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| Chills | |
|---|---|
| Specialty | Infectious disease |
Chills is a feeling of coldness occurring during a highfever, but sometimes is also a commonsymptom which occurs alone in specific people. It occurs during fever due to the release ofcytokines andprostaglandins as part of theinflammatory response, which increases theset point for body temperature in thehypothalamus. The increased set point causes the bodytemperature to rise (pyrexia), but also makes the patient feel cold or chills until the new set point is reached.Shivering also occurs along with chills because the patient's body produces heat during muscle contraction in a physiological attempt to increase body temperature to the new set point.[1] When it does not accompany a high fever, it is normally a light chill.
Sometimes a chill of medium power and short duration may occur during a scare, especially in scares of fear, commonly interpreted like or confused bytrembling.
Severe chills with violent shivering are calledrigors.
Chills occur when thehypothalamic temperature set point is suddenly elevated.[2] This could occur due to several causes, including tissue destruction, pyrogenic substances, or dehydration.[2] Due to the body temperature being below the new set point, body mechanisms of raising body temperature, includingvasoconstriction, and shivering ensue.[2] The person experiences this period as extreme cold, even though they might have a body temperature higher than normal.[2] As the body temperature rises and reaches the new set point, chills stop and the person feels neither hot nor cold.[2] If the factor causing the high temperature is then removed, the hypothalamic set point decreases, but the body temperature is still higher than it. This then triggers the body cooling mechanisms to reduce the body temperature to the new set point, and is experienced as severe sweating, and hot skin due to vasodilation. This phase of the febrile state is known as the "crisis", or the "flush".[2]