Fever Flashcards
what is a fever?
an elevation of body temperature above the normal daily variation
what does normal body temperature depend on?
the person, the body site where temp is measured, the time of the day
what is the temperature that defines a fever?
38 or higher
how is a fever involved in the immune system?
by making bacteria and viruses that cause infections less likely to survive
how is body temperature regulated?
thermoregulation
how does thermoregulation work?
where the thermoregulatory centre in the hypothalamus detects a change in core temperature it reacts by altering the level of sympathetic outflow to the cutaneous vessels on the skin, to regulate the core temperature via artery-venous anatomoses which constrict or dilate the vessels to induce/restrict heat loss from the skin
what happens to the sympathetic innervation when there is a high core temperature?
decreased, reducing the vasomotor tone in the AVAs. More blood flows to the skin to increase heat loss and reduce core temperature
what happens to the sympathetic innervation when there is a low core temperature?
increased, increasing the vasomotor tone in the AVAs - less blood flow to the apical skin to reduce heat loss and increase the core temp
what is the first-line analgesic for most forms of acute and chronic pain?
paracetamol
what are 3 common antipyretic?
paracetamol, ibuprofen, aspirin.
what is the mode of action of paracetamol?
it is a weak inhibitor of cyclo-oxygenase, which is the enzyme involved in prostaglandin metabolism. COX inhibition increases the pain threshold in the brain and reduces prostaglandin E2 (PGE2) concentrations in the thermoregulatory region of the hypothalamus which controls fever
when should paracetamol be reduced?
in people at risk of liver toxicity - particularly in IV infusion
what type of pain is ibuprofen regularly used for?
musculoskeletal inflammation
how do NSAIDs work?
inhibit COX enzyme to prevent prostaglandin synthesis) chemicals that promote pain, inflammation and fever
when should you avoid NSAIDS
severe renal impairment, heart failure, liver failure and known NSAID hypersensitivity
