Lec 3: Fever & Hyperthermia Flashcards
Criteria for fever
Elevated body temperature Increase in hypothalamic set point
Body temperature of > 41.5°C
Hyperpyrexia
Criteria for hyperthermia
Uncontrolled increased in boyd temperature exceeds body’s ability to lose heat
Normal core body temperature
36.5- 37.5 °C (97.7-99.5°F)
Methods for releasing heat
Exhalation
Sweat
Vasodilatation
Methods for heat production
Shivering
Increase liver emtabolism
Vasoconstriction
Behavioral adjustments (putting more clothes)
States that affect temperature
Menstruation (ldecrease)
Ovulation (increase)
Post prandial state (increase)
Pregnancy (increase)
Endocrinologic dysfunction
Increase in hypothalamic set point will lead to:
Vasoconstriction
Occurs in severe infeciton and most commony in CNS hemorrhages
Hyperpyrexia
Used to describe elevated temperature caused by abnormal hypothalamic function
Hypothalamic fever
Associated with a watm environment
Heatstroke
Common as a result of increased used of prescription psychotropic drugs and elicit drugs (e.g MAOI’s, Amphetamine, Tricyclic antidepresants, Cocaine)
Drug-induced hyperthermia
Caused by a rapid increase in intracellular Ca2+ levels in repsonse to Halothane, other inhalation anesthetics or succinylcholine. Often fatal.
Malignant hyperthermia
Characteristics of Neuroleptic Malignant syndrome
Lead pipe muscle rigidity
Extrapyramidal effects
Autonomic dysregulation
Hyperthermia
Distinguised by presence of diarrhea, tremor and myoclonus
Serotonin Syndrome
Any substance that causes fever
Pyrogens
Endogenous pyrogens
Cytokines: IL-1, TNF, IL-6, Ciliary neurotropic factor (CNTF)
One of the four receptors of PGE2 that is essential for fever
EP3
Principle in treatment of fever and hyperthermia
Treat the underlying cause
