From Wikipedia, the free encyclopedia
This article is about the physiological symptom. For other uses, see
Chill
.
Medical condition
Chills
is a feeling of coldness occurring during a high
fever
, but sometimes is also a common
symptom
which occurs alone in specific people. It occurs during fever due to the release of
cytokines
and
prostaglandins
as part of the
inflammatory response
, which increases the
set point
for body temperature in the
hypothalamus
. The increased set point causes the body
temperature
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 by
trembling
.
Severe chills with violent shivering are called
rigors
.
Pathophysiology
[
edit
]
Chills occur when the
hypothalamic
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, including
vasoconstriction
, and shivering ensue.
[2]
The person experiences this period as extreme cold, even though they might have an elevated body temperature 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]
Causes
[
edit
]
Chills are commonly caused by inflammatory diseases, such as
influenza
.
[3]
[
better source needed
]
Malaria
is one of the common reasons for chills and rigors. In malaria, the
parasites
enter the
liver
, grow there and then attack the red blood cells which causes rupture of these cells and release of a toxic substance
hemozoin
which causes chills recurring every 3 to 4 days. Sometimes they happen in specific people almost all the time, in a slight power, or it less commonly happens in a generally healthy person.
See also
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]
References
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External links
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Classification
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External resources
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