What is Pyrexia? | Definition, Causes & Symptoms
Table of Contents
Show- FAQs
- Activities
Writing Prompts on the Definition, Causes, and Symptoms of Pyrexia
Read each scenario below and provide a brief written answer to each question. Use the given lesson as a reference.
Prompt 1
A 40-year-old woman was rushed into the emergency room in a nearby hospital. She has a continuous fever that started after returning from a one-month vacation in Hongkong. While in Hongkong, she developed knee pain from an accident, which migrated to multiple other joints. She also experienced mild nausea, decreased appetite, and chills for several weeks. Her temperature was around 107 degrees Fahrenheit. Her doctor pointed out that her rising temperature was due to her severe knee pain.
- Is the patient experiencing pyrexia?
- What could happen if her temperature rises to 107.6 degrees Fahrenheit and is left untreated?
Prompt 2
A 15-year-old boy complained about having rapid and shallow breathing and was later admitted to a medical facility. His breathing rate was about 20 breaths per minute, and his skin had a bluish-gray tint. He confessed to having traveled to Africa a couple of days ago but denied any sick contacts. His condition gradually worsened within a day of admission and he developed additional symptoms, including chest pain, shivering, vomiting, and a very high fever. To make things worse, his family, who traveled along with him, were also admitted for showing the same symptoms. Doctors found out that they have contracted a bacterial infection while in Africa.
- How do their bodies fight against these bacteria?
- Why do people shiver when having a fever?
Sample Answers
Prompt 1
- Yes, the patient's rise in body temperature is also referred to as pyrexia. This mechanism is developed by her immune system to fight the infection caused by her knee.
- Once her temperature rises above 107 degrees Fahrenheit and is left untreated, it will cause severe brain damage.
Prompt 2
- The hypothalamus changes the body's normal body temperature set point to hinder the growth and lower the number of bacteria.
- Shivering is a reaction caused by the movement of blood towards the internal core of the body. This reaction is part of the body's natural response to illness and helps in raising the temperature.
Medical Disclaimer: The information on this site is for your information only and is not a substitute for professional medical advice.
What are the symptoms of pyrexia?
Some common symptoms of pyrexia include: increased body temperature, irritability, dehydration, muscle aches, headaches, loss of appetite, weakness, chills, and sweating.
What causes pyrexia?
Some of the common causes of pyrexia include infection, anesthetic agents, side effects from medicinal and recreational drugs such as SSRIs, thyroid drugs, and MDMA.
What is a pyrexia temperature?
The typical temperature for pyrexia diagnosis is any body temperature above 100.4 degrees F. Hyperpyrexia is extremely elevator fever with temperature of 106 degrees F.
What is the difference between fever and pyrexia?
Fever is any elevation in body temperature above normal body temperature of 98.6 degrees F, whereas pyrexia is typically anything above 100.4 degrees F.
What does pyrexia mean?
Pyrexia is derived from Greek origin meaning presence of fever or to be feverish. The normal body temperature is 98.6F, and any temperature above 100.4F is considered a fever.
Table of Contents
ShowThe term pyrexia means to have an increased body temperature above normal body temperature. The word originated in mid 18th century Greece from the word purexis or 'to be feverish'. The normal body temperature of humans is 98.6 degrees Fahrenheit or 37 degrees Celsius. Any temperature above 100.4F/38 C in humans is diagnosed as pyrexia. It is typically caused by an illness, but there can be other causes as well for pyrexia in humans.
Symptoms
Some of the common signs and symptoms of pyrexia or fever include, but are not limited to:
- increase in bodily warmth
- dehydration
- irritability
- weakness or fatigue
- chills
- sweating
- headaches
- muscle aches and weakness
- generalized loss of appetite
The presence or absence of these symptoms depends on the cause of the fever as well. A very dangerous complication of pyrexia is febrile seizures (or presence of seizures due to fever). This typically occurs in children of ages 6 months up to 5 years. The occurrence of one febrile seizure increases the likelihood of another febrile seizure occurring within a year.
Some serious complications that can occur concurrently with fevers and require immediate medical attention are:
- presence of severe headaches
- stiff neck or inability to bend neck
- confusion or delirium
- continuous vomiting
- difficulty with breathing
- chest pain
- abdominal pain
- painful urination
- seizures
- sudden sensitivity of bright lights
- sudden and quickly worsening skin rash.
How It Occurs
A fever occurs as the hypothalamus increases or raises the set point or baseline temperature of the body. This occurs with the help of substances in the body known as cytokines. While the normal body temperature is 98.6 degrees Fahrenheit or 37 degrees Celsius, the temperature can range in 1 degree Fahrenheit or 0.5 degrees Celsius in either direction throughout the day due to many normal physiologic processes. While the body temperature is regulated by the hypothalamus in pyrexia, it is not under the regulation of the hypothalamus in a condition known as hyperthermia.
Why it Occurs
Pyrexia or fever can be caused by many different sources, both infectious and non-infectious such as: Explain the role of pyrexia in the human body.
A bacterial infection
A viral infection
Heat stroke or exhaustion
A cancerous tumor
Specific inflammatory conditions ie. rheumatoid arthritis
Antibiotics and medications used to treat high blood pressure or seizures
Some vaccines ie. DTaP or pneumococcal vaccine
If a cause cannot be identified, then it is known as fever of unknown origin.
In the case of an infectious source, a fever is helpful in that the rise in body temperature makes the body a less than ideal host for microorganisms causing them to die and allowing the immune response against them to prevail to heal the body of the source of the fever itself.
Treatment
Hypothermia is when the temperature of a body is too low below the normal body temperature of 98.6 degrees Fahrenheit/37 degrees Celsius. It can be caused by prolonged exposure to a cold environment, toxin exposure, metabolic issues, inability of the central nervous system to regulate temperature, and infections. Some treatment options for hypothermia include noninvasive options like applying warm washcloths, removal of cold or wet attire, and moving to a warmer environment. Additionally, more active forms of treatment include external heat application such as wrapping or insulating with warm blankets. Lastly, another active treatment involves heating the core within the body itself with methods such as warm IV fluids, breathing warm oxygen, and blood warming. Some factors that worsen the chances of hypothermia include very young or very old age, alcohol use, and the presence of complex medical conditions.
To unlock this lesson you must be a Study.com Member.
Create your account
Hyperthermia is a broad term used to describe any condition that results in inability of the body to adapt to heat in the external environment. It occurs specifically when the body temperature rises significantly above normal to 104F/ 38C. Hyperthermia can show up in many different forms throughout the body such as heat stress, heat fatigue, heat syncope, heat cramps, heat edema, heat rash, heat exhaustion, and heatstroke. If at any point these symptoms do not improve, then medical attention should be sought to prevent a heat stroke from occurring. Some things that can be done to ease these symptoms is moving to a shady area, resting by laying down or sitting down, keeping feet and knees elevated, and drinking lots of fluids especially water.
Hyperpyrexia is different from hyperthermia in that it is caused specifically by the presence of a fever. A fever is typically any body temperature that is above 100.4 degrees Fahrenheit. Hyperpyrexia occurs when body temperature increases to 106 degrees Fahrenheit specifically due to the presence of a fever. Some of the signs and symptoms of Hyperpyrexia include but are not limited to: temperature of above 106 degrees Fahrenheit, increased heart rate, rapid and shallow breathing, loss of consciousness, coma, confusion or delirium, muscle spasms and seizures. These are signs of a medical emergency and can lead to irreparable organ damage and death if medical attention is not sought.
Some causes of Hyperpyrexia include:
- infection
- anesthesia (hereditary)
- side effect of SSRIs, antipsychotic drugs, and MDMA.
- heat stroke
- thyroid storm
Treatments for Hyperpyrexia must address the increase in body temperature and the cause for it also. Along with using the treatment options mentioned for hyperthermia above, medical personnel must treat any underlying infections or combat the side effects of any possible drugs or medications by ceasing their use immediately. Anyone with a temperature above 103F must seek medical care immediately.
To unlock this lesson you must be a Study.com Member.
Create your account
Pyrexia is known as having a higher than normal body temperature, this includes a fever if the body's temperature rises above 100.4F/ 38C. Fevers can have many different sources of origin and the treatment varies with the cause of fever. The term fever must be distinguished from other medical conditions known as hyperthermia, Hyperpyrexia, and hypothermia.
To unlock this lesson you must be a Study.com Member.
Create your account
Video Transcript
Pyrexia: A Natural Immune Response
Have you ever wondered how we survived before the age of medicine? With so much controversy over vaccinations and the overuse of antibiotics causing resistant strains of superbugs, what did we do before we had medicine and access to healthcare?
Fortunately, we were designed with a complex mechanism of our own immune system called pyrexia. Pyrexia is a rise in the body's core temperature, otherwise known as a fever. It is a mechanism developed by the immune system to reduce the severity of illness by preventing bacteria and viruses from multiplying. This activation of the immune system has worked for centuries before medicine was invented. Most individuals view a fever as something that is bad or harmful, but it is a sign that our body is working in our favor to fight disease.
How Does Fever Work?
To understand what a fever is, we first need to discuss normal temperature. For example, a goat's core temperature is 105 degrees Fahrenheit, and a human's is 98.6 degrees Fahrenheit. I bet you're wondering how the heck they got a goat to put a thermometer in its mouth. Bad news: They probably had to resort to a rectal thermometer!
The temperature varies slightly depending on where in the body it was measured. For example, a rectal thermometer measures the body's internal core temperature by inserting a thermometer into the rectum.
An axillary temperature measures the temperature under the armpit, which tells the temperature on the surface of the skin. An oral temperature is taken by placing a thermometer under the tongue, which measures the temperature in the oral cavity (mouth).
So the temperature taken rectally (internally) will be higher and more accurate than if taken in the mouth or on the skin. Despite this, taking one's temperature rectally is far less common - it is certainly more convenient to take a temperature under the armpit or in someone's mouth as opposed to rectally at every doctor's appointment.
The Body's Internal Thermostat
The body's temperature actually fluctuates throughout the day and in response to activity and sleep patterns. The usual culprits - those not related to bodily injury or disease - are exercise, eating, medication, menstrual cycle, hot weather and humidity.
We have an internal thermostat called the hypothalamus, which is a small gland located in the brain. This gland functions as a part of the nervous system, sending signals out to the mechanisms that heat and cool the body. The hypothalamus responds to the presence of biochemical communicators called pyrogens, which are released into the bloodstream from injured body tissues or from the presence of disease-causing microorganisms.
The pyrogens cause the hypothalamus to increase the body temperature. This works to lower the amount of bacteria and virus in the body, because the high temperature makes it difficult for them to multiply and replicate. The heating process acts by shunting blood away from the extremities to the internal core of the body. This induces shivering that also raises temperature.
Treatment of Pyrexia
In most cases, fever does not need to be treated, because it is a sign that the body is working hard to defeat an infection or disease. Children usually have more fevers due to an immature immune system, and the American Academy of Pediatrics recommends easing uncomfortable symptoms as opposed to bringing a child's temperature back to a normal range. In much the same way, we don't go around medicating baby goats with fever; instead, we usually take a watch-and-see approach and let the fever run its course and fight off the bacteria or virus.
An antipyretic, such as over-the-counter ibuprofen or acetaminophen, may be given for pain or excessive crying related to a fever. Non-medical treatment for fevers include removing layers of clothing, lowering room temperature, applying a cool washcloth or soaking in a lukewarm bath.
Abnormal Symptoms of Pyrexia
There is a rare condition called hyperthermia when a fever is too high, usually higher than around 100 degrees Fahrenheit. If it reaches 107.6 degrees Fahrenheit, the rise in temperature can lead to brain damage. Most cases of hyperthermia are not caused by the hypothalamus. Rather, it occurs when someone is trapped in a hot car or exposed to otherwise excessive heat.
Some conditions, such as a tumor, may cause the hypothalamus to function abnormally and result in an elevated body temperature. Hyperthermia can be caused by drug and alcohol abuse as well as drug withdrawal, and it can even be a symptom of a stroke. With hyperthermia, some children may experience a febrile seizure, which is a benign type of seizure that is not related to a neurological condition such as epilepsy.
Lesson Summary
In this lesson, we discussed a normal body temperature, which is 98.6 degrees Fahrenheit in humans. We explored a unique immune response called pyrexia, which is a rise in the body's core temperature, due to a mechanism developed by the immune system to reduce the severity of illness by preventing bacteria and other viruses from multiplying.
Pyrexia is triggered by the hypothalamus, a small gland located in the brain and the body's internal thermostat that is activated by pyrogens in the bloodstream. Pyrogens are released into the bloodstream from injured body tissues or from the presence of disease cuasing microorganisms.
We learned about the different methods for taking a temperature - rectal, the base way to get true core temperature; oral, the most common; and axillary, under the armpit - and that treatment should be aimed at treating uncomfortable symptoms as opposed to lowering body temperature.
Some treatments include antipyretic, which are medication such as over-the-counter ibuprofen or acetaminophen. We finally learned about some of the abnormal conditions related to pyrexia, such as hyperthermia, a condition when a fever is too high, usually higher than around 100 degrees Fahrenheit.
Quick Review
- Pyrexia, or fever, is the body's way of fighting bacteria and viruses
- Pyrexia is a rise in the core temperature of the body and is triggered by the hypothalamus
- To determine pyrexia, body temperature can be taken three ways: anally, orally, or axillary
- Pyrexia can cause hyperthermia, which is a drastic increase in body temperature
Learning Outcomes
When you are finished, you should be able to:
- Explain what pyrexia is and its purpose in the body
- Recall the methods of determining the body's temperature
- List some of the ways to treat pyrexia
- Discuss some of the abnormal symptoms related to pyrexia
To unlock this lesson you must be a Study.com Member.
Create your account
Register to view this lesson
Unlock Your Education
See for yourself why 30 million people use Study.com
Become a Study.com member and start learning now.
Become a MemberAlready a member? Log In
BackResources created by teachers for teachers
I would definitely recommend Study.com to my colleagues. It’s like a teacher waved a magic wand and did the work for me. I feel like it’s a lifeline.