This is about the medical condition. For other uses, see Fever (disambiguation).

Symptom/Sign: Fever
Classifications and external resources

An analogue medical thermometer showing the temperature of 38. A symptom' (from Greek σύμπτωμα, "accident misfortune that which befalls" from συμπίπτω, "I befall" from A Sign is an indication of some fact or quality and a medical sign is an objective indication of some medical fact or quality that is detected by a Physician Medical thermometers are used for measuring human Body temperature, with the tip of the thermometer being inserted either into the mouth ( oral temperature 7 °C
ICD-10	R50.
ICD-9	780.6
DiseasesDB	18924
eMedicine	med/785
MeSH	D005334

Fever (also known as pyrexia, from the Greek pyretos meaning fire, or a febrile response, from the Latin word febris, meaning fever, and archaically known as ague) is a frequent medical symptom that describes an increase in internal body temperature to levels above normal. The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings R00-R69 - Symptoms and Signs (R00-R09 Circulatory and Respiratory systems ( Abnormalities of Heart beat The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. The Diseases Database is a free Website that provides information about the relationships between medical conditions Symptoms, and Medications. eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely two medical doctors Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. In Roman mythology, Febris ("fever" was the goddess who embodied but also protected people from 'fever' and 'malaria' Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the A symptom' (from Greek σύμπτωμα, "accident misfortune that which befalls" from συμπίπτω, "I befall" from Core temperature, also called core body temperature, is the operating Temperature of an Organism, specifically in deep structures of the body such as the Fever is most accurately characterized as a temporary elevation in the body's thermoregulatory set-point, usually by about 1–2°C.

Fever differs from hyperthermia; hyperthermia is an increase in body temperature over the body's thermoregulatory set-point (due to excessive heat production or insufficient thermoregulation, or both). Hyperthermia, in its advanced state referred to as heat stroke or sunstroke, is an acute condition which occurs when the Body produces or absorbs more Thermoregulation is the ability of an Organism to keep its body temperature within certain boundaries even when temperature surrounding is very different Carl Wunderlich discovered that fever is not a disease but a symptom of disease. Carl Reinhold August Wunderlich (1815-1877 was a German physician pioneer psychiatrist and medical professor

The elevation in thermoregulatory set-point means that the previous "normal body temperature" is considered hypothermic, and effector mechanisms kick in. Hypothermia is a condition in which an organism's temperature drops below that required for normal Metabolism and bodily functions The person who is developing the fever has a cold sensation, and an increase in heart rate, muscle tone and shivering attempt to counteract the perceived hypothermia, thereby reaching the new thermoregulatory set-point. Measuring heart rate The Pulse rate (which in most people is identical to the heart rate can be measured at any point on the body where an Artery 's pulsation In Physiology, Medicine, and Anatomy, muscle tone (aka residual muscle tension or tonus) is the continuous and passive partial Hypothermia is a condition in which an organism's temperature drops below that required for normal Metabolism and bodily functions A fever is one of the body's mechanisms to try to neutralize the perceived threat inside the body, be it bacteria or a virus.

Measurement and normal variation

When a patient has or is suspected of having a fever, that person's body temperature is measured using a thermometer.

At a first glance, fever is present if:

• temperature in the anus (rectum/rectal) or in the ear (otic) is at or over 38. 0°C (100. 4°F)
• temperature in the mouth (oral) is at or over 37. 5°C (99. 5°F)
• temperature under the arm (axillary) is at or over 37. 2°C (99. 0°F)

The common oral measurement of normal human body temperature is 36. 8±0. 7 °C (98. 2±1. 3 °F). This means that any oral temperature between 35. 9 and 37. 5 °C (96. 9 and 99. 5 °F) is likely to be normal.

However, there are many variations in normal body temperature, and this needs to be considered when measuring for fever. The values given are for an otherwise healthy, non-fasting adult, dressed comfortably, indoors, in a room that is kept at a normal room temperature (73° to 76°F or 22. 7°C to 24. 4°C) , during the morning, but not shortly after arising from sleep. Furthermore, for oral temperatures, the subject must not have eaten, drunk, or smoked anything in at least the previous fifteen to twenty minutes.

Body temperature normally fluctuates over the day, with the lowest levels around 4 a. m. and the highest around 6 p. m. ^[1] Therefore, an oral temperature of 37. 2°C (99. 0°F) would strictly be a fever in the morning, but not in the afternoon. An oral body temperature reading up to 37. 5 °C (99. 5 °F) in the early/late afternoon or early/late evening also wouldn't be a fever. Normal body temperature may differ as much as 1. 0 °F between individuals or from day to day. In women, temperature differs at various points in the menstrual cycle, and this can be used for family planning (although temperature is only one of the variables). The menstrual cycle is a recurring cycle of physiologic changes that occurs in reproductive-age Females Overt menstruation (where there is blood flow from the Fertility awareness (FA refers to a set of practices used to determine the fertile and infertile phases of a woman's Menstrual cycle. Temperature is increased after meals and eating, and psychological factors also influence body temperature.

There are different locations where temperature can be measured, and these differ in temperature variability. Tympanic membrane thermometers measure radiant heat energy from the tympanic membrane (infrared). The tympanic membrane (also tympanum or myrinx is a thin membrane that separates the External ear from the Middle ear. The thermometer is a device that measures Temperature or Temperature gradient using a variety of different principles it comes from the Greek roots These may be very convenient, but may also show more variability.

Children develop higher temperatures with activities like playing, but this is not fever because their set-point is normal. Elderly patients may have a decreased ability to generate body heat during a fever, so even a low-grade fever can have serious underlying causes in geriatrics. Geriatrics is the branch of Medicine that focuses on health care of the elderly

Mechanism

Temperature is regulated in the hypothalamus, in response to prostaglandin E2 (PGE2). The hypothalamus links the Nervous system to the Endocrine system via the Pituitary gland (hypophysis In Medicine, dinoprostone, is a naturally occurring Prostaglandin E2 (PGE2 PGE2 release, in turn, comes from a trigger, a pyrogen. The hypothalamus generates a response back to the rest of the body, making it increase the temperature set-point.

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.

Pyrogens

A pyrogen is a substance that induces fever. These can be either internal (endogenous) or external (exogenous). The word endogenous means "arising from within" the opposite of Exogenous. In Economics, an externality is an impact on any party not directly involved in an economic decision Exogenous (or exogeneous) (from the Greek words "exo" and "gen" meaning "outside" and "production" refers to an action or The bacterial substance lipopolysaccharide (LPS) is an example of an exogenous pyrogen. Lipopolysaccharides ( LPS) are large Molecules consisting of a Lipid and a Polysaccharide joined by a Covalent bond; they are found

Endogenous

The cytokines (such as interleukin 1) are a part of the innate immune system, produced by phagocytic cells, and cause the increase in the thermoregulatory set-point in the hypothalamus. Cytokines are a category of signalling Proteins and Glycoproteins that like Hormones and Neurotransmitters, are used extensively in cellular Interleukin-1 (IL-1 is one of the first Cytokines ever described Immune system|Adaptive immune systemThe innate immune system comprises the cells and mechanisms that defend the host from infection by other organisms in a non-specific manner Phagocytes are cells that are found in the blood bone marrow and other tissues of Vertebrates. Other examples of endogenous pyrogens are interleukin 6 (IL-6), and tumor necrosis factor-alpha. Tumor necrosis factor ( TNF, cachexin or cachectin and formally known as Tumor necrosis factor-alpha) is a Cytokine involved in systemic

These cytokine factors are released into general circulation where they migrate to the circumventricular organs of the brain, where the blood-brain barrier is reduced. Circumventricular organs (CVO are so named because they are positioned at distinct sites around the margin of the Ventricular system of the brain The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain The blood-brain barrier (BBB is a metabolic or cellular structure in the Central nervous system (CNS that restricts the passage of various chemical substances and microscopic The cytokine factors bind with endothelial receptors on vessel walls, or interact with local microglial cells. The endothelium is the thin layer of cells that line the interior surface of Blood vessels forming an interface between circulating Blood in the Microglia are a type of Glial cell that acts as the first and main form of active immune defense in the Central nervous system (CNS When these cytokine factors bind, they activate the arachidonic acid pathway. Arachidonic acid (AA sometimes ARA is an Omega-6 fatty acid 204(ω-6

Exogenous

One model for the mechanism of fever caused by exogenous pyrogens includes LPS, which is a cell wall component of gram-negative bacteria. Gram-negative bacteria are those Bacteria that do not retain Crystal violet dye in the Gram staining protocol An immunological protein called lipopolysaccharide-binding protein (LBP) binds to LPS. Lipopolysaccharide binding protein, also known as LBP, is a human Gene. The LBP–LPS complex then binds to the CD14 receptor of a nearby macrophage. Cluster of differentiation 14 also known as CD14 is a human Gene. Macrophages ( Greek: "big eaters" from makros "large" + phagein "eat" ( Mø) are cells within the tissues that 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. Cytokines are a category of signalling Proteins and Glycoproteins that like Hormones and Neurotransmitters, are used extensively in cellular 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. Arachidonic acid (AA sometimes ARA is an Omega-6 fatty acid 204(ω-6 This pathway (as it relates to fever), is mediated by the enzymes phospholipase A2 (PLA2), cyclooxygenase-2 (COX-2), and prostaglandin E2 synthase. Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins A phospholipase is an enzyme that converts Phospholipids into Fatty acids and other Lipophilic substances Prostaglandin E synthase (or PGE synthase) is an enzyme involved in Eicosanoid and Glutathione metabolism a member of MAPEG family. 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). The preoptic area is a region of the Hypothalamus. According to the MeSH classification it is considered part of the anterior hypothalamus Prostaglandin E receptor 3 (subtype EP3, also known as PTGER3, is a Prostaglandin receptor, but also denotes the human Gene encoding it 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 of the hypothalamus (PVN). The Dorsomedial hypothalamic nucleus is a nucleus of the Hypothalamus. A raphe has different uses In science Pronounced "RAY-fee") it is most commonly used when describing Diatoms, Seeds, and Animal The medulla oblongata is the lower portion of the Brainstem. It deals with autonomic functions such as breathing and blood pressure The paraventricular nucleus (PVN is an aggregation of neurons in the Hypothalamus which produces many Hormones. The hypothalamus links the Nervous system to the Endocrine system via the Pituitary gland (hypophysis 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. The pituitary gland, or hypophysis, is an Endocrine gland about the size of a Pea. Endocrinology (from Greek grc ἔνδον endon, "within" grc κρῑνω krīnō, "to separate" and grc -λογία

Hypothalamus response

The brain ultimately orchestrates heat effector mechanisms via the autonomic nervous system. &trade The autonomic nervous system ( ANS) (or visceral nervous system) is the part of the Peripheral nervous system that acts as a Control These may be

• increased heat production by increased muscle tone, shivering and hormones like epinephrine. In Physiology, Medicine, and Anatomy, muscle tone (aka residual muscle tension or tonus) is the continuous and passive partial
• prevention of heat loss, such as vasoconstriction. Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels particularly the large Arteries, Arterioles

The autonomic nervous system may also activate brown adipose tissue to produce heat (non-exercise-associated thermogenesis, also known as non-shivering thermogenesis), but this seems mostly important for babies. Brown adipose tissue ( BAT) or brown fat is one of the two types of Adipose tissue (the other being White adipose tissue) that is present in many Thermogenesis is the process of Heat production in organisms It occurs mostly in Warm-blooded animals but a few species of Thermogenic plants exist Increased heart rate and vasoconstriction contribute to increased blood pressure in fever. Blood pressure is also the title of a short story by Damon Runyan in Guys and Dolls and Other Stories

Types

According to one common rule of thumb, pyrexia (fever) is generally classified for convenience as:

The last is a medical emergency because it approaches the upper limit compatible with human life. A medical emergency is an Injury or Illness that is acute and poses an immediate risk to a person's life or long term health

Most of the time, fever types can not be used to find the underlying cause. However, there are specific fever patterns that may occasionally hint the diagnosis:

• 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. Diagnosis is the identification by Process of elimination, of the nature of anything Pel-Ebstein fever is a rarely seen condition noted in patients with Hodgkin's lymphoma in which the patient experiences Fevers which cyclicly increase then decrease Hodgkin's lymphoma, also known as Hodgkin's disease is a type of Lymphoma first described by Thomas Hodgkin in 1832 However, there is some debate as to whether this pattern truly exists. ^[2]
• 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, urinary tract infection, brucellosis, or typhus. Pneumonia is an inflammatory illness of the Lung. Frequently it is described as lung Parenchyma / alveolar inflammation and abnormal Typhoid fever, also known as enteric fever, bilious fever, Yellow Jack or commonly just typhoid, is an illness caused by the Bacterium A urinary tract infection ( UTI) is a bacterial Infection that affects any part of the Urinary tract. Brucellosis, also called undulant fever, or Malta fever, is a highly contagious Zoonosis caused by ingestion of unsterilized Milk Typhus is any of several similar diseases caused by Louse -borne bacteria Typhoid fever may show a specific fever pattern, with a slow stepwise increase and a high plateau. Typhoid fever, also known as enteric fever, bilious fever, Yellow Jack or commonly just typhoid, is an illness caused by the Bacterium
• Intermittent fever: Elevated temperature is present only for some hours of the day and becomes normal for remaining hours, e. g. malaria, kala-azar, pyaemia, or septicemia. Malaria is a vector -borne Infectious disease caused by Protozoan Parasites It is widespread in tropical and subtropical regions including Visceral leishmaniasis (VL also known as kala-azar and black fever, is the most severe form of Leishmaniasis. Pyaemia (or pyemia) is a type of septicaemia that leads to widespread Abscesses of a metastatic nature Sepsis is a serious medical condition characterized by a whole-body inflammatory state (called a Systemic inflammatory response syndrome or SIRS caused In malaria, there may be a fever with a periodicity of 24 hours (quotidian), 48 hours (tertian fever), or 72 hours (quartan fever, indicating Plasmodium malariae). Plasmodium malariae is a parasitic Protozoa that causes Malaria in humans and animals These patterns may be less clear in travelers.
• Remittent fever: Temperature remains above normal throughout the day and fluctuates more than 1°C in 24 hours, e. g. infective endocarditis. Endocarditis is an Inflammation of the inner layer of the Heart, the Endocardium.

A neutropenic fever, also called febrile neutropenia, is a fever in the absence of normal immune system function. Febrile neutropenia is the development of Fever, often with other signs of Infection, in a patient with Neutropenia, an abnormally low number of Neutrophil Because of the lack of infection-fighting neutrophils, a bacterial infection can spread rapidly and this fever is therefore usually considered a medical emergency. Neutrophil granulocytes, generally referred to as neutrophils, are the most abundant type of White blood cells in humans and form an essential part of the This kind of fever is more commonly seen in people receiving immune-suppressing chemotherapy than in apparently healthy people. Chemotherapy, in its most general sense refers to treatment of disease by chemicals that kill cells specifically those of micro-organisms or Cancer.

Febricula^[3] is a mild fever of short duration, of indefinite origin, and without any distinctive pathology.

Causes

Fever is a common symptom of many medical conditions:

• Infectious disease, e. A symptom' (from Greek σύμπτωμα, "accident misfortune that which befalls" from συμπίπτω, "I befall" from An infectious disease is a clinically evident Disease resulting from the presence of Pathogenic microbial agents including Pathogenic viruses Pathogenic g. influenza, common cold, HIV, malaria, infectious mononucleosis, or gastroenteritis. Acute viral nasopharyngitis or acute coryza, usually known as the common cold, is a highly contagious viral Infectious disease of the Human immunodeficiency virus ( HIV) is a Lentivirus (a member of the Retrovirus family that can lead to acquired immunodeficiency syndrome Malaria is a vector -borne Infectious disease caused by Protozoan Parasites It is widespread in tropical and subtropical regions including Infectious mononucleosis, also known as Pfeiffer's disease, mono (in The United States of America) and more commonly known as glandular Gastroenteritis (also known as gastro, gastric flu, and stomach flu, although unrelated to Influenza) is Inflammation of the
• Various skin inflammations, e. Inflammation ( Latin, inflamatio, to set on fire is the complex biological response of vascular tissues to harmful stimuli such as Pathogens g. boils, pimples, acne, or abscess. Boil or furuncle is a skin disease caused by the infection of Hair follicles resulting in the localized accumulation of Pus and dead tissue A pimple is a result of a blockage of the Skin 's Pore. It can be a Pustule or Papule. Acne vulgaris (commonly called acne) is a Skin disease caused by changes in the Pilosebaceous units (skin structures consisting of a Hair follicle An abscess (abscessus is a collection of Pus (dead Neutrophils) that has accumulated in a cavity formed by the tissue on the basis of an infectious process
• Immunological diseases, e. Immunology is a broad branch of biomedical Science that covers the study of all aspects of the Immune system in all Organisms It deals with g. lupus erythematosus, sarcoidosis, inflammatory bowel diseases. Systemic lupus erythematosus ( SLE or lupus,) is a chronic autoimmune disease that can be fatal though with recent medical advances fatalities are becoming Sarcoidosis, also called sarcoid (from the Greek sarx, meaning "flesh" or Besnier-Boeck disease, is an immune system disorder characterized In Medicine, inflammatory bowel disease ( IBD) is a group of inflammatory conditions of the large intestine and Small intestine
• Tissue destruction, which can occur in hemolysis, surgery, infarction, crush syndrome, rhabdomyolysis, cerebral hemorrhage, etc. Hemolysis (or haemolysis)—from the Greek Hemo-, Greek meaning blood - Lysis, meaning to break open—is the breaking Surgery (from the χειρουργική cheirourgikē, via chirurgiae meaning "hand work" is a medical specialty that uses operative manual and instrumental In Medicine, an infarction is the process resulting in a Macroscopic area of necrotic tissue in some organ caused by loss of adequate Blood supply Crush syndrome (also traumatic Rhabdomyolysis or Bywaters' syndrome) is a serious Medical condition characterized by major shock Rhabdomyolysis is the rapid breakdown ( Lysis) of Skeletal muscle tissue ( rhabdomyo) due to injury to muscle tissue A cerebral hemorrhage (or intracerebral hemorrhage, ICH) is a subtype of Intracranial hemorrhage that occurs within the Brain tissue itself
• Drug fever
  • directly caused by the drug, e. g. lamictal, progesterone, or chemotherapeutics causing tumor necrosis. Lamotrigine (marketed as Lamictal (ləˈmɪktəl by GlaxoSmithKline, called Lamictin in South Africa, he למוג'ין ( Lamogine Progesterone is a C-21 Steroid Hormone involved in the Female Menstrual cycle, Pregnancy (supports Gestation Chemotherapy, in its most general sense refers to treatment of disease by chemicals that kill cells specifically those of micro-organisms or Cancer. See also Cancer A tumor or tumour is the name for a swelling or lesion formed by an abnormal growth of cells (termed neoplastic Necrosis (in Greek Νεκρός = "dead" is the name given to unnatural Death of cells and living tissue.
  • as an adverse reaction to drugs, e. g. antibiotics or sulfa drugs. In modern usage an antibiotic is a Chemotherapeutic agent with activity against Microorganisms such as Bacteria, fungi or Protozoa There are several sulfonamide-based groups of drugs The original antibacterial sulfonamides (sometimes called simply sulfa drugs are synthetic antimicrobial agents that contain the sulfonamide
  • after drug discontinuation, e. g. heroin withdrawal. Heroin ( INN: diacetylmorphine, BAN: diamorphine) is a semi-synthetic opioid synthesized from Morphine, a derivative
• Cancers, most commonly renal cancer and leukemia and lymphomas
• Metabolic disorders, e. Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled "Kidney Cancer" redirects here For Wilms' Tumor/Nephroblastoma see Wilms' tumor. Leukemia or leukaemia (Greek leukos λευκός, "white" aima αίμα, "blood" is a Cancer of the Blood Lymphoma a type of Neoplasm that originates in Lymphocytes (a type of White blood cell in the vertebrate Immune system) Inborn errors of metabolism comprise a large class of genetic Diseases involving disorders of Metabolism. g. gout or porphyria. Gout (also called metabolic arthritis) is a disease created by a buildup of Uric acid. Porphyrias are a group of inherited or acquired disorders of certain Enzymes in the Heme biosynthetic pathway (also called Porphyrin pathway
• Thrombo-embolic processes, e. g. pulmonary embolism or deep venous thrombosis. Pulmonary embolism (PE is a blockage of the Pulmonary artery or one of its branches usually occurring when a venous Thrombus (blood clot from a vein In Medicine, deep vein thrombosis (also known as deep-vein thrombosis or deep venous thrombosis and usually abbreviated as DVT) is the formation

Persistent fever which cannot be explained after repeated routine clinical inquiries, is called fever of unknown origin. Fever of unknown origin (FUO, pyrexia of unknown origin (PUO or febris e causa ignota (febris E

Usefulness of fever

"Give me a fever, and I can cure any illness. " -- Hippocrates (ca. Hippocrates of Cos II or Hippokrates of Kos ( ca. 460 BC – ca 400 BC)

There are arguments for and against the usefulness of fever, and the issue is controversial. ^[4][5] There are studies using warm-blooded vertebrates^[6] and humans^[7] in vivo, with some suggesting that they recover more rapidly from infections or critical illness due to fever. In Biology, a warm-blooded Animal species is one whose members maintain thermal Homeostasis; that is they keep their body temperature at a roughly constant Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus In vivo ( Latin: within the living means that which takes place inside an organism.

Theoretically, fever can aid in host defense. ^[4] There are certainly some important immunological reactions that are sped up by temperature, and some pathogens with strict temperature preferences could be hindered. A pathogen (from Greek πάθος pathos "suffering passion" and γἰγνομαι (γεν- gignomai (gen- "I give birth to" infectious ^[8] The overall conclusion seems to be that both aggressive treatment of fever^[7] and too little fever control^[4] can be detrimental. This depends on the clinical situation, so careful assessment is needed.

Fevers may be useful to some extent since they allow the body to reach high temperatures. This causes an unbearable environment for some pathogens. White blood cells also rapidly proliferate due to the suitable environment and can also help fight off the harmful pathogens and microbes that invaded the body.

Research^[9] has demonstrated that fever has several important functions in the healing process:

• increased mobility of leukocytes
• enhanced leukocytes phagocytosis
• endotoxin effects decreased
• increased proliferation of T Cells^[10]
• enhanced activity of interferon ^[10]

Treatment

Fever should not necessarily be treated. Phagocytosis is the cellular process of engulfing solid particles by the Cell membrane to form an internal Phagosome, or "food vacuole Endotoxins (not to be confused with Enterotoxin) are potentially toxic, natural compounds found inside Pathogens such as Bacteria. The term cell growth is used in two different ways in Biology. Interferons ( IFN s are natural Proteins produced by the cells of the Immune system of most Vertebrates in response to challenges by foreign agents Fever is an important signal that there's something wrong in the body, and it can be used to govern medical treatment and gauge its effectiveness. Moreover, not all fevers are of infectious origin.

Even when treatment is not indicated, however, febrile patients are generally advised to keep themselves adequately hydrated, as the dehydration produced by a mild fever can be more dangerous than the fever itself. Dehydration ( hypohydration) is the removal of Water ( hydro in ancient Greek) from an object Water is generally used for this purpose, but there is always a small risk of hyponatremia if the patient drinks too much water. Hyponatremia ( British: hyponatraemia) is an Electrolyte disturbance (disturbance of the salts in the blood in which the Sodium ( Natrium For this reason, some patients drink sports drinks or electrolyte-replacing products designed specifically for this purpose. A sports drink is a Beverage designed to help athletes rehydrate as well as replenish Electrolytes Carbohydrates, and other Nutrients An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium

Most people take medication against fever because the symptoms cause discomfort. Fever increases heart rate and metabolism, thus potentially putting an additional strain on elderly patients, patients with heart disease, etc. Measuring heart rate The Pulse rate (which in most people is identical to the heart rate can be measured at any point on the body where an Artery 's pulsation Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. Heart disease is an Umbrella term for a variety for different diseases affecting the Heart. This may even cause delirium. Delirium is an acute and relatively sudden (developing over hours to days decline in attention-focus perception and Cognition. Therefore, potential benefits must be weighed against risks in these patients. In any case, fever must be brought under control in instances when fever escalates to hyperpyrexia and tissue damage is imminent. In Medicine, hyperpyrexia is an excessive and unusual elevation of set Body temperature greater than or equal to 41

Treatment of fever is normally done by lowering the set-point, but facilitating heat loss may also be effective. The former is accomplished with antipyretics such as ibuprofen or acetominophen (aspirin can be given to adults, but can cause Reye's Syndrome in children). Antipyretics are Drugs that reduce body temperature in situations such as Fever. Ibuprofen ( INN) (ˌaɪbjuːˈpɹəʊfɛn (from the now outdated nomenclature i so- bu tyl- pro panoic- phen olic acid is a Non-steroidal Paracetamol ( INN) (ˌpærəˈsiːtəmɒl -ˈsɛtə- or acetaminophen ( USAN) is a widely-used Analgesic and Antipyretic Medication Aspirin, or acetylsalicylic acid (ASA (əˌsɛtɨlsælɨˌsɪlɨk ˈæsɨd is a Salicylate drug, often used as an Analgesic to relieve Reye's syndrome is a potentially fatal Disease that causes numerous detrimental effects to many organs especially the Brain and Liver. Heat removal is generally by wet cloth or pads, usually applied to the forehead. Heat loss may also be accomplished by heat conduction, convection, radiation, or evaporation (sweating, perspiration), or a combination of these. Heat conduction or thermal conduction is the spontaneous transfer of thermal energy through matter from a region of higher Temperature to a region of lower Convection in the most general terms refers to the movement of molecules within Fluids (i Radiation, as in Physics, is Energy in the form of waves or moving Subatomic particles emitted by an atom or other body as it changes from a higher energy Evaporation is the process by which Molecules in a Liquid state (e This is particularly important for babies, where drugs should be avoided. However, using water that is too cold can induce vasoconstriction, and reduce effective heat loss. Water is a common Chemical substance that is essential for the survival of all known forms of Life. Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels particularly the large Arteries, Arterioles

References

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
• Kasper, D. L. ; Braunwald, E. ; Fauci, A. S. ; Hauser, S. L. ; Longo, D. L. ; Jameson, J. L. Harrison's Principles of Internal Medicine. Harrison's Principles of Internal Medicine is an American Textbook of Internal medicine. New York: McGraw-Hill, 2005. ISBN 0-07-139140-1.

External links

• What to do if your child has a fever from Seattle Children's Hospital
• Fever and Taking Your Child's Temperature
• US National Institute of Health factsheet
• BUPA factsheet