Pyrexia Flashcards
What is an intermittent fever?
Where the temperature returns to normal at least once every 24 hours
What kind of fever remains above normal with only minimal variations?
Sustained or continuous fever
What is a remittent fever?
Where the temperature does not return to normal and varies a few degrees in either direction
What is a recurring/relapsing fever?
Where there is one or more episodes of fever lasting as long as several days with one or more days of normal temperature
What is the central regulator of core body temperature?
Heat sensitive receptors located in the pre-optic area of the anterior hypothalamus
How many stages of fever are there?
Name them.
4
- Prodromal stage
- Chill stage
- Flush stage
- Defervescence stage
What occurs in the first stage of fever?
Non specific complaints such as headache, fatigue, general malaise, and aching
How does the nervous system control body temperature?
With elevations in core temperature the sympathetic nervous system is inhibited and when body temperature is below thermal set point the sympathetic nervous system is activated
How does the sympathetic nervous system increase body temperature?
Vasoconstriction of skin blood vessels and activation of the shivering centre and inhibition of sweating together with endocrine and behavioural responses to promote heat production
What occurs during the third stage of fever?
Cutaneous vasodilation occurs and the skin becomes warm and flushed leading to the last phase
What occurs during the last stage of fever?
Febrile response marked by the initiation of sweating
What should be the first step in managing fever?
Actively searching for the cause of the fever
Reassure that the fever is beneficial
Name some pyrogenic cytokines.
Pro-inflammatory cytokines: IL-1 IL-6 TNF-alpha Interferon
What modifies the responsiveness of thermosensitive neurone in illness?
Release of prostaglandin E2 caused by cytokine-receptor interactions in the pre-optic region of the anterior hypothalamus
What drugs inhibit the release of PGE2 and reduce fever?
NSAIDs
Aspirin
(both antipyretics)
What is CRP and what does it do?
C-reactive protein
Released by liver and promotes the immune system to destroy and inhibit microbial organisms
What can uncontrolled fever in young children cause?
Febrile seizures
Apart from fever what else can cause high temperature?
Hyperthermia
Drug-induced fever
Malignant hyperthermia
Neuroleptic malignant hyperthermia
What is hyperthermia?
High temperature not caused by pyrogens
A pathological increase in body temperature without change in set point of the hypothalamic regulatory centre
How should you manage hyperthermia?
Physical cooling
What drugs can induce fever?
Antihistamines
Tricyclic antidepressants
Cimetidine
Anticancer drugs
How do antihistamines and TCAs induce fever?
Impair heat dissipation
How does cimetidine induce fever?
Directly blocking receptors in the hypothalamus
How do anticancer drugs induce fever?
As a direct pyrogen
What is the best method of measuring temperature? (for both patient comfort and accuracy)
Tympanic temperature
What is the most accurate method of measuring temperature?
Rectally
What type of protein is CRP?
Acute phase protein (APP)
Name an endogenous antipyretic factor.
IL-10
