of animals, which is taken rectally, is different from one species to another. For example, a horse is said to have a fever above 101 °F (38.3 °C).[56] In species that allow the body to have a wide range of "normal" temperatures, such as camels,[57] it is sometimes difficult to determine a febrile stage.

Fever can also be behaviorally induced by invertebrates that do not have immune-system based fever. For instance, some species of grasshopper will thermoregulate to achieve body temperatures that are 2 - 5 °C higher than normal in order to inhibit the growth of fungal pathogens such as Beauveria bassiana and Metarhizium acridum.[58] Honeybee colonies are also able to induce a fever in response to a fungal parasite Ascosphaera apis. [58]

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Further reading

Rhoades, R. and Pflanzer, R. Human physiology, third edition, chapter 27 Regulation of body temperature, p. 820 Clinical focus: pathogenesis of fever. ISBN 0-03-005159-2

External links

Wikimedia Commons has media related to Fever.

Fever and Taking Your Child's Temperature US National Institute of Health factsheet Drugs most commonly associated with the adverse event

Pyrexia (Fever) as reported the FDA

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v t e

Symptoms and signs: general / constitutional (R50–R61, 780.6–780.9)

Temperature

heat:

Fever o Fever of unknown origin o Drug-induced fever o Postoperative fever

Hyperhidrosis o e.g., Sleep hyperhidrosis; "sweating"

Hyperpyrexia Hyperthermia

cold: Chills Hypothermia

Aches/Pains

Headache Chronic pain Cancer pain

Malaise and fatigue

Atrophy o e.g., Muscular atrophy

Debility (or asthenia) Lassitude Lethargy Muscle tremors Tenderness

Miscellaneous

Flu-like symptoms

Categories:

Fever