Many patients use the term “fever” very loose and often think that they feel too hot, too cold or sweaty, but they have not really measured their temperature.
Fever is an elevated body temperature (> 37.8 ° C oral or> 38.2 ° C rectal) or simply an increase in body temperature over the personal daily value addition. Fever occurs when the body thermostat resets (in the hypothalamus) at a higher temperature, primarily in response to an infection. Elevated body temperature, which is not caused by resetting the target value is referred to as hyperthermia. Many patients use the term “fever” very loose and often think that they feel too hot, too cold or sweaty, but they have not really measured their temperature. Symptoms occur mainly due to the reasons that cause the fever, although fever can also cause chills, sweating and discomfort alone, patients are flushed by and feel heated. Pathophysiology During a 24-hour period the temperature varies from a low in the early morning to the highest in the late afternoon, maximum fluctuation is approximately 0.6 ° C. The body temperature is determined by a balance between the heat production of the fabric, in particular of the liver and muscles, as well as the heat loss in the body’s periphery. In a healthy state, the thermoregulatory center normally holds a body temperature of the internal organs of between 37 ° and 38 ° C maintained. Fever occurs when something can increase the hypothalamic set point and so vasoconstriction and shunting of blood from the periphery triggers to reduce heat loss. Sometimes tremors, which increases the heat production induced. These processes hold on until the temperature of the blood surrounding the hypothalamus reaches the new setpoint. A change in the hypothalamic set point (eg., By anti-pyretic substances) leads to a heat loss by sweating and vasodilation. The ability to fever development in some patients (eg. As an alcoholic, very old and very young people) reduced. Fumed are fever-causing substances. Exogenous pyrogens are typically micro-organisms or their products. The best studied are the lipopolysaccharide of Gram-negative bacteria (so-called. Endotoxin) and the toxin from Staphylococcus aureus, which causes toxic shock syndrome. Fever is the result of exogenous pyrogens (TNF-alpha), induce the release of endogenous pyrogens, such as interleukin-1 (IL-1), tumor necrosis factor-alpha IL-6 and other cytokines, which then cytokine trigger receptors or exogenous pyrogens, directly trigger the “Toll-like receptors”. The synthesis of prostaglandin E2 seems to play an important role. Follow the fever Although many patients worry that fever already alone can cause damage triggered by the most acute diseases small temperature increases are well tolerated by healthy adults (d. H 38 ° to 40 °.). However, an extreme increase in temperature (typically> 41 ° C) can be harmful. Such an increase is more typical for heavy “environmental” hyperthermia, but sometimes also the result of the influence of illegal drugs (eg. As cocaine, phencyclidine), anesthetics or antipsychotics. At this temperature, protein denaturation occur and inflammatory cytokines that activate the inflammatory cascade, will be released. As a result, cellular malfunctions occur which lead to malfunction and ultimately to the failure of most of the organs; The coagulation cascade is also activated, resulting in widespread intravascular coagulation. Because fever can the BMR by about 10 to 12% for every 1 ° C increase rise above 37 ° C, it can be particularly problematic in adults with pre-existing cardiac or pulmonary insufficiency. Fever may also impair the mental status of patients with dementia. Fever can cause febrile seizures in healthy children. Etiology Many diseases can fever cause you are generally categorized as infectious diseases (most common) Neoplastic Inflammatory (including rheumatic, non-rheumatic and drug dependent) The cause of acute (d. E., Duration ? 4 days) fever in adults is most likely contagious. In patients with fever due to an infectious cause, this is almost always chronic or recurrent. it is very likely that even an isolated acute fever patients is contagious with a known inflammatory or neoplastic disease. In healthy people, acute fever is probably not the first manifestation of a chronic disease. Infectious causes virtually all infectious diseases can cause fever But overall the most likely causes are infections of the upper and lower respiratory tract infections UTI GI infections of the skin Most acute respiratory and GI infections are viral. Patient-specific and external factors also have an influence on what causes are most likely. (As such. Hospitalization recent invasive procedures, presence of urinary catheter or IV, use of artificial ventilation) Patient factors include health status, age, occupation and risk factors. External factors are those that patients suspend certain diseases – such. B. contact with infected individuals, local outbreaks, disease vectors (eg. As mosquitoes, ticks), a common use (eg. B food, water) or geographical location (eg. B residing in or last trip to an endemic area) , Some causes seem to prevail on the basis of these factors (see Table: Some causes of acute fever). Some causes of acute fever predisposition Cause No (healthy) Upper or lower respiratory infections GI infection UTI skin infection hospitalization IV catheter infection UTI (especially in patients with an indwelling catheter) pneumonia (especially in patients with a ventilator) atelectasis Postoperative wound infection (postoperative) deep vein thrombosis or pulmonary embolism diarrhea (Clostridium difficile-induced) drug hematoma transfusion reaction decubitus Travel to endemic areas coccidioidomycosis dengue fever (less frequent) diarrhea hantavirus histoplasmosis Legionnaires’ disease malaria against many drug resistant bacteria plague tularemia typhoid viral hepatitis Zika virus infection Vector exposure (in the US) ticks, Rickettsiosis, ehrlichiosis, anaplasmosis, Lyme disease, babesiosis tularemia mosquitoes: arboviral encephalitis Wild Animals: tularemia, rabies, hantavirus fleas: Plague pets: brucellosis, cat scratch disease, Q fever, toxoplasmosis birds: psittacosis reptiles: Salmonella infection bats: rabies, histoplasmosis immunodeficiency Viruses: varicella zoster virus or cytomegalovirus infections bacteria: infection by encapsulated organisms (eg. cause infection by Candida, Aspergillus, Histoplasma or Coccidioides sp, Pneumocystis jirovecii or fungi which mucormycosis. B. pneumococcus, meningococcus), Staphylococcus aureus, gram-negative bacteria (e.g., Pseudomonas aeruginosa), Nocardia sp, or Mycobacteria sp fungi. , Parasites: infection by Toxoplasma gondii, Strongyloides stercoralis, Cryptosporidium sp, microsporidia or Cystoisospora (previously Isospora) belli drugs which can increase heat production amphetamines cocaine methylenedioxymethamphetamine (MDMA or ecstasy) antipsychotics anesthetic drugs that can cause fever beta-lactam antibiotics sulfonamides phenytoin, carbamazepine procainamide, quinidine amphotericin B interferons evaluation Two general questions are only s important evaluation in acute fever: Detection of local symptoms (eg, headache, cough): These symptoms help the range of possible causes eunzuengen Localization symptom may be a part of the patients chief complaint or identified only by specific survey. The determination of whether the patient is heavy or chronically ill (especially if the disease is not recognized): Many causes of fever in healthy people are self-limiting, and many of the possible viral infections are difficult specifically zudiagnostizieren. to limit the investigation to severe or chronic diseases, help a lot of expensive, unnecessary and often fruitless process can be avoided. History The Anamneseder present illness should amount and duration of fever and the methods for measuring temperature include obvious loads (violent, trembling with teeth rattling chills-not just feeling cold) suggest that the fever was caused by an infection, but are not otherwise specific. Pain is an important indication of the possible source; the patient should be asked about pain in the ears, head, neck, teeth, neck, chest, abdomen, flank, rectum, muscles and joints. Other local symptoms are nasal congestion and / or runny nose, cough, diarrhea and urinary symptoms (increased urination, urgency, dysuria). Presence of rash (including its quality, location and time of occurrence relative to other symptoms) and lymphadenopathy can help. Infected contacts and their diagnosis should be identified. The review of systems should recognize symptoms of chronic disease, including recurrent fever, night sweats and weight loss. History should include in particular the following points: Recent surgery Known conditions that infections favor (eg, HIV infection, diabetes, cancer, organ transplantation, sickle cell disease, valvular heart disease-particularly if an artificial valve is available.) Other known diseases fever favor (z. B. rheumatological disease, SLE, gout, sarcoidosis, hyperthyroidism, cancer) information on the recent trip should include location, time since returning, location area (eg. as in the hinterland, only in cities), carried out vaccinations before travel and any use of prophylactic antimalarial drugs (if necessary). All patients should be asked about possible risks (eg., Via unsafe food or water, insect bites, contact with animals or unprotected sex). Performed vaccinations, particularly against hepatitis A and B, and against organisms that cause meningitis, influenza or pneumococcal infection should be considered. The history of drug intake should include the following: drugs that are known to cause fever (see Table: Some causes of acute fever) medications that promote an increased risk of infection. (. For example, corticosteroids, anti-TNF drugs, chemotherapeutic agents, and antirejection drugs anderenImmunsuppressiva) illegal or inappropriate use of the injection of drugs (the following favor: endocarditis, hepatitis, septic pulmonary embolism, and skin and soft tissue infections) Physical Examination Physical examination begins with the detection of fever. Fever is most accurately determined by measuring the rectal temperature. Oral temperatures are about 0.6 ° C generally lower and can occur for many reasons, such as last taking a cold drink, mouth breathing, hyperventilation and insufficient measurement time (up to several minutes with mercury thermometer required) mistakenly be even lower. The temperature measurement of the eardrum by infrared sensor is less accurate than rectal temperature. to monitor the skin temperature by means of temperature sensitive crystals that are incorporated into plastic strips and placed on the forehead, is ineffective for the detection of the increase in the core temperature. Other vital signs are checked for the presence of tachypnea, tachycardia, or hypotension. For patients with local symptoms, checking elsewhere in the MSD Manual continues. For patients with fever without local symptoms, a thorough examination is necessary because s clues to the diagnosis in another organ system can give. The general appearance of the patient, including any weakness, lethargy, confusion, cachexia, and worry is observed. The entire skin should be evaluated for rash, and in particular petechial or hemorrhagic rash and any lesions or areas of erythema or blistering that may indicate skin or soft tissue infections. Neck, armpits and epitrochleare and inguinal areas should be examined for adenopathy. In hospitalized patients, the presence of ITS, night, urinary catheter, and all other hoses or pipes that have been introduced into the body should be respected. When patients have recently undergone surgery, incision sites should be thoroughly inspected. For the head and neck examination, the following should be done: eardrum: Investigation on infection sinuses (frontal and maxillary sinuses): tapping temporal arteries: scanning for susceptibility nose: Inspect for clogging and secretions (clear or purulent) Eyes: screening for conjunctivitis or jaundice Fundi: assaying for Roth spots (indicating a endocarditis suggesting) oropharynx and gums: assaying for inflammation or ulceration (including all lesions candidiasis, on Immunschwächehinweist) neck: Bow to recognize symptoms, stiffness, or both, suggesting meningism points and scan on adenopathy the lungs are crackles or examined signs of consolidation, and the heart is for murmurs bugged (suggesting possible endocarditis). The abdomen is to be scanned on hepatosplenomegaly and sensitivity (indicating an infection). The edges are sensed through the kidneys of sensitivity (which is on, indicating pyelonephritis). A pelvic examination should be performed in women, to check the cervical motion or uterine sensitivity; a genital examination is performed in men to check discharge from the urethra and local tenderness. The rectum is examined for tenderness and swelling out, which may indicate perirectal abscess (which are occult in immunosuppressed patients). All major joints should be examined for swelling, redness and sensitivity (indicating a joint infection or rheumatic disease). The hands and feet are to the fingers and toes peaks (Osler nodes), and not painful hemorrhagic spots on the palms or soles (Janeway lesions) be examined for signs of endocarditis, including splinter hemorrhages under the nails, painful erythematous subcutaneous nodules. The spine is knocked on focal sensitivity. A neurological examination is performed to focal deficits aufzudecken.Rote flags The following results are of particular importance: altered mental headache, stiff neck, or both petechial rash vacuum dyspnea Significant tachycardia or tachypnea body temperature> 40 ° C or <35 ° C Recent travel to an area in which serious diseases (eg. as malaria) are endemic last use of immunosuppressants interpretation of results the extent of the increase in body temperature usually says nothing about the likelihood of an infectious cause of. Manifestation of fever that once regarded as significant, it is not. determined probability of a serious Erkrankungist. If a serious illness is suspected, immediate and aggressive investigations and frequent hospitalization required. Red flag findings strongly in a serious condition. As in the following: headache, stiff neck, petechial or purpuric rash indicate meningitis. Tachycardia (usually via a small rise out with fever) and tachypnea, with or without hypotension or mental status changes, suggest a sepsis. Malaria should be suspected in patients who have recently traveled to endemic areas. Immune deficiencies, whether caused by a known disorder, or use of immunosuppressive drugs or assumed on the basis of inspection results (eg. As weight loss, oral candidiasis), is also of concern, as well as other known chronic diseases, drug consumption and heart murmur. Older people, especially those in nursing homes, have a particular risk of a bacterial infection (fever). Local findings Determined by the medical history or physical examination are evaluated and interpreted (see elsewhere in the MSD Manual). Other proposed findings include generalized lymphadenopathy, and rash. Generalized lymphadenopathy can in older children and young adults who suffer from acute mononucleosis, occur; This is usually accompanied by severe pharyngitis, malaise and hepatosplenomegaly. Primary HIV infection or secondary syphilis should be suspected in patients with generalized lymphadenopathy, sometimes accompanied by joint pain, rash, or both. HIV infection develops 2 to 6 weeks after exposure (although patients do not always talk about unprotected sexual contact or other risk factors). Secondary syphilis is preceded usually by a chancre, with systemic symptoms that are 4 to 10 wk. develop later. However, it may be that patients do not notice a chancre because it is painless and can be located out of sight in the rectum, vagina or oral cavity. Fever and rash have many infectious and drug causes. Petechial or purpuric rash is of particular interest; he may has meningococcal disease, Rocky Mountain Spotted Fever (especially when the palms or soles are affected) or, less frequently, to some viral infections (eg. B, dengue fever, hemorrhagic fever) out. Other suggestive lesions are the classic erythema migrans rash of Lyme disease, target lesions of Stevens-Johnson syndrome and painful, sensitive erythema of cellulite and other bacterial soft tissue infections. The possibility of delayed drug hypersensitivity (even after prolonged use) should be kept in mind. If no local results are available, have healthy people with acute fever and only nonspecific findings (z. B. malaise, generalized pain) is probably a self-limited viral illness, unless it is in the past exposure to infected contacts before (including new unprotected sexual contact), with disease carriers, or in an endemic area (including the most recent trip). Patients with significant underlying disorders have the higher risk of occult bacterial or parasitic infection. Patients who inject drugs and those with an artificial heart valve may be suffering from endocarditis. Immunocompromised patients are prone to infections caused by certain microorganisms (see Table: Some causes of acute fever). Drug fever (with or without rash) is a diagnosis of exclusion, which often requires to discontinue the drug. One difficulty is that if antibiotics are the cause, the disease is treated, can also cause fever. Sometimes an indication that fever and rash recurs after clinical improvement of the initial infection and without deterioration or recurrence of the original symptoms (eg. As in a patient who is being treated for pneumonia, fever but no cough, dyspnea or hypoxia ) beginnen.Tests tests depend on whether local results are available. If local results are available, tests are determined by clinical suspicion and clinical findings (see also elsewhere in the MSD Manual), as for the following: mononucleosis or HIV infection: serological tests Rocky Mountain Spotted Fever: biopsy of skin lesions to to confirm the diagnosis (acute serological tests are not helpful) Bakterielle- or fungal infection: blood cultures to detect possible infections of the bloodstream meningitis: Instant lumbar puncture and IV dexamethasone and antibiotics (head CT should be performed before lumbar puncture if in patients at risk of Gehirnprolaps present; IV dexamethasone and antibiotics should be administered immediately after administration of blood cultures and in front of the head CT) Specific diseases which are caused by exposure (for example, by contact, wearer or endemic areas:) tests for these diseases, esp. ondere peripheral blood smear for malarial If no local results are available to otherwise healthy patients and no serious disease is suspected, are usually observed at home without tests. In most cases, the symptoms can be eliminated quickly; the few that give cause for concern or develop local symptoms should be reassessed based on the new findings and tested when a serious illness is suspected in patients who do not have local findings, an examination is required. Patients with "red-flag findings" suggest sepsis, cultures need (urine and blood), chest x-ray and evaluation for metabolic disorders with measurement of serum electrolytes, glucose, BUN, creatinine, lactate and liver enzymes. A blood count is usually collected, but sensitivity and specificity for the diagnosis of severe bacterial infections is low. However, white blood cell count is prognostically important for immunsupprisierte patients (eg. As a low white blood cell count can be associated with a poor prognosis). Patients with certain underlying diseases should undergo tests, even if they have no local findings and do not seem to be seriously ill. Because of the risk and the devastating consequences of endocarditis are those antipyretics normally inject referred to hospital for various blood cultures and echocardiography. Patients using immunosuppressive need a blood count; if neutropenia is present, tests are introduced and chest x-ray is done, as well as cultures of blood, sputum, urine, stool, and all suspicious skin lesions. Because bacteremia and sepsis are common causes of fever in patients with neutropenia, empirical broad-spectrum IV antibiotics should be given immediately, without waiting for the culture results. Tests are often necessary (fever) in febrile elderly patients. Therapy Specific causes of fever are treated with anti-infective therapy; an empirical anti-infective therapy is required if the suspicion of a serious infection is high. Whether fever due to infection should be treated with antipyretics, is controversial. Experimental observations, but not clinical studies indicate that the host defense mechanisms are stimulated by fever. Fever should in certain patients, who are particularly vulnerable, even adults are treated with cardiac or pulmonary insufficiency or with dementia. Drugs that inhibit cyclooxygenase of the brain, reduce fever effectively: acetaminophen 650 to 1000 mg po q 6 h Ibuprofen 400 to 600 mg p.o. q 6 hours, the daily dose of paracetamol should not exceed 4 grams in order to avoid toxicity; Patients should be cautioned against simultaneously taking non-prescription cold or flu medications that contain acetaminophen. Other NSAIDs (eg., Aspirin, naproxen) are also effective antipyretics. Salicylates should not be used to treat fever in children with viral illnesses, because the use has been associated with Reye's syndrome. When the temperature is ? 41 ° C, further cooling measures (z. B. evaporative cooling with lukewarm water vapor, cooling blankets) should be used. Geriatrics basics: Fever In frail elderly, it is unlikely that the infection causes fever, and even when the temperature is increased by the infection, it can be lower than the standard definition of fever. Similarly, other inflammatory symptoms, such as focal pain, probably less known Frequently, a change in mental status or a decrease in daily body functions to be the only other initial manifestations of pneumonia or urinary tract infection. Despite their less severe manifestations of the disease, diefiebrigen older people are significantly more affected by a serious bacterial disease than younger adults feverish. In younger adults, the cause is often a respiratory infection or a urinary tract infection, but are in the elderly, skin and soft tissue infections the most common causes. Fokalbefunde be evaluated in younger patients. But unlike younger patients are elderly patients urinalysis, urine culture and a radiograph of the thoracic probably necessary blood cultures should be performed to rule out sepsis when sepsis is suspected or the vital signs are abnormal, the patient should be hospitalized become. Important Points Most fever in healthy people caused by viral respiratory or gastrointestinal infections. Guide Evaluation of local symptoms viewing the underlying chronic medical conditions, particularly those affecting the immune system.