Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MD1 SF3 - EXAM 2 > La fièvre > Flashcards

La fièvre Flashcards

1
Q

How much does temperature vary daily?

A

0.5C during the day according to the circadian rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the normal body temperature?

A

36.8C ± 0.4C

Men: 36.7C

Women: 36.9C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does temperature vary according to?

A

Moment in the day, sex, age, where temperature is taken, exercise, menstrual cycle, medication, digestion, certain diseases/illnesses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is “nadir” and “pic” de température?

A

Nadir: 37.2C buccale (lowest at 6h00)

Pic: 37.7C buccale (highest at 16h00-18h00)

La température rectale est d’environ 0.6C (0.4-0.6C) supérieure à la température buccale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What temperature do you need to have to have a fever?

A

Donc la fièvre (buccale) est toute température supérieure à 37.2C tôt le matin ou supérieure à 37.7oC à tout moment durant la journée

Une température rectale supérieure à 37.8oC le matin ou 38.3C à tout moment dans la journée = fièvre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the two main corporal temperatures?

A

Centrale (core): viscera and muscles

Peripheral (shell): skin and sub-cutaneous tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where can core temperature be measured?

A

Right atrium, esophagus, bladder, eardrum

  • La membrane tympanique est perfusée par une artère tributaire de celle qui irrigue l’hypothalamus
  • They used to think that rectal temperature was accurate but actually it is higher than core temperature
  • Buccal is reliable but easily altered by food/drinks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the advantages of infrared thermometers?

A
  • contact free —> minimize infection transmission
  • easy to use and disinfect
  • fast
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are some limitations of infrared thermometers?

A
  • Technique used can alter the measurement
  • Need to be < 1m away to take the temperature
  • Need quite specific conditions to assure that reading isn’t messed with (no direct sun, no hats, weather, etc.)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a fever?

A

Elevation of corporal temperature due to a signal from the hypothalamus in response to the presence of pyrogens

Circadian rhythm is preserved

Responds to treatment with antipyretics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is hyperthermia?

A

Elevation of corporal temperature NOT controlled by the hypothalamus (dépassement de la capacité du corps à perdre de la chaleur)

  • Circadian rhythm no longer detectable
  • Does not respond to antipyretics
  • Ex: coup de chaleur, hyperthyroïdie, prise de substances ou d’agents pharmacologiques qui interfèrent avec la thermorégulation (hyperthermie maligne, syndrome neuroleptique malin, syndrome sérotoninergique)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is hyperpyrexia?

A

Corporal temperature is very high… usually superior to 41.5C

  • Usually caused by a severe infection or brain haemorrhage
  • Can partially respond to antipyretics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is thermoregulation?

A

The ensemble of mechanisms that allow an organism to maintain their ideal temperature to best perform necessary biochemical rxns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is central temperature?

A

Balance between production de chaleur (thermogénèse) et la perte de chaleur (thermolyse)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What part of the brain controls corporal temperature?

A

Anterior hypothalamus (pre-optic region)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are pyrogens?

A

Substances that can modify temperature regulation (hypothalamus) and cause fever

17
Q

What are the two kinds of pyrogens?

A
  1. Exogen
  2. Cytokines (used to be called endogen)
18
Q

What are “pyrogènes exogènes”?

A

Substances étrangères à l’organisme (pathogens)

  • ex: bacteria, viruses, microbes, and their products
    • for example, bacterial endotoxins (LPS) from GN bacteria —> bind to TLR on leukocytes which activate cytokine production —> fever
19
Q

What are some examples of “pyrogènes exogènes”?

A
  1. La toxine TSST-1 du Staphylococcus aureus qui cause le syndrome du choc toxique
  2. Autres entérotoxines du Staphylococcus aureus
  3. Exotoxines du Streptococcus de groupe A
20
Q

What are “cytokines pyrogènes”?

A

Small proteins that regulate immunity, inflammation, and erythropoiesis —> usually not detectable in healthy pts

Certain cytokines are pyrogenic and are produced by cells after the activation of TLR (monocytes, macrophages, neutrophiles, lymphocytes)

Cytokines —> synthesis of PGE2 in the hypothalamus

  • en périphérie: c’est ce qui cause les myalgies et les arthralgies chez les personnes fébriles
21
Q

What are some examples of “cytokines pyrogènes”?

A
  1. Interleukin-1 (IL-1)
  2. Interleukin-6 (IL-6)
  3. Tumor necrosis factor-alpha (TNF-⍺)
  4. Ciliary neurotropic factor (CNF)
  5. Interferon-gamma (IFN-ɣ)
22
Q

What is the pathogenesis of fever? (2 ways)

A

two ways:

  1. exogenic pyrogen —> TLR on WBCs —> produce cytokines —> systemic circulation to epithelium of hypothalamus —> production of PGE2 —> increase temperature —> neurons in vasomotor center —> production and conservation of heat by different organs/muscles —> fever
  2. exogenic pyrogen —> direct action on TLR —> systemic circulation to epithelium of hypothalamus —> production of PGE2 —> increase temperature —> neurons in vasomotor center —> production and conservation of heat by different organs/muscles —> fever
23
Q

Where else does the thermoregulation center send signals?

A

Cerebral cortex —> change positioning and behaviour to favour production/conservation of heat

Produce heat: contract muscles

Conserve heat: move to warmer area, more clothing, huddle together, change posture

24
Q

What is the pathogenesis of lowering temperature?

A

exogenic pyrogens disappear —> cytokines no longer produced —> no more PGE2 —> thermoregulation center “sets” temp back to normal —> stop production of heat and increase processes that help you lose heat

How: Peripheral vasodilation —> inc. heat loss, sweating, taking off clothing, move to colder place, open window/AC

25
Q

What is the “réponse de phase aiguë”?

A

Différents stimuli peuvent induire une réponse de phase aiguë qui a pour but d’optimiser les défenses de l’organisme en modulant l’inflammation et la réparation des tissus

  • Infection, trauma, cancer, brûlure, infarctus, arthropathies microcristallines et autres atteintes inflammatoires, accouchement, exercice important

Stimulates hepatocytes to produce proteins (IL-6 = principal stimulator)

26
Q

What are PCR and PSAa?

A

PCR: protéine-C réactive —> binds to necrotic/damaged cells to eliminate them

PSAa: protéine sérum-amyloïde A —> increases chemiotactism of phagocytes

27
Q

Why are fevers so physically demanding?

A

Increase O2 consumption

Increase caloric and fluid needs (dehydration)

For each 1C of temperature increase above 37C:

  • O2 consumption increases by 13%
  • HR increases by 4.4 BPM

Can cause psychological stress —> dim. brain function in fragile/older pts

Much harder to handle in pts with chronic illnesses or older in age

28
Q

Fevers put your body into a catabolic state… how?

A

Dim. in glucose availability

Anorexia and lethargy —> dim. in food intake Increase muscle catabolism due to certain cytokines

Weight loss

29
Q

What are the clinical manifestations of fevers? (7+1)

A
  1. frissons/tremblements
  2. malaise
  3. faibless généralisée
  4. céphalées myalgies
  5. arthralgies
  6. perte d’appétit
  7. déshydration

In children —> febrile seizures (usually benign)

30
Q

What is an FUO?

A

Fever of unknown origin —> term often used even if not FUO according to dx criteria

  • Fever > 38.3C on multiple occasions, for longer than 3 weeks
  • Uncertain dx after week of investigation in the hospital but has been modified recently due to reflect modern medicine:
    • 3 visits to doctor or 3 days in hospital
31
Q

What is a “fièvre factice”?

A

Produced by patient using various strategies

Must be considered in ddx

32
Q

What questions do you ask a febrile pt? (4 main)

A
  1. Depuis combien de temps s’est installée la fièvre?
  2. La fièvre a été mesurée à combien et comment?
  3. Quand survient la fièvre?
  4. Est-ce un premier épisode?
33
Q

What epidemiological questions do you ask fever pts? (8)

A
  1. Lieu de naissance Lieu où le patient habite
  2. Voyages récents ou passés
  3. Travail
  4. Loisirs
  5. Alimentation
  6. Exposition à des animaux
  7. Contacts infectieux adultes et enfants (en contact avec gens qui ont sx similaires à la votre)
  8. Expositions sexuelles
34
Q

Approche du patient fébrile:

A

Investigations depending on clinical presentation

“Bilan septique” usually done when nothing obvious from initial questioning

35
Q

What is a “bilan septique”?

A

Formule sanguine complète, hémocultures x2, culture urine, culture d’autres sites, RdRx des poumons

36
Q

Why are fevers treated?

A
  1. make more comfortable
  2. diminish oxygen demand in pts with pre-existing CV or pulmonary conditions
  3. avoid mental deterioration in fragile or older patients

On essaie d’éviter les grands écarts de température qui sont inconfortables

  • frissons et frilosité lorsque la température monte
  • sudations profuses lorsque la température baisse
37
Q

What the 3 main antipyrétiques that can treat fevers?

A
  1. Acetaminophen
  2. Aspirin and other anti-inflammatories
  3. Corticosteroids (not used as antipyrétiques but can diminish fever)
38
Q

What are some secondary effects of antipyretics?

A

Acetaminophen: overdose —> hepatitis rx

AINS: epigastric pain, ulcers in upper GI tract

Aspirin: Reye’s syndrome in children and adolescents

  • Associated with aspirin usage to treat viral infections
  • Encephalopathy and deterioration of “bilan hépatique” (stéatose microvésiculaire)
39
Q

What are some complications of fevers? (4 main ones)

A

Febrile seizures —> mostly b/w 6mths-5yrs… usually benign

Aggravation of CV/pulmonary disease

Development of organic brain syndrome

Hyperpyrexia (41.5C) —> cerebral lesions and cardiac arrhythmias

MD1 SF3 - EXAM 2 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions