Fever

Question 1

What is a normal temperature?

Answer 1

Normal temperature varies throughout the day and typically 36.8 ±0.8 ℃

Question 2

Definition of a fever

Answer 2

An elevation in core body temperature above the daily range for an individual”

Body temperature fluctuates throughout the day

Mackowiak et al. JAMA 1992:
Normal temperature = 36.8 ±0.8 ℃
Abnormal → Temperature ≥37.3℃ in the early morning
Abnormal → Temperature ≥37.8℃ overall

Question 3

Definition of fever

Answer 3

Regulated by the hypothalamus in response to pyrogens, resulting in a rise in core temperature ≥37.8℃

Question 4

Definition of hyperthermia

Answer 4

Not regulated by the hypothalamus and is an uncontrolled body temperature rise

Question 5

Causes of hyperthermia

Answer 5

Heat stroke syndromes
Metabolic diseases
Pharmacological agents
Neurological injury

Question 6

Causes of hyperthermia resulting from serotonin syndrome reactions?

Answer 6

Cocaine
NMDA (ecstasy)
Amphetamines
Tricyclic antidepressants (TCAs)
Selective serotonin reuptake inhibitors (SSRIs)
Monoamine oxidase inhibitors (MAOI) 
Lithium

Question 7

What are exogenous pyrogens?

Answer 7

EXOGENOUS PYROGENS are derived from outside of the host and mainly microbes and their products

Question 8

What are endogenous pyrogens?

Answer 8

ENODENOUS PYROGENS are host-derived biologically active proteins (pyrogenic cytokines)

Question 9

What is the definition of Pyrexia of Unknown Origin (PUO)?

Answer 9

The PUO definition has 3 criteria:

1. Fever ≥37.8℃ on several occasions
2. Duration of fever ≥21 days
3. Uncertain diagnosis after one week of investigation in hospital