Do you know that fever and inflammation are good signs?

It’s unpleasant when we have fever or inflammation, but do you know that these are signs that our body is doing its job?

Here is why and what should we know about these signs

  Fig: Thermometer showing body temperature

 

It is normal for our body temperature to fluctuate throughout the day, but generally in adults if body temperature is above 99.5°F(37.5°C), it is considered a fever [Balli,2021]

Fever is a sign that our body gives while fighting against pathogens, illness, or infections. We get a fever because our body is trying to kill a harmful virus or bacteria which can cause illness in our body [Britannica,2022]. Fever causes the release of White Blood Cells in our body, increases body metabolism, and stops unwanted, toxic, and unnecessary organisms from growing and increasing in numbers [Evans et al, 2015].

Which organ regulates our body temperature?

Our body temperature is regulated by Hypothalamus. It is situated in our brain and acts as our body’s smart control coordinating center.

The main function of the hypothalamus is to keep our body in a stable state called homeostasis (a condition in which all body systems are in balance, which is necessary for our bodies to exist and perform as intended).

          Fig: Position of Hypothalamus in brain

 

Why does fighting against infection causes fever?

A substance that can trigger fever (which causes fever) is called pyrogen. Pyrogen causes a release of Prostaglandin E2 (PGE2). PGE2 activates the hypothalamus, which generates a systemic response back to the rest of the body.[Radhi,2019] 

What is pyrogen?

Pyrogens are a class of chemicals that can cause fever. Endotoxins, which are lipopolysaccharides(LPS), are the most prevalent pyrogens, found in the membrane of Gram-negative bacteria like E.coli, Pseudomonas, Enterobacter, etc.

Pyrogens are mainly of two types Exogenous pyrogens and Endogenous pyrogens. Exogenous pyrogens are substances that are produced outside of the body. One of the potent exogenous pyrogens includes endotoxin from gram-negative bacteria. Exogenous pyrogen initiates fever through the induction of endogenous pyrogens from host cells. One of such endogenous pyrogens includes IL-1. Endogenous pyrogens can regulate the body temperature through diffusion to the hypothalamus thermo regulatory region. The hypothalamus releases several prostaglandins in response to pyrogen stimulation.  Pyrogens are also released from destroyed cells or our body.[Radhi,2019] 

What is PGE2 and from where it is secreted?

PGE2 is one of the major prostaglandins that is associated with hypothalamus thermostat regulation. PGE2 is released from the arachidonic acid pathway, a pathway by which fever regulator PGE2 and other inflammatory mediators are produced by pyrogen activity with phospholipids and COX-2 (Cyclooxygenase-2) usually in the brain or liver. This pathway is mediated by the enzymes cyclooxygenase-2 (COX-2), phospholipid A2( PLA2), and prostaglandin E2 synthase(PGE2 Synthase). These enzymes ultimately mediate the release of PGE2.[ Bernheim,1986]

In fever when WBC fights against various pathogens several tissues or cells get damaged which can cause inflammation.

What causes inflammation?

Inflammation occurs when any of our body tissues or cells get damaged or injured and those damaged cells release histamines (an organic nitrogenous compound), which cause the cell membranes to dilate[Britannica,2020].

Inflammation also occurs when our body releases chemicals from White Blood Cells (WBCs). These chemicals enter our body fluid (Blood, Lymph), or tissues to protect our body from different harmful invaders and protect from infections. There are several other causes of inflammation that can be indications of different internal infections or injuries.

 Fig:- Inflammation in the human body

So, from now on whenever you have a fever or inflammation you will know that your immune system is working perfectly. 

     But what if we are suffering from fever and inflammation for a long time? Is it really ok? when do we need to get alarmed regarding our fever & what Precautions need to be taken?

If we suffer from fever for more than 3 days or the fever keeps coming back for up to 14 days then it's important to see a doctor. Even if it’s a slight fever it may be a sign of a Serious issue, so, the doctor will Perform a few Physical exams and will ask about symptoms and medical history, to determine the cause of the fever,

 

When we should Seek Emergency Care?

 1. If having a severe headache

 2. Convulsions of Seizures

 3. Skin rash

 4. Mental confusion.

 5. Persistent vomiting.

 6. Abnormal Pain when urinating.

 7. Difficulty in breathing

 8. Chest Pain

 

 

Reference

1.  Balli S, Sharan S. Physiology, Fever. [Updated 2021 Aug 28]. In: Stat Pearls [Internet]. Treasure Island (FL): Stat Pearls Publishing; https://www.ncbi.nlm.nih.gov/books/NBK562334/
2.  Britannica, The Editors of Encyclopaedia. "fever". Encyclopedia Britannica,13 Aug. 2020, https://www.britannica.com/science/fever. Accessed 15 May 2022.
3.   Evans SS, Repasky EA, Fisher DT. Fever and the thermal regulation of immunity: the immune system feels the heat. Nat Rev Immunol. 2015;15(6):335-349. doi:10.1038/nri3843
4.    https://my.clevelandclinic.org/health/articles/22566-hypothalamus
5.  El-Radhi AS. Pathogenesis of Fever. Clinical Manual of Fever in Children. 2019;53-68.
6.  Bernheim HA. Is prostaglandin E2 involved in the pathogenesis of fever? Effects of interleukin-1 on the release of prostaglandins. Yale J Biol Med. 1986;59(2):151-158.
7.  Britannica, The Editors of Encyclopaedia. "histamine". Encyclopedia Britannica, 11 May. 2020, https://www.britannica.com/science/histamine. Accessed 15 May 2022.
8.  https://www.webmd.com/arthritis/about-inflammation
9. https://medlineplus.gov/ency/article/000821.htm
10. https://chemocare.com/chemotherapy/what-is-chemotherapy/the-immune-system.aspx
11. https://www.khanacademy.org/science/high-school-biology/hs-human-body-systems/hs-the-immune-system/a/hs-the-immune-system-review