Fever as altered thermoregulatory setpoint

Fever is characterized by activation of effector mechanisms to achieve and maintain a temperature higher than normal. Thus it should be distinguished from hyperthermia, in which the set-point is normal but effector mechanisms have failed to keep body temperature at the set-point. In fever, if the body temperature is below the elevated set-point, heat-conserving mechanisms will be activated as shown in Fig 1. Thus, for example, a patient with a fever may have a set-point of 39 °C

and a body temperature of 38 °C; such a patient will tend to feel cold (behavioral thermoregulation), have peripheral vasoconstriction, and may shiver. Therefore body temperature will tend to rise towards the new elevated set-point. In fever the set-point frequently varies in a cyclical fashion; thus as it falls, the actual body temperature may exceed the set-point and the patient will tend to feel hot, vasodilate, and sweat in order to lose heat.

Fig. 1 Changes in actual and set-point temperatures during a febrile episode.

Was this article helpful?

0 0
Sleep Apnea

Sleep Apnea

Have You Been Told Over And Over Again That You Snore A Lot, But You Choose To Ignore It? Have you been experiencing lack of sleep at night and find yourself waking up in the wee hours of the morning to find yourself gasping for air?

Get My Free Ebook


Post a comment