UNIT 7 FEVER Flashcards
pyrexia
fever
Fever
elevation of body temperature caused by cytokine-induced elevation of hypothalamic set-point temperature
If fever above 41 degrees C
usually result of other activity such as dehydration, diabetes and other chemicals
Pyrogens
microorganisms and substances that cause a fever
Thermogenesis
mechanisms that raise temperature
Steps of fever production
- pyrogens enter
- set-point is elevated
- body responds to raise temperature (shivering, vasoconstriction (pallor), increased metabolism, HR)
- fever breaks (body at new temperature)
- reset set point to normal
- body responds to increase heat loss (sweating, lethargy, vasodilation)
- body returns to normal temperature
possible benefits of fever
- enhance mobilty/activity of WBC
- stimulate interferon production
- activate T cells
- inhibit growth of certain pathogens
fever may be described as
- intermittent
- remittent
- sustained
- relapsing
Intermittent fever
every 24h theres an increase in body temperature at night then it is brought back down
associated disease of intermittent fever
- abscesses = large areas of infected necrosis
- endocarditis = inflammation of inner lining of the heart
- sepsis
Remittent fever
never returns to normal, but osculations are similar to intermittent
associated problems with remittent fever
- upper respiratory tract viral infections
- mycoplasma infections
Sustained fever
not many osculations
- temperature remains above normal
eg. drug fever
Relapsing fever
- fever episodes each lasting several days
eg. TB, malaria, lyme disease, fungal infections
A 1 degree rise in body temperature produces a Heart Rate increase of?
15 bpm
4 stages of fever development
- prodromal peroid = initial feeling (fatigue, malaise, pain, aches)
- Chill = feeling cold, shivering
- Flush = warm and flushed skin
- Defervescense = onset of sweating (when fever breaks)
Delirium
metabolic rate increased during fever which increases use of oxygen, but there are not enough blood vessels to take oxygen to brain there for mismatch between supply and demand