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

cytokine Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autoc ...

s and

prostaglandin The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are deri ...

s 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. 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 A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving oscillations or twitching movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, fa ...

. Severe chills with violent shivering are called rigors.

Causes

Chills are commonly caused by inflammatory diseases, such as influenza. It is also common in urinary tract infections. Malaria is one of the common reasons for chills and rigors. In malaria, the

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...

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.

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{{General symptoms and signs Symptoms and signs Cold Thermoregulation fr:Frissonnement

Causes

See also

References

External links