FEVER [PYREXIA]

 

INTRODUCTION

• Fever is a common sign that can arise from many disorders.
• Fever is not itself a disease but the body's response to a disease.
• It is considered as one of the body's immune mechanism to attempt a neutralization of a perceived threat inside the body, be it bacterial or viral.
• A persistent high fever, though, represents an emergency.

DEFINITION

• Fever is an elevation of body temperature mediated by an increase of the hypothalamic heat regulatory set-point.

CONTROL MECHANISM OF BODY TEMPERATURE

• Human is "homoioterm" (has constant temperature). The Normal body temperature 37^o C within a narrow range of 1-1.5^o C.
• Circadian rhythm of body temperature - Early morning temperature is low and Highest level occurs at 4.00-6.00 PM
• Hypothalamic thermoregulatory center controls body temperature by
  • Peripheral cold and warm neuronal receptors
  • Temperature of blood circulating in the hypothalamus
• Heat generation
  • Increased cell metabolism
  • Muscle activity
  • Involuntary shivering
  • Heat conservation
  • Vasoconstriction
• Heat loss
  • Obligate heat loss (evaporation, radiation, convection, conduction)
  • Vasodilation
  • Sweating
• Physiological factors may increase body temperature
  • Physical activity (maximum 1.1^o C)
  • Digestion
  • Changes in environmental temperature
  • After ovulation in women
  • First three months of gestation
  • Exicement

MEASUREMENT

• The body temperature should be measured
  • at bed rest or physically inactive for 30 minutes before the temperature is taken
  • within one hour after a meal
  • prior intake of cold or hot foods
  • Before 6 years old - rectal or axillary
  • After 6 years old - oral temperature measurement

PATHOGENESIS

• Various infectious, immunologic or toxin-related agents (exogenous pyrogens) induced the production of endogenous pyrogens by host inflammatory cells.
• These endogenous pyrogens are cytokines, such as interleukins (IL-1b, IL-1a, IL-6), tumor necrosis factors (TNF-a, TNF-b), and interferon-a (INF).
• Endogenous pyrogenic cytokines directly stimulate to hypothalamus to produce prostoglandin E2, which then resets the temperature regulatory set point
• Endogenous pyrogens induce fever within 10-15 min. Whereas the febril response to exogenous pyrogens has a delayed onset requiring the synthesis and release of pyrogenic cytokines (60-90 min).

CLASSIFICATION

• A fever can be classified as
  • Low (oral reading of 99°F to 100.4°F [37.2°C to 38°C]),
  • Moderate (100.5°F to 104°F [38°C to 40°C]), or
  • High (above 104°F).
    Note -A fever greater than 106°F (41.1°C) causes unconsciousness and, if sustained, leads to permanent brain damage.
• A fever may also be classified as
  • Continuous fever/ Sustained 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, or typhus.
  • 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. An intermittent fever that fluctuates widely, typically producing chills and sweating, is called hectic, or septic, fever.
  • Remittent fever: Temperature remains above normal throughout the day and fluctuates more than 1 °C in 24 hours, e.g., infective endocarditis, brucellosis.
  • Pel-Ebstein fever/ Relapsing fever : A specific kind of fever consists of alternating acute episodes of fever and afebrile periods, e.g Hodgkin's lymphoma, certain bacteria in the genus Borrelia-
  • Undulant fever: refers to a gradual increase in temperature that stays high for a few days and then decreases gradually. E.g. Brucellosis (Mediterranean fever).
• Further classification involves duration — either
  • Brief - less than 3 weeks
  • Prolonged fevers - more than 3 weeks e.g. fever of unknown origin.

signs and symptoms

• Temperature greater than 100.4 F (38 C) in adults and children
• Shivering, shaking, and chills
• Aching muscles and joints or other body aches
• Headache
• Intermittent sweats or excessive sweating
• Rapid heart rate and/or palpitations
• Skin flushing or hot skin
• Feeling faint, dizzy, or lightheaded
• Eye pain or sore eyes
• Weakness
• Loss of appetite
• Fussiness (in children and toddlers)
• With very high temperatures (>104 F/40 C), convulsions, hallucinations, or confusion is possible.

ETIOLOGY

Most common cause infections of the upper respiratory tract.

• Respiratory infections
  • Common cold
  • Sinusitis
  • Pharyngitis: most frequent cause of fever in childhood.
  • Otitis media, mastoiditis
  • Pneumonia
  • Pulmonary tuberculosis
• Urinary tract infections
• Exanthemes
  • In the prodromal phase of exanthmatous diseases.
• Enteric infections
  • Salmonellosis
  • Ascariasis
  • Amebiazis
• Infections of the central neural system
  • Meningitis
  • Encephalitis
  • Poliomyelitis
• Infections of the liver and biliary tract
  • Infectious hepatitis
  • Cholangitis
  • Liver abscess
  • Granulamatous hepatitis due to sarcoidosis,tuberculosis,hystoplasmosis, brucellosis.
• Infectıons involving the heart
  • Rheumatic fever
  • Infective endocarditis
  • Myocarditis
• Systemic infections
  • Bacteremia
  • Infective endocarditis
  • Epidemic influenza
  • Enterovirus infections
  • Cytomegalovirus infection
  • Psittacosis
  • Epidemic myalgia
  • Malaria
  • Toxoplazmosis
  • Tuberculosis in nonpulmonary form
  • Brucellosis
• Abscesses, localized infections
  • Osteomyelitis
  • Intracranıal abscess
  • Lung abscess
  • Retropharyngeal abscess
  • Alveolar abscess
  • Perinephritic abscess
  • Appendiceal abscess
  • Pelvic abscess
  • Mediastinitis
  • Liver abscess
  • Subpherenic abscess
  • Spinal epidural infection
  • Purulant pericarditis
  • Empyema
  • Immunodeficiency diseases
  • Thrombophlebitis
• Neoplastic diseases
  • Leukemia
  • Hodkin's disease
  • Ewing tumor
  • Neuroblastoma with bone metastasis
• Dehydration
  • Especially in newborn and young infants
  • Hypertonic dehydration
  • Diabetes insipitus
• Drugs, immunization
  • Disappears after 72 hours (after the drug is stopped)
  • Immunuzation reactions
• Blood diseases
  • Hemolytic anemia, especially during a crisis
  • Transfusion reactions
• Hemorrhage
  • If bleeding occurs into a viscus or other body tissue in hemorhagic disorders
  • Intracranial hemorrhage in the newborn
  • Adrenal hemorrhage in the newborn
  • Hemorrhage into a tumor
• Miscallenous causes
  • Kawasaki disease
  • Familial mediterranean fever
  • Takayasu' arteritis
  • Virilizing adrenal hyperplasia
  • Inflammatory bowel disease (Crohn disease)

TREATMENT

• Generally, if the fever does not cause discomfort, the fever itself need not be treated.
• The following fever-reducing medications may be used-
  • Acetaminophen
  • İbuprofen
  • Naproxen
  • Aspirin - not be used for fever in children or adolescents
• An individual with a fever should be kept comfortable and not overdressed.
• Tepid water (85 F [30 C]) baths or sponging may help bring down a fever.
• Never immerse a person with a fever in cold/ice water.
• Never sponge a child or an adult with alcohol.
• Drink plenty of water and fluids, and avoid alcohol or caffeinated beverages, which can contribute to dehydration.
• A fan to circulate air or an open window may be helpful, as well as applying a cool damp washcloth to the forehead.

NURSING MANAGEMENT

• Hyperthermia related to increased metabolic rate
  • Take temperature every 1 to 4 hours to obtain an accurate core temperature. Identify route and record measurements. Use the same method each time temperature is taken.
  • Administer antipyretics, as prescribed and record effectiveness. Antipyretics act on hypothalamus to regulate temperature.
  • Use non-pharmacologic measures to reduce excessive fever, such as
    • removing sheets, blankets, and most clothing;
    • placing ice bags on axillae and groin; and
    • Sponging with tepid water. Tepid water is used because cold water increases shivering, thereby increasing metabolic rate and causing temperature to rise.
  • Use a hypothermia blanket if patient's temperature rises above 103° F (39.4° C). Monitor vital signs every 15 minutes for 1 hour and then as indicated. Temperatures that exceed 103 cannot be controlled with antipyretics alone
  • Turn hypothermia blanket off if shivering occurs. Shivering increases metabolic rate, increasing temperature.
  • Monitor heart rate and rhythm, blood pressure, respiratory rate, LOC and level of responsiveness, and capillary refill time every 1 to 4 hours to evaluate effectiveness of interventions and monitor for complications.
  • Determine patient's preferences for oral fluids and encourage patient to drink as much as possible, unless contraindicated. Monitor and record intake and output, and administer IV fluids, if indicated. Because insensible fluid loss increases by 10% for every 1.8° F (1°C) increase in temperature, patient must increase fluid intake to prevent dehydration.
• Impaired oral mucous membrane related to dehydration
  • Inspect patient's oral cavity every shift. Describe and document condition; report any change in status. Regular assessments can anticipate or alleviate problems.
  • Perform the prescribed treatment regimen, including administering IV or oral fluids, to improve the condition of patient's mucous membranes. Monitor progress, reporting favourable and adverse responses to the treatment regimen.
  • Provide supportive measures, as indicated:
    • Assist with oral hygiene before and after meals to promote a feeling of comfort and well-being.
    • Use a toothbrush with suction if patient can't spit out water to minimize risk of aspiration.
    • Provide mouthwash or gargles, as ordered, to increase patient comfort and maintain moisture in his mouth.
    • Lubricate patient's lips frequently with water-based lubricant to prevent cracked, irritated skin.
  • Instruct patient in oral hygiene practices, if necessary. to reduce discomfort, resulting in increased nutrition and hydration.
  • Tell patient to chew gum or suck on sugarless hard candy to stimulate salivation.
• Impaired comfort related to disturbed sleep pattern, inability to relax, and restlessness
  • Monitor pain level using scale 1 to 10. Assess vital signs during times of discomfort, including blood pressure, heart rate and rhythm, and respirations.
  • Assess sleeping patterns in response to discomfort.
  • Provide a quiet and relaxing atmosphere. Encourage active exercise to increase a feeling of well-being.
  • Provide pain medications as ordered.
  • Teach relaxation exercises and techniques to promote reduced pain levels, sleep, and reduce anxiety.
  • Teach medication administration and schedule to facilitate pain relief.
  • Teach massage therapy to caregiver to promote comfort. Refer to massage therapist to promote relaxation.
• Ineffective thermoregulation related to trauma or illness
  • Monitor patient's body temperature every 4 hours, or more often if indicated.
  • Monitor and record patient's neurologic status every 8 hours. Report any changes to the physician. Changes in LOC can result from tissue hypoxia related to altered tissue perfusion. Hyperthermia increases cerebral oedema and thus intracranial pressure (ICP); hypothermia depresses metabolic rate.
  • Monitor and record patient's heart rate and rhythm, blood pressure, and respiratory rate every 4 hours. Hyperthermia may create hypoxia by increasing oxygen demand, which results from increased tissue metabolism (metabolism increases 7% with each increase of 1° F [0.6° C]). This, in turn, results in faster breathing and a rising pulse rate.
  • Administer analgesics, antipyretics, and medications that prevent shivering, as prescribed. Monitor and record their effectiveness. Antipyretics help reduce fever. Shivering tends to retard the lowering of body temperature.
  • If patient develops excessive fever -
    • Remove blankets; place a loincloth over patient.
    • Apply ice bags to the axilla and groin.
    • Initiate a tepid water sponge bath.
    • Use a hypothermia blanket if temperature rises above 104 F
  • Maintain hydration through -
    • Monitor intake and output.
    • Administer parenteral fluids, as ordered.
    • Determine patient's fluid preference. Keep oral fluids at the bedside and encourage patient to drink.
  • Maintain the environmental temperature at a comfortable setting.
    • Ensure that all metal and plastic surfaces that come into contact with patient's body are covered.
    • Use or remove blankets as necessary for comfort.
    • Make sure that linens and clothing are clean and dry.
  • Instruct patient and family members about:
    • signs and symptoms of altered body temperature
    • precautionary measures to avoid hypothermia or hyperthermia
    • adherence to other aspects of health care management to help normalize patient's temperature