Fever

Question 1

What is the normal temperature

Answer 1

36.8+-/0.8 celcius

Question 2

What is fever

Answer 2

Rise in core temperature of more than 37.8

Question 3

What is fever regulated by

Answer 3

Hypothalamus in response to a pyrogen

Question 4

What is hyperthermia

Answer 4

Uncontrolled body temperature rise

Question 5

What is is hyperthermia not regulated by

Answer 5

Hypothalamus

Question 6

What is hyperpyrexia

Answer 6

Very high fever of more then 41.5 degree celcius and type of hyperthermia

Question 7

What is heat generated by

Answer 7

Metabolically active cells

Question 8

What is heat distributed by

Answer 8

The circulatory system

Question 9

What is lost heat to

Answer 9

Environment

Question 10

What is normal temperature regulated by

Answer 10

Hypothalamus

Question 11

What can the cause of hyperthermia be

Answer 11

Heat stroke syndrome
Diabetic ketoacidosis
Atropine, certain anaesthestics, antipychotic drugs 
Brain haemorrhage 
Hypothalamic stroke

Question 12

What is hyperthermia not regulated by

Answer 12

Hypothalamus

Question 13

What are pyrogens

Answer 13

Anything that causes a fever

Question 14

What are the types of pyrogens

Answer 14

Endogenous

Exogenous

Question 15

What are endogenous pyrogens

Answer 15

Host derived biologically active proteins (pyrogenic cytokines)

Question 16

What are exogenous pyrogens

Answer 16

Derives outside of the body and are mainly microbes

Question 17

Give examples of exogenous pyrogens

Answer 17

Bacterial ifnection and bacterial exotoxins

Viral infection and non human genetic material

Question 18

What happens when exogenous pyrogens enter the body

Answer 18

1. Act as TLR ligand
2. This acitvates the innate immunity
3. You get production of host pyrogenic cytokines

Question 19

How are endogenous pyrogens produced

Answer 19

Upon acitvation of tLR

Question 20

What are the endogenouc pyrogens that are produced

Answer 20

Cytokines of:
IL1
IL6
TNF

Question 21

What happens to the pyrogenic cytokines

Answer 21

Go into the systemic circulation and reach the endothalamic reticulum

Question 22

What happens when the pyrogenic cytokines reach the endothalamic reticulum

Answer 22

PGE2 (prostagland E2) increases

Question 23

Where does PGE2 increase at

Answer 23

Hypothalamic tissue

3rd cerebral ventricle

Question 24

When PGE2 increases how does it cause fever

Answer 24

Via CAMP neurotransmitter and vasomotor centre

Question 25

What are the other reason for cytokine production

Answer 25

Malignancy
Systemic vasculits
Autoimmune disease

Question 26

What is pyrexia of unknown origin

Answer 26

Fever or more than 37.8 celcuius
Duration of more than 21 days
Uncertain diagnosis after one week of invesitgation in hospital

Question 27

What is the 3 general classification of pyrexia of unkonw origin

Answer 27

Infection
Malignanct
Systemic rheuamtic disease

Question 28

Overall what happens to result in a fever

Answer 28

1. Exogenous pyrogens initiate fever by acting on the TLR of macrophages
2. Endogenous pyrogens i.e cytokines are produced as a result which ar IL1,IL6,TNF
3. These pyrogen cytokines are carried in the systemic circulation to the endothalamic reticulum
4. PGE2 increases in production and causes CAMP (neurotransmitter) to rise
5. This sets the thermostatic set point higher resulting in fever

Question 29

Which brain injury can cause damage to hypothalamus

Answer 29

Hypothalamic stroke
Haemmorhage
Status epilepticus

Question 30

Which drugs can reduce fever

Answer 30

Paracetomal
Aspirin
NSAIDs