Chills is a feeling of coldness occurring during a high
fever
Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with Human body temperature, body temperature exceeding the normal range caused by an increase in the body's temperature Human body temperature#Fever, s ...
, but sometimes is also a common
symptom
Signs and symptoms are diagnostic indications of an illness, injury, or condition.
Signs are objective and externally observable; symptoms are a person's reported subjective experiences.
A sign for example may be a higher or lower temperature ...
which occurs alone in specific people. It occurs during fever due to the release of
cytokine
Cytokines () are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling.
Cytokines are produced by a broad range of cells, including immune cells like macrophages, B cell, B lymphocytes, T cell, T lymphocytes ...
s and
prostaglandins as part of the
inflammatory response, which increases the
set point for body temperature in the
hypothalamus
The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrin ...
. The increased set point causes the body
temperature
Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...
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.
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
Chills occur when the
hypothalamic temperature set point is suddenly elevated.
This could occur due to several causes, including tissue destruction, pyrogenic substances, or dehydration.
Due to the body temperature being below the new set point, body mechanisms of raising body temperature, including
vasoconstriction, and shivering ensue.
The person experiences this period as extreme cold, even though they might have a body temperature higher than normal.
As the body temperature rises and reaches the new set point, chills stop and the person feels neither hot nor cold.
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".
See also
*
Cold chill
*
Goose bumps
Goose bumps, goosebumps or goose pimples are the bumps on a person's skin at the base of body hairs which may involuntarily develop when a person is Tickling, tickled, cold or experiencing strong emotions such as fear, euphoria or sexual arousa ...
*
Night sweats
References
External links
{{General symptoms and signs
Symptoms and signs
Cold
Thermoregulation
fr:Frissonnement