FEVER

• Fever


  Pyrexia, occurs because heat-loss mechanisms are unable to keep pace with excessive heat production, resulting in an abnormal rise in body temperature
• Fever determination


  Based on several temperature readings at different times of the day compared with the usual value for that person at that time
• True fever


  Results from alteration in the hypothalamic set point
• Pyrogens


  Act as antigens, triggering immune system responses
• Pyrogens triggering fever


  The hypothalamus reacts to raise the set point and the body responds by producing and conserving heat. Several hours pass before the body temperature reaches the new set point
• Phases of fever


  • Chill phase
  • Plateau phase
  • Febrile phase
  • Afebrile phase
• Mild temperature elevations as high as 39°C (102.2°F) enhance the immune system of the body
• White blood cell production is stimulated during fever
• Increased temperature reduces the concentration of iron in the blood plasma, suppressing the growth of bacteria
• Fever fights viral infections by stimulating interferon, the natural virus-fighting substance of the body
• Fever serves a diagnostic purpose
• Purpose of fever patterns

  • Differ depending on the causative pyrogen. The increase or decrease in the pyrogen activity results in fever spikes and declines at different times of the day. The duration and degree of fever depend on the strength of the pyrogen and the ability of the individual to respond
• The term "fever of a known origin" or FUO refers to a fever with an undetermined cause
• Patterns of fever


  • Sustained
  • Intermittent
  • Remittent
  • Relapsing
• Hyperthermia


  Elevated body temperature related to the inability of the body to promote heat loss or reduce heat production
• Malignant hyperthermia is a hereditary condition of uncontrolled heat production that occurs when susceptible people receive certain anesthetic drugs
• Heatstroke


  Defined as a body temperature of 40°C (104°F) or more. It is a dangerous heat emergency with a high mortality rate
• Signs and symptoms of heatstroke include giddiness, confusion, delirium, excess thirst, nausea, muscle cramps, visual disturbances, and incontinence
• Vital signs during heatstroke include body temperature sometimes as high as 45°C (113°F), with an increase in heart rate (HR) and lowering of BP. Hot, dry skin is the most important sign
• Heat exhaustion


  Occurs when profuse diaphoresis results in excess water and electrolyte loss
• Symptoms of heatstroke


  • Confusion
  • Seizures
  • Loss of consciousness
  • Visual disturbances
  • Incontinence
• Vital signs during heatstroke

  Body temperature sometimes as high as 45 C (113 F), with an increase in heart rate (HR) and lowering of BP
• Hot, dry skin


  • The most important sign of heatstroke
• Heat exhaustion occurs when profuse diaphoresis results in excess water and electrolyte loss
• First aid for heat exhaustion

  Transporting the person to a cooler environment and restoring fluid and electrolyte balance
• Hypothermia occurs when heat loss during prolonged exposure to cold overwhelms the body's ability to produce heat
• Classification of hypothermia


  1. Unintentional - accidents

  2. Induced - surgery
• Accidental hypothermia usually develops gradually and goes unnoticed for several hours
• Assessment of hypothermia


  Temperature falls below 34.4 C (94 F), HR, respiratory rate, BP fall, skin becomes cyanotic
• Frostbite occurs when ice crystals form inside the cell, leading to permanent circulatory and tissue damage
• Interventions for frostbite


  Gradual warming measures, analgesia, protection of injured tissue
• Areas commonly affected by frostbite

  • Earlobes, tip of the nose, fingers, toes
• Thermometers can use Celsius or Fahrenheit scale
• Conversion of temperature scales

  1. To convert Fahrenheit to Celsius: 𝐶 = (𝐹 − 32) × 5/9

  2. To convert Celsius to Fahrenheit: 𝐹 = (9/5 × 𝐶) + 32
• Nursing interventions for patients with fever

  Obtain blood cultures, minimize heat production, maximize heat loss, satisfy metabolic rate requirements, promote patient comfort, identify febrile episode phases, initiate health teaching, control environmental temperature