Febrile Illness: Clinical Manifestations

Heat Stroke and Febrile

• Heat stroke: a life-threatening condition with a body temperature greater than 41°C (106°F)
• Clinical manifestations of febrile (fever):
  • Onset (cold/chill phase): • Increased heart rate • Increased respiratory rate and depth • Shivering • Pallid (pale), cold skin • Complaints of feeling cold • Cyanotic nail beds • “Gooseflesh” appearance of the skin • Cessation of sweating
  • Course (plateau phase): • Absence of chills • Skin that feels warm • Photosensitivity • Glassy-eyed appearance • Increased pulse and RR • Increased thirst • Mild to severe dehydration • Drowsiness, restlessness, delirium, convulsions • Herpetic lesions of the mouth (ulcers) • Loss of appetite (if the fever is prolonged) • Malaise, weakness, aching muscle
  • Defervescence (fever abatement/flush phase): • Skin that appears flushed and feels warm • Sweating • Decreased shivering • Possible dehydration

Hypothermia

• Hypothermia: a core body temperature below the lower limit of normal
• Physiological mechanisms of hypothermia: • Excessive heat loss • Inadequate heat production to counteract heat loss • Impaired hypothalamic thermoregulation
• Clinical manifestations of hypothermia: • Decreased body temperature, pulse, respiration • Severe shivering (initially) • Feelings of cold and chills • Pale, cool, waxy skin • Frostbite (discolored, blistered nose, fingers, toes) • Hypotension • Decreased urinary output • Lack of muscle coordination • Disorientation • Drowsiness progressing to coma

Nursing Interventions

• For clients with fever: • None mentioned
• For clients with hypothermia: • Provide a warm environment • Provide dry clothing • Apply warm blankets • Keep limbs close to body • Cover the client’s scalp with a cap or turban • Supply warm oral or intravenous fluid • Apply warming pads

Assessing Body Temperature

• Common sites for measuring body temperature: • Oral • Rectal • Axillary • Tympanic membrane • Skin/temporal artery
• Advantages and disadvantages of sites used for body temperature measurement: • Oral:
  • Accessible and convenient
  • Disadvantages: thermometers can break if bitten, inaccurate if client has just ingested hot or cold food or fluid or smoked, could injure the mouth following oral surgery • Rectal:
  • Reliable measurement
  • Disadvantages: inconvenient and more unpleasant for client, difficult for client who cannot turn to the side, could injure the rectum, presence of stool may interfere with thermometer placement • Axillary:
  • Safe and noninvasive
  • Disadvantages: thermometer may need to be left in place for a long time to obtain an accurate measurement • Tympanic membrane:
  • Readily accessible, reflects the core temperature, very fast
  • Disadvantages: can be uncomfortable, involves risk of injuring the membrane if the probe is inserted too far, repeated measurements may vary

Factors Affecting Body Temperature

• 5 factors that affect body temperature: • Progesterone: raises body temperature by about 0.3°C to 0.6°C above basal temperature • Stress stimulation: stimulation of the sympathetic nervous system can increase the production of epinephrine and norepinephrine, thereby increasing metabolic activity and heat production • Environment: extremes in the environment temperature can affect a person’s temperature regulatory system • Basal metabolic rate (BMR): the rate of energy utilization in the body required to maintain essential activities such as breathing • Muscle activity: including shivering, increases the metabolic rate

Alterations in Body Temperature

• Normal range: 36°C – 37.2°C
• Abnormal alterations in body temperature: • Pyrexia/hyperthermia/fever/febrile: 38°C • Hyperpyrexia: 41°C • Hypothermia: less than 36°C

Types of Fever

• 4 common types of fever: • Intermittent fever: a body temperature that alternates at regular intervals between periods of fever and periods of normal or subnormal temperature • Remittent fever: the occurrence of a wide range of temperature fluctuations, more than 2°C (3.6°F) over a 24-hour period, all of which are above normal • Relapsing fever: the occurrence of short febrile periods of a few days interspersed with periods of 1 or 2 days of normal temperature • Constant fever: a state in which the body temperature fluctuates minimally but always remains above normal • Fever spike: a temperature that rises to fever level rapidly following a normal temperature and then returns to normal temperature within a few hours • Heat exhaustion: a condition that is the result of excessive heat and dehydration

Regulation of Body Temperature

• The system that regulates body temperature: • Sensors in the periphery and in the core • An integrator in the hypothalamus
• Heat loss from the body: • Radiation: the transfer of heat from the surface of one object to the surface of another without contact between two objects, mostly in the form of infrared rays • Conduction: the transfer of heat from one molecule to a molecule of lower temperature • Convection: the dispersion of heat by air currents • Evaporation: continuous vaporization of moisture from the respiratory tract and from the mucosa of the mouth and from the skin
  • Insensible water loss: continuous and unnoticed water loss
  • Insensible heat loss: accompanying heat loss