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Microbiology- Bacteriology
Fever (T Pierce)
25
Medical
Professional
08/25/2009

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Cards

Term
Average body temperature
Definition

36.8 C (97.8 F)

can creep up 1 degree F in afternoon

Term
Effect of age on body temperature
Definition
increase age means lower body temp.
Term
Effect of ovulation on body temperature
Definition
increases temp. by 0.5
Term
Compare rectal temperature to oral and core temp.
Definition
  • rectal 0.4 degrees higher than oral
  • rectal 0.2 degrees higher than core
Term
Location of temperature sensor in hypothalamus
Definition

preoptic area in anterior hypothalamus

Term
States that alter oral temp
Definition
  • smoking- higher
  • mastication- higher
  • increase resp. rate (tachypenia)- lower
Term
Path of temp regulation
Definition
  1. inputes from peripheral warm and cold receptors to the anterior hypothalmus
  2. when increase firing, signal set to posterior hypothalamus (regulator/set point)
  3. midbrain sends signals that can cause
    1. shivering
    2. via symp. chain, affect vasomotor tone (vasodilation) and sweating
Term
Effect of hyperthermia or hypothermia on set point and temperature
Definition
  • each alters temperature, but set point stays the same

IN FEVER, the SET POINT CHANGES.

Term
Define fever
Definition
  • state of altered core temperature often associated with defensive responses of multicellular organism to invasion by matter recognized by host as pathogenic/alien
Term
Role of endogenous pyrogens in fever
Definition
  • stimulated to be released by exogenous pyrogens
  • endogenous pyrogens then stimulated to cross blood brain barrier
Term
char. of endogenous pyrogens
Definition
  • synthesized not stored
  • mononuclear phagocytic cells
  • cross the BBB
  • nanogram quantities of:
    • IL-1
    • TNF alpha
    • IFN gamma
Term
Sources of IL-1
Definition
  • mononuclear phagocytes (main source)
  • myelomonocytic leukemia cells
  • renal cell carcinoma cells
  • Langerhans cells
  • keratinocytes
Term
Process of fever formation
Definition
  1. exogenous pyrogens stimulated
  2. mononuclear phagocytes to release
  3. IL-1 which crosses the
  4. BBB to stimulate
  5. the preoptic area of anterior hypothalamus to release
  6. arachodonic acid which stimulates production of
  7. thromboxanges and PGE2 which act by increasing
  8. cAMP within the cell which stimulate
  9. posterior hypothalmus (thermostate) to stimulate the
  10. vasomotor center which will act via
  11. sympathetic efferents to
  12. vasoconstrict bv's leading to
  13. FEVER
Term
acute phase response to invaders
Definition
  • definition- generalized, coordinated, nonspecific reaction in response to microbial invader that is:
    • thermoregulatory
    • anti infective
    • anti inflam.
    • metabolic
    • procoagulant
Term
thermoreg. component of acute phase response
Definition
  • fever rarely go above 41 degrees C
    • cryogenic neurons increase firing to bring down temp.
      • ex: ACTH, MSH
Term
Anti infective component of acute phase response
Definition
  • pro-inflam. cytokines (IL, TNF alpha), ICAM, phagocytic cells, complement
Term
anti inflam. component of acute phase response
Definition
  • anti inflam cytokines (IL-4, IL-10)
  • ACTH
  • haptoglobin
Term
procoagulant part of acute phase response
Definition
localize infection by preventing spread in the blood
Term
metabolic component of acute phase response
Definition
  • cortisol increases
  • increase gluconeogenesis
  • increase catecholamines
  • increase lipolysis
Term
Rationale of antipyretic therapy
Definition
  • relieve discomfort
  • reduce mortality
  • prevent febrile seizures (no real difference seen in studies)
  • reduce cognitive impairment (no data)
  • improve outcome of patients with stroke or brain injury
  • reduce metabolic demands in patients with severe CV disease (prevent shivering)

 

Term
disadvantages of antipyretic therapy
Definition
  • external cooling can cause coronary vasospasm through cold pressor response
  • reduction in heat shock proteins
  • adverse effects on antiperetics

NO EFFECT IN SEPSIS

Term
Benefits of fever
Definition
  • increase Ig syn.
  • T cell activation
  • increase cytokine production
  • increase NK cell activity
  • increase phagocytic cell activity
  • suppress microbial growth
  • reduce viral replication
Term
What would classify a patient with fever of unknown origin
Definition
  • illness of more than three weaks duration
  • fever greater than 38.4 on several occasions
  • diagnosis uncertain after one week of study in the hospital
Term
Potential causes of FUO
Definition
  • infection
  • neoplasms
  • CT diseases
  • miscellaneous
Term
Treatment of FUO
Definition
  • uncommon manifestation of common diseases are more common than uncommon diseases
  • observe over time
  • avoid therapeutic trials
  • review prescribed and social drug intake
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