Fever

Question 1

Fever

Answer 1

Body temperature >103 F

- pyrexia

Question 2

What sets the thermoregulatory set point

Answer 2

Hypothalamus

Question 3

Difference between hyperthermia and fever

Answer 3

Hyperthermia: hot animal that wants to be cooler
Fever: hot animal that wants to be warmer

Question 4

Pyrogens

Answer 4

Reset thermoregulatory set point via local prostaglandins (PGE2)

Question 5

Exogenous pyrogens

Answer 5

• organisms
• antigens
• foreign substances
• drugs

Question 6

Endogenous pyrogens

Answer 6

Cytokines

- IL-1, IL-6, TNF

Question 7

Pyrogen process

Answer 7

• IL-1 secreted by phagocytes travels in blood to hypothalamus
• hypothalamus secretes prostaglandin, which resets hypothalamic thermostat
• nerve impulses cause shivering, higher metabolic rate, inhibition of sweating, and vasoconstriction
• these increase body temperature to the point set by the hypothalamic thermostat

Question 8

Endogenous pyrogens cause a _____ response

Answer 8

Non-specific response to infections, inflammatory and neoplastic diseases
- mediators of systemic inflammatory response

Question 9

Signs of hyperthermia

Answer 9

Demeanor: excited, agitated, distressed
Behavior: panting, vasodilation, sweating, cold-seeking
Body temp: up to 110 F or greater

Question 10

Signs of fever

Answer 10

Demeanor: lethargic, depressed, anorectic
Behavior: shivering/huddling, vasoconstriction, piloerection, heat-seeking
Body temp: rarely > 106-107 F

Question 11

Is infection the only cause of fever?

Answer 11

No

- could be inflammatory, immunologic, neoplastic, or drug-associated

Question 12

Fever as a protective mechanism

Answer 12

• enhances host immunity
• inhibits bacterial growth by reducing serum iron concentration
• contributes to neoplastic cell death
• encourages rest in affected animal

Question 13

Inflammation

Answer 13

Complex reaction in vascularized connective tissue

- leads to accumulation of fluid and WBCs in extravascular tissues

Question 14

Inflammation as a protective mechanism

Answer 14

• cause of cell injury: organism/toxin

- consequences of cell injury: dead cells/debris

Question 15

Harmful consequences of inflammation

Answer 15

• hypersensitivity
• chronic inflammatory disease
• immune-mediated disease
• scar tissue/fibrosis
• systemic inflammatory response*

Question 16

Inflammatory mediators

Answer 16

Entire inflammatory process is mediated by chemcials derived from plasma and cells

Question 17

5 cardinal signs of inflammation

Answer 17

• redness (rubor)
• swelling (tumor)
• heat (calor)
• pain (dolor)
• loss of function

Question 18

Types of inflammatory mediators

Answer 18

• vasoactive amines (histamine, serotonin)
• plasma proteases
• arachidonic acid metabolites (prostaglandins, leukotrienes)
• platelet activating factor
• nitric oxide
• oxygen-derived free radicals
• cytokines (IL-1, IL-6, TNFa)

Question 19

Inflammatory cytokines are produced by ____

Answer 19

Macrophages, lymphocytes, and EC

Question 20

Systemic inflammatory response

Answer 20

Cytokine mediated

• fever
• anorexia/cachexia
• lethargy/malaise
• acute phase proteins
• neutrophila
• anemia of chronic disease
• glucocorticoid release

Question 21

Lab results in patient with fever

Answer 21

• inflammatory or stress leukogram
• anemia of chronic disease
• mild hypoalbuminemia
• mild to marked hyperglobulinemia

Question 22

Physical cooling

Answer 22

Contraindicated

• stresses and distresses patient
• if needed, use NSAIDs instead