Physiology of fever

Question 1

What is a fever?

Answer 1

a physiological response normally to an infection, initiated as a part of an immune response

Question 2

What temperature is considered a fever?

Answer 2

greater than 37.8*C

Question 3

What are the medical terms for fever?

Answer 3

pyrexia or febrile illness (the common term used in paediatrics)

Question 4

What does the immune system do?

Answer 4

protects us from foreign invaders

Question 5

What do white blood cells do?

Answer 5

aimed to protect from antigens (any foreign substance that creates an immune response)- macrophages are a type of white blood cell that carry out phagocytosis

Question 6

What are cytokines?

Answer 6

chemical messengers released by WBCs that influence the immune system response to assist with fighting infections

Question 7

What type of cytokine is responsible for generating a fever?

Answer 7

pyrogen

Question 8

What part of the brain is responsible for temperature regulation?

Answer 8

hypothalamus

Question 9

How do pyrogenic cytokines influence the hypothalamus?

Answer 9

stimulate it to release prostaglandin, which is responsible for raising body temperature

Question 10

How does prostaglandin work?

Answer 10

mechanism not fully understood- believed to cause vasoconstriction, triggers shivering response

Question 11

What is aggressive shivering known as?

Answer 11

rigors

Question 12

What are some pros of a fever?

Answer 12

• raised temp stimulates specific immune system function (works faster at higher temp) & increase WBC production
• higher temperature inhibits growth of bacteria/ pathogens or harms them- denaturation

Question 13

What are some cons of a fever?

Answer 13

• a 2*C rise in temp = 20% extra energy requirement
• causes discomfort & pain
• can lead to serious levels of dehydration
• affects & damages normal processes of the body, including all enzyme reactions- denaturation
• more rarely, it can lead to organ damage if very high for a prolonged period