What constitutes a dangerous fever. How high does a fever need to be to warrant concern. When should you seek medical attention for a fever. What are the signs of a potentially dangerous fever.

The Nature and Causes of Fever

Fever is a common symptom that often indicates the body’s response to an underlying condition. It’s not an illness in itself, but rather a sign that the immune system is actively fighting against invaders. Understanding the nature of fever can help individuals make informed decisions about when to seek medical attention.

What exactly causes a fever? Fever typically occurs when the body’s internal thermostat, located in the hypothalamus, raises the body temperature above its normal range. This increase in temperature can be triggered by various factors:

• Viral infections (e.g., flu, common cold)
• Bacterial infections (e.g., pneumonia, urinary tract infections)
• Inflammatory conditions (e.g., rheumatoid arthritis, inflammatory bowel disease)
• Heat-related illnesses (e.g., heatstroke)
• Certain medications or illegal drugs
• Some types of cancer
• Autoimmune disorders

Is fever always a cause for concern? Not necessarily. In many cases, a low-grade fever is actually beneficial, as it indicates that the body’s defense mechanisms are working properly. However, understanding when a fever becomes dangerous is crucial for proper health management.

Normal Body Temperature and Fever Thresholds

To comprehend what constitutes a dangerous fever, it’s essential to first understand normal body temperature ranges and how they fluctuate.

What is considered a normal body temperature? The average body temperature is typically cited as 98.6°F (37°C), but it’s important to note that normal can vary slightly from person to person. Generally, a normal temperature range falls between 97.7°F (36.5°C) and 99.5°F (37.5°C).

When does a temperature become classified as a fever? A temperature above 99.5°F (37.5°C) is generally considered a fever in both adults and children. However, the severity of a fever is often categorized as follows:

• Low-grade fever: 100.4°F (38°C) to 102.2°F (39°C)
• Moderate-grade fever: 102.2°F (39°C) to 104°F (40°C)
• High-grade fever: Above 104°F (40°C)

Are there factors that can affect body temperature without indicating a fever? Yes, several factors can influence body temperature without necessarily indicating an illness:

• Time of day (temperatures tend to be higher in the evening)
• Physical activity
• Hormonal changes (e.g., menstruation)
• Environmental conditions (high heat and humidity)
• Certain medications

Recognizing Dangerous Fever Levels

While a mild fever is often not a cause for immediate concern, it’s crucial to recognize when a fever becomes potentially dangerous.

At what point does a fever become dangerous? Generally, a fever is considered dangerous when it reaches 103°F (39.4°C) or higher in adults. For children, the threshold may be lower, and medical attention should be sought for temperatures above 102°F (38.9°C), especially in infants and toddlers.

Are there specific symptoms that indicate a dangerous fever? Yes, certain symptoms accompanying a fever can signal a more serious condition:

• Severe headache
• Stiff neck
• Confusion or altered mental state
• Persistent vomiting
• Difficulty breathing
• Seizures
• Severe abdominal pain
• Unusual skin rashes or bruising

Should the approach to fever differ for children and adults? Absolutely. Children, especially infants and young toddlers, are more vulnerable to the effects of high fevers. Parents should be particularly vigilant and consider seeking medical attention sooner for a child with a fever than they might for an adult.

Managing Fevers at Home

For mild to moderate fevers, home management can often be effective. Understanding proper care techniques can help alleviate discomfort and support the body’s natural healing processes.

What are some effective ways to manage a fever at home? Here are several strategies:

1. Rest: Allow the body to conserve energy for fighting the infection.
2. Hydration: Drink plenty of fluids to prevent dehydration.
3. Cool compresses: Apply a cool, damp cloth to the forehead or wrists.
4. Lightweight clothing: Dress in breathable, light layers.
5. Adjust room temperature: Keep the environment comfortably cool.
6. Over-the-counter medications: Use fever-reducing medications like acetaminophen or ibuprofen as directed.

Are there any home remedies to avoid when treating a fever? Yes, certain traditional remedies can actually be counterproductive or dangerous:

• Alcohol baths: These can lead to alcohol absorption through the skin.
• Ice baths: These can cause shivering, which raises body temperature.
• Overdressing: This can trap heat and increase body temperature.

When to Seek Medical Attention for a Fever

While many fevers can be managed at home, certain situations warrant professional medical care. Recognizing these scenarios is crucial for preventing potential complications.

Under what circumstances should you seek immediate medical attention for a fever? Consider seeking medical care if:

• An infant under 3 months has any fever
• A child’s fever persists for more than 3 days
• An adult’s fever lasts more than 3 days or exceeds 103°F (39.4°C)
• The fever is accompanied by severe symptoms like difficulty breathing, chest pain, or severe headache
• There are signs of dehydration
• The person has a compromised immune system
• The fever occurs after recent travel to a region with endemic diseases

How does the approach to fever differ for individuals with pre-existing conditions? People with chronic health conditions, weakened immune systems, or the elderly may need to seek medical attention sooner, even for lower-grade fevers. These individuals should consult with their healthcare provider to establish personalized guidelines for managing fevers.

Understanding Fever in Special Populations

Certain groups require special consideration when it comes to fever management due to their increased vulnerability or unique physiological characteristics.

How should fever be approached in infants and young children? Infants and young children are more susceptible to rapid temperature changes and the potential complications of high fevers. Parents should:

• Monitor temperature regularly
• Ensure proper hydration
• Consult a pediatrician for fevers in infants under 3 months
• Be aware of age-specific fever guidelines provided by their healthcare provider

What considerations are important for managing fever in the elderly? Older adults may not exhibit typical fever symptoms and might actually have a lower baseline temperature. Important considerations include:

• Monitoring for subtle changes in behavior or mental status
• Being aware that fever might manifest as confusion or weakness
• Ensuring proper hydration, as older adults are more prone to dehydration
• Consulting healthcare providers sooner, as infections can progress rapidly in this population

The Role of Fever in Disease Diagnosis

While fever is a common symptom across many illnesses, understanding its patterns and accompanying symptoms can provide valuable diagnostic information for healthcare professionals.

How can fever patterns aid in disease diagnosis? Different illnesses can produce distinctive fever patterns:

• Continuous fever: Temperature remains above normal throughout the day and does not fluctuate more than 1°C in 24 hours (e.g., lobar pneumonia)
• Intermittent fever: Temperature elevates and returns to normal each day (e.g., malaria)
• Remittent fever: Daily temperature fluctuations of more than 1°C, but never returns to normal (e.g., infective endocarditis)
• Relapsing fever: Fever-free periods alternating with fever spikes (e.g., rat-bite fever)

What additional symptoms can help differentiate between various fever-causing conditions? Accompanying symptoms can provide crucial diagnostic clues:

• Rash: May indicate viral infections or certain autoimmune conditions
• Cough and congestion: Often associated with respiratory infections
• Abdominal pain: Could suggest appendicitis or other gastrointestinal issues
• Joint pain: Might indicate rheumatic fever or other inflammatory conditions
• Headache and neck stiffness: Potential signs of meningitis

Fever and Immune Response

Understanding the relationship between fever and the immune system can provide insight into why fevers occur and their potential benefits.

How does fever contribute to the immune response? Fever plays several important roles in supporting the body’s defense mechanisms:

• Enhances immune cell function: Higher temperatures can increase the activity of white blood cells
• Inhibits pathogen growth: Some bacteria and viruses struggle to replicate at higher temperatures
• Boosts antibody production: Fever can stimulate the production of protective antibodies
• Increases metabolic rate: This can support faster healing and recovery

Can suppressing a fever be counterproductive? In some cases, yes. While fever-reducing medications can provide comfort, they may also potentially prolong illness duration by interfering with the body’s natural defense mechanisms. It’s important to balance symptom relief with allowing the body to mount an effective immune response.

Technological Advancements in Fever Monitoring

Modern technology has introduced new tools and methods for monitoring and managing fevers, both at home and in clinical settings.

What are some innovative tools for fever monitoring? Recent advancements include:

• Smart thermometers: Connected devices that can track temperature trends over time and sync with smartphone apps
• Wearable temperature sensors: Continuous monitoring devices that can alert caregivers to significant temperature changes
• Non-contact infrared thermometers: Allow for quick and hygienic temperature checks, particularly useful in public health screenings
• Thermal imaging cameras: Can detect elevated body temperatures in crowds, used in some public spaces for fever screening

How have these technologies impacted fever management? These innovations have:

• Improved early detection of fevers, especially in vulnerable populations
• Enhanced the ability to track fever patterns over time, aiding in diagnosis
• Facilitated remote monitoring, allowing healthcare providers to assess patients from a distance
• Supported public health efforts in managing infectious disease outbreaks

Global Perspectives on Fever Management

Approaches to fever management can vary across different cultures and healthcare systems, influenced by local traditions, available resources, and medical philosophies.

How do fever management practices differ around the world? Some notable variations include:

• Traditional Chinese Medicine: Often focuses on restoring balance rather than directly suppressing fever
• Ayurvedic practices in India: May incorporate herbal remedies and dietary adjustments to manage fever
• European approach: Generally more conservative in using antipyretic medications compared to the United States
• Low-resource settings: May rely more heavily on physical cooling methods due to limited access to medications

What can be learned from these diverse approaches? Studying global perspectives on fever management can:

• Provide insights into alternative treatment methods
• Highlight the importance of cultural sensitivity in healthcare
• Inform public health strategies for managing fevers in diverse populations
• Encourage a more holistic approach to fever management, considering both symptomatic relief and supporting the body’s natural processes

Future Directions in Fever Research and Management

As our understanding of fever and its role in health and disease continues to evolve, new areas of research and potential treatment approaches are emerging.

What are some promising areas of fever research? Current and future research directions include:

• Personalized fever management: Tailoring treatment based on individual genetic and immunological profiles
• Targeted thermal therapy: Using controlled hyperthermia to enhance immune responses against specific diseases
• Advanced fever prediction models: Developing algorithms to anticipate fever onset in at-risk populations
• Fever’s role in neurological health: Investigating the potential protective effects of fever in certain brain disorders

How might these research areas impact future fever management? Potential impacts include:

• More nuanced treatment guidelines that consider the benefits and risks of fever for individual patients
• Development of new therapies that harness the body’s temperature regulation mechanisms
• Improved early warning systems for detecting and managing febrile illnesses
• Better understanding of when to intervene in cases of fever and when to allow the natural process to unfold

As we continue to unravel the complexities of fever and its role in health and disease, our approach to managing this common but significant symptom will undoubtedly evolve. By staying informed about current research and best practices, individuals can make more informed decisions about when to seek medical care and how to support their body’s natural healing processes.

When Fevers Get Dangerous | iCare

Having a fever doesn’t necessarily mean that you need to visit a doctor. In fact, a fever can be a good sign because it shows that your body is fighting an illness or infection. A low-grade fever is an essential part of the immune response, and you will often feel better in a few days.

Why Does Fever Occur?

A fever isn’t an illness – it is a symptom of another health condition. Usually, the body develops a fever in response to an infection that is occurring. The illness or disease is detected, then the immune system kicks into gear to fight the virus or bacteria. This response stimulates the body’s defenses, sending out the white blood cells that are needed for protection. Fever can be caused by a variety of conditions, including:

• Flu
• Common cold
• Heatstroke
• Ear infections
• Pneumonia
• Sinus infection
• Internal infection
• Skin infection
• Bronchitis
• Urinary tract infections
• Blood clots
• Appendicitis
• Autoimmune diseases
• Rheumatoid arthritis
• Inflammatory bowel disease
• Cancer
• Hormone disorders
• Illegal drugs

Sometimes, fever is a temporary response to a specific cause. For example, young children often have a fever when teething or for a day or two after immunizations.

How Body Temperature Works

The average body temperature is 98.6 degrees F, but it is normal for the temperature to range between 97.7 degrees F and 99.5 degrees F throughout the day. For example, it is common for the body temperature to be higher in the evening compared to the morning. If the temperature goes above 99.5 degrees F, then it is considered a fever in both adults and children.

The body has built-in systems to maintain normal body temperature. Several organs affect temperature regulation, including the skin, brain, muscles, and blood vessels. If the body needs to cool down, then a few responses might occur:

• Sweat production increases to cool the skin
• Blood is moved closer to, or away from, the surface of the skin
• You feel the urge to move to a cooler environment
• Water in the body is retained or released through the sweat glands and urinary system

A fever is not the only factor that can increase body temperature. Heavy clothing, physical exertion, strong emotions, high heat and humidity, menstruation, and certain medications can increase body temperature. When you are taking a person’s temperature, check to ensure these other factors aren’t influencing the thermometer reading. For example, if a child has been running around, have them sit still for 20 minutes before using the thermometer to ensure you are getting an accurate reading.

Tips for Lowering a Fever

Just because a person has a mild fever, doesn’t mean that you need to be proactive in lowering the fever. Often, the best solution is to let the fever run its course by resting at home and staying hydrated. If you notice that the fever is increasing in severity, then these are a few things that can be done at home to see if the fever can be managed without medical treatment:

• Take a lukewarm bath (not cold water)
• Place a cool washcloth on the forehead
• Use over-the-counter acetaminophen, according to dosage directions on the package. Choose children’s brand medication for young members of your family.
• Adjust the thermostat in the house
• Remove blankets and heavy clothing
• Drink plenty of fluids, especially drinks with electrolytes to counteract the minerals lost through sweating

Even though ice baths and alcohol rubs are sometimes recommended as DIY fever treatments, these at-home methods should be avoided. Ice and alcohol rubs cause the body to shiver, which increases the internal temperature even more.

The main benefit of lowering a fever is to help the person be more comfortable, especially when they are trying to sleep at night. Additionally, body temperature regulation is essential to avoid potentially dangerous side-effects, such as seizures.

When is a Fever Dangerous?

A mild fever isn’t considered dangerous. If you or a family member has a low-grade fever with other common illness symptoms, then a few days of rest and healing at home might be just what the doctor ordered. But how do you know when it is time to seek medical attention? If the fever escalates, then it could potentially become dangerous.

These are a few signs that indicate you should seek medical attention immediately. Talk to the doctor if the fever is accompanied by:

• Bruising
• Rashes
• Difficulty breathing

Other signs that you need medical attention might include:

• You’ve recently received one or more vaccinations
• You visited another country recently
• You have a serious pre-existing condition
• A child seems confused or delirious
• A child won’t stop crying
• The person has a weakened immune system or other medical complications

Fevers in Children vs. Adults

One determining factor regarding whether medical care is needed is based on the severity of the fever and the age of the person. You should talk to a doctor when these criteria are met:

• 0 – 3 Months Old: The child has a rectal temperature at or above 100. 4 degrees F
• 3 – 12 Months Old: An oral temperature reading is at or above 102.2 degrees F
• 2 Years Old – Teenage Years: If the child’s fever lasts more than 24 – 48 hours
• Adults: If the fever is above 103 degrees F and lasts more than 48 hours. Any time an adult fever reaches 105 or more, talk to a doctor right away.

Medical Treatment for Fever

Since a fever is a symptom of an underlying condition, it is important to obtain an accurate diagnosis to determine the best treatment plan. For example, antibiotics might be recommended for a bacterial infection, such as an ear infection or strep throat.

If you need medical care right away, then visiting an Urgent Care might be the most effective solution. At our clinic, you don’t have to schedule an appointment or wait for an opening. Walk-ins are welcome! Your entire family has access to fast treatment for a variety of injuries and illnesses.

Visit us anytime to access high-quality services from our board-certified medical team. We provide both urgent care services and emergency treatments. Call iCare ER and Urgent Care if you have questions about available services, or if you would like to schedule an appointment.: (214) 407-8668.

What Is Considered a Fever? Symptoms & Treatment

It’s relatively common knowledge that the normal body temperature is 98.6° F (37° C), but your core body temperature actually varies by a degree or so throughout the day. For instance, your body temperature will be slightly lower in the morning and higher in the late afternoon into the evening. However, certain factors may cause your body temperature to dive below what’s considered normal or spike to pyrexia, more commonly known as a fever.

Unlike hypothermia, an emergency condition that develops when your body temperature reaches 95° F (35° C) or lower, a fever is fairly common and, in most cases, not very dangerous. Developing an elevated body temperature—whether it’s a high or low grade fever—is usually your body’s response to infection. Luckily, fevers typically last only a few days and there are several treatment options that can help you feel more comfortable.

What Is a Fever?

The normal human body temperature is 98.6° F (37° C), but other factors, including illness, certain medications, and specific medical conditions, can cause your temperature to rise. A fever is your body’s natural response to fighting an infection.

Any temperature between 98.6-100.4° F (37-38° C) is considered a low-grade fever, while any temperature above 103° F (39.4° C) is considered a high-grade fever. Unlike a significantly lower-than-normal body temperature, having a higher temperature isn’t necessarily dangerous.

One factor that differentiates what is considered a low or high body temperature is age. For adults and children, 95.1-96.9° F (35-36° C) is low and 100.4-103° F (38-39.4° C) is high, but neither case is necessarily an emergency. However, if a baby less than three months old experiences a temperature in either range, it may indicate a serious infection that requires immediate medical care.

This easy-to-read chart shows what various body temperatures mean and when to seek care. The measurements in this chart were made by mouth with the thermometer under the tongue.

See a doctor online.

Start my visit

Fever in Children

When adults develop a fever, they usually feel uncomfortable, but there’s typically no cause for concern, although an exception to this rule arises when an adult is undergoing chemotherapy treatment or has any condition which impairs the body’s ability to fight infections. When infants, toddlers, and children develop fever symptoms, they are more likely to need medical care.

If your toddler or child has a fever, but is still responsive, eating, drinking fluids, and playing, there’s no cause for concern. However, if your infant, toddler, or child experiences the following, you should either call your doctor or seek immediate care:

• More Irritable than usual
• Vomiting repeatedly
• A fever lasting more than three days
• Appears listless and unresponsive

Complications in children

Although fevers in children are quite common, some children between the ages of six months and five years may experience complications, such as febrile seizures or convulsions. Luckily, most children who experience fever-induced convulsions suffer no lasting effects and are not thought to be at higher risk of developing seizures or epilepsy later in life.

If your child has a seizure resulting from a fever, do the following:

• Lay your child on the floor on his or her side or stomach
• Clear the vicinity of any sharp objects
• Loosen any tight clothing
• Do not try to stop the seizure yourself
• Hold your child in place to prevent injury

Fever symptoms generally cause discomfort because your body is working to fight off an infection.

When you develop pyrexia, the most common symptoms you might experience include sweats, shivers, and headaches. Other common fever symptoms include:

• Chills
• Muscle aches
• Loss of appetite
• Irritability
• Dehydration
• Lethargy

What Causes a Fever?

Your body’s internal thermostat is controlled by a small area in your brain called the hypothalamus. When your hypothalamus sets your internal body temperature higher than usual, this results in a fever. Usually the hypothalamus will reset this internal thermostat to normal within a few days. Although infection (which can be caused by either bacteria or viruses) is more often than not the cause of your fever, other causes include:

• Heat exhaustion
• Inflammatory conditions, such as rheumatoid arthritis
• Malignant tumors
• Drugs for high blood pressure and/or seizures
• Specific immunizations, such as diphtheria, tetanus, and pneumococcal vaccines

Diagnosing a Fever

Unlike many other illnesses, diagnosing a fever is something you can do at home. You should only seek medical attention if your high fever lasts more than a few days or is accompanied by any concerning symptoms.

Taking a temperature

The most obvious indication of a fever is a body temperature that’s higher than normal. The best way to measure your temperature is to take it using a thermometer. There are several different types of thermometers, but the most popular is a digital one, which you can use orally, rectally or axillary (under your armpit). Regardless of which type of thermometer you use, always be sure that the batteries aren’t expired as that may skew the results.

Other types of thermometers include a tympanic thermometer, which measures the temperature inside of the ear by reading the infrared heat. Most pediatricians use this method to take babies’ temperature if they’re three months or older.

Here’s how to use a digital thermometer:

• Make sure your hands and the thermometer are clean.
• Do not eat or drink anything for at least five minutes before you take your temperature because the food/drink may skew the results.
• Place the thermometer tip under the tongue, into the anus (using a petroleum jelly), or into your armpit and wait about 40 seconds. Most thermometers will beep when they have an accurate reading.
• Remove the thermometer and clean it with soap and water or with alcohol. Afterwards, be sure to rinse it.

Treatments for Fever

If you have a low-grade fever (up to 100.4° F and 38° C ), the best treatment may be letting the fever run its course. Having a slightly elevated body temperature can help get rid of the illness-causing microbes that are responsible for your cold, flu, or other viral infection. In cases of a high fever, there are a number of actions you can take to help lower your body temperature.

How to break a fever

As previously mentioned, having a fever isn’t necessarily a bad thing. It’s a sign that your body is fighting off an infection. However, in some cases, breaking your fever, or reducing your body’s temperature, can be helpful in making you feel more comfortable. Some of the most common ways to break a fever include:

• Over-the-counter medications: There are a variety of over-the-counter medications, such as acetaminophen and ibuprofen, that can help break your fever. However, taking too much of these medications or using them regularly over a prolonged period of time can cause liver and kidney damage. Children should never take aspirin, as it can cause a potentially fatal disorder called Reye’s syndrome.
• Antibiotics or antivirals: Depending on what’s causing your fever, your doctor may prescribe an antibiotic for a bacterial infection and an antiviral for a viral infection. Taking either, as directed by your doctor, can help break your fever.
• Hydrate: Drink plenty of non-alcoholic or caffeinated fluids to counteract the dehydration associated with fever.
• Let your body rest: Getting ample rest and staying cool can also help lower your fever.

What to eat when you have a fever

While your body and immune system need nutrients to fight off infection, your illness may be accompanied by nausea or lack of appetite. In that case, do not force yourself to eat. In fact, you should only eat if you are able to keep down food and if you feel hungry. Although the best thing you can do for a fever is to drink plenty of fluids, eating chicken soup has proven helpful as well. Other helpful foods include:

• Greek yogurt: If you can tolerate dairy, greek yogurt is an excellent food to eat when you have a fever because it contains a lot of probiotics, which help your immune system.
• Coconut water: Coconut water is naturally rich in electrolytes and potassium.
• Fruits with vitamin C: Most fruits are at least 80% water, making them an excellent source of hydration. Fruits containing vitamin C, such as oranges, can also help improve your immune response.
• Protein-rich foods: Foods including beans, nuts, lean meat, and poultry are high in protein, which your immune system needs in order to produce antibodies and fight off an infection.

Fever Prevention

The most effective way to prevent a fever is to avoid contracting an infection. While that’s not always possible, you can take the following steps to minimize your exposure to germs and diseases:

• Wash your hands: Wash your hands often with an antibacterial soap for at least 20 seconds.
• Use hand sanitizer: If you’re traveling and water and soap aren’t immediately available to you, using a hand sanitizer with at least 60% alcohol will help kill any germs.
• Avoid touching your face: Even if you wash your hands or use hand sanitizer, you may still be at risk, so avoid touching your nose, eyes, and mouth to prevent contracting an infection.

When to See a Doctor

Just because you have a fever doesn’t mean you need to pay a visit to the doctor. However, if you have a fever of 103° F (39.4° C), you should call your doctor, especially if your fever is accompanied by any of the following:

• Severe headache
• Skin rash that worsens quickly
• Sensitivity to light
• Stiff neck and/or pain when you bend your head forward
• Mental confusion
• Consistent vomiting
• Difficult breathing and/or chest pain
• Abdominal pain and/or pain when urinating
• Convulsions and seizures
• Severe sore throat or difficulty swallowing
• You are undergoing chemotherapy or other treatments for cancer or have any underlying chronic condition which suppresses your immune system

See a doctor online.

Start my visit

How K Health Can Help

While most fevers you can handle at home, sometimes you may need to speak to a doctor to make sure nothing more serious is going on.

Did you know you can get affordable primary care with the K Health app?

Download K Health to check your symptoms, explore conditions and treatments, and if needed text with a clinician in minutes. K Health’s AI-powered app is based on 20 years of clinical data.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Fever | Didkovsky N.A., Tanasova A.N.

L fever – an increase in body temperature as a result of a non-specific protective and adaptive reaction of the body, characterized by a restructuring of thermoregulation processes and occurring in response to exposure to pathogenic stimuli. There are fever infectious and inflammatory nature (viruses, bacteria, intracellular parasites) and non-infectious genesis (autoimmune processes, allergic diseases, tumors, metabolic disorders, the use of certain drugs, etc.) [2]. The regulation of body temperature is carried out with a complex interaction of the nervous, endocrine and immune systems. The most common trigger in the development of hyperthermia are exogenous pyrogens (bacteria, viruses, toxins, etc.), which, when ingested, stimulate the production of endogenous pyrogens by blood cells [4].

Fig.1. The mechanism of development of fever under the influence of exogenous and endogenous pyrogens. ACTH – ACTH, CRF – corticotropin-releasing factor, PGE2 – prostaglandin E2 (CECIL Textbook of Medicine, 19 h edition).

Currently, 11 cytokines are known to have pyrogenic activity, the most important of which are interleukins – IL-1 and IL-6, as well as tumor necrosis factor – TNF-a [4]. Endogenous pyrogens are produced by stimulated monocytes and macrophages. The properties of pyrogens are also possessed by a-, b- and g-interferons. IL-1 and TNF-a are transported with the blood stream to target cells that carry specific receptors for these cytokines, and act on thermosensitive neurons in the preoptic region of the hypothalamus through increased prostaglandin (PG) synthesis E ₂ and PGF _2a from arachidonic acid.

Fig. 2. Metabolism of arachidonic acid (according to A.A. Yarilin) ​​[3]. International abbreviations for prostaglandins (PG), leukotrienes (LT) and thromboxanes (Tx) are used.

The exact mechanism of “switching” of the thermoregulation center under the action of PG has not yet been established. The direct effect of cytokines on the nervous tissue is not excluded. An increase in body temperature activates metabolic processes, the functions of the nervous, endocrine, and immune systems (an increase in the production of antibodies, interferon, an increase in chemotaxis, phagocytic and bactericidal activity of neutrophils), an increase in the antitoxic function of the liver, and an increase in renal blood flow. IL-1 and TNF-a are able to enhance the immune response by activating T-cells and stimulating the production of IL-2. Under the action of IL-1, B-cell proliferation is enhanced, which is accompanied by an increase in antibody formation. It is important to note that these processes proceed most intensively at a temperature of 39°C. Under the action of endogenous pyrogens, the synthesis of “acute phase” proteins (fibrinogen, C-reactive protein, complement fractions B, C 3-4, alpha-glycoprotein, serum amyloid A, proteinase inhibitors) is stimulated by the liver, which play an important role in specific and non-specific protection. Hyperthermia is accompanied by a decrease in serum levels of iron, zinc and copper, which inhibits the growth and reproduction of microorganisms.

In a typical course, fever goes through the following phases or periods – a prodromal period, a period of temperature rise, a period of relative stability, a period of decrease in body temperature, each of which is accompanied by certain vegetative reactions. What changes accompany the development of fever?

1) Tachycardia. With an increase in body temperature by 1 ° C, an increase in heart rate by 10–15 beats per minute occurs.

2) It is possible to develop extrasystole, which is due to both the direct toxic effect of bacteria and viruses, and the activation of the sympathetic-adrenal system under the influence of cytokines.

3) In the phase of temperature rise, an increase in blood pressure is possible, and in the phase of temperature decrease, blood pressure drops to a collaptoid state against the background of a decrease in TPS.

4) Upon reaching the maximum body temperature, the process of sweating increases significantly (up to 1 liter of sweat per day is possible), which can contribute to a decrease in BCC and lead to a deterioration in the condition of patients with pathologies of the cardiovascular system. Fluid losses are also aggravated by a compensatory increase in respiratory rate at the height of fever.

5) At the height of fever and even after normalization of temperature, transient appearance in the urine of protein, casts and an increase in creatinine levels is possible. These changes are associated with the direct damaging effect of fever.

6) Fever affects the activity of various parts of the gastrointestinal tract, which is manifested by impaired secretion of digestive juices, impaired motility and absorption processes. As a result, there may be a decrease in appetite, the development of a syndrome of impaired absorption and constipation (the latter has a particularly adverse effect on elderly patients). Loss of appetite during fever is associated both with functional disorders of the gastrointestinal tract and with the direct influence of cytokines. So, with prolonged exposure to high concentrations of TNF-a (which has a second name in Western literature – “cachectin”) and partially IL-1, depletion may develop due to the suppression of hunger / appetite (which is most typical for chronic infections and oncological processes).

7) Against the background of fever, metabolic processes in cells increase sharply (with an increase in body temperature by 0.6 ° C, the level of basal metabolism increases by approximately 10%), redox processes accelerate, and oxygen consumption increases. Hyperthermia can increase blood glucose levels, increasing protein catabolism (negative nitrogen balance). Loss of protein up to 300-400 grams per day is possible. A decrease in diuresis against the background of a reduced BCC can lead to the development of metabolic acidosis.

8) Changes in consciousness (from minor to the development of a delirious state) are associated with the release of b-endorphins under the influence of TNF-a and IL-1. The risk group includes young children, the elderly, patients with pathology of the cardiovascular system, as well as people who abuse alcohol.

9) Due to the immaturity of the central nervous system and the imperfection of the thermoregulation system in children under the age of 5 years, the development of febrile convulsions is possible.

10) An increase in body temperature can lead to the activation of latent herpesvirus infection (HSV-1). For reasons that are not completely clear, most often herpetic eruptions accompany diseases caused by a pyogenic bacterial infection (pneumococci, streptococci, meningococci), malaria, and rickettsiosis. Nasolabial herpes is a marker of reduced cellular immunity. It is important to note that subjective sensations during fever are of a different nature. Some patients are sensitive to even small fluctuations in body temperature, while others do not experience discomfort with a significant increase in temperature (for example, with pulmonary tuberculosis). However, in most cases, patients complain of weakness and malaise, headache, pain in the muscles and joints, chilling or excessive sweating, which “pushes” the doctor to prescribe antipyretics. When deciding on the need to prescribe non-steroidal anti-inflammatory drugs (NSAIDs), it is necessary to take into account both positive and potentially dangerous manifestations of fever. It must be remembered that fever, like any protective-adaptive reaction, with the depletion of compensatory mechanisms or with a hyperergic variant, can cause the development of pathological conditions. So, an excessive increase in temperature leads to inhibition of immune responses, impaired function of parenchymal organs, the development of febrile convulsions, functional and degenerative disorders in the cardiovascular and central nervous system. A critical decrease in body temperature can contribute to the development of collapse due to a sharp drop in total peripheral resistance and aggravate the condition of patients with pathology of the cardiovascular system.

So in what case is it necessary to use antipyretics?

An increase in body temperature within 3°C does not have a damaging effect on the human body, however, its increase by more than 6°C (i.e. more than 42.2°C) leads to irreversible changes in brain structures, which is a condition incompatible with life. When deciding on the need to prescribe NSAIDs, it is necessary to take into account the age of the patient, the severity of the underlying and concomitant diseases, as well as the subjective tolerance of fever.

Currently NSAIDs are widely used in the symptomatic treatment of fever in ARVI. However, little attention is paid to non-drug (physical) methods of lowering body temperature, which is especially important in pediatric practice. I would like to remind you that physical methods of lowering the temperature (such as wiping the body with a weak solution of vinegar, applying cold to the area of ​​large arteries, wet wrapping, a warm (not cold!) bath, an enema with water at room temperature) are recommended not only in domestic, but also in modern foreign literature, they can be quite effective and have no side effects. It is necessary to remember such rules for caring for patients with fever, such as an adequate drinking regimen, a sparing diet, mandatory ventilation of the room, and the prohibition to “wrap up” the patient, since the latter prevents heat transfer.

In febrile conditions on the background of infectious and inflammatory diseases, rectal suppositories Cefecon N are used as an antipyretic, anti-inflammatory and analgesic. Cefecon N suppositories are a unique combination of naproxen, caffeine and salicylamide, which ensures high antipyretic, analgesic activity. Cefecon H has a number of advantages over oral NSAIDs.

Before entering the systemic circulation, medicinal substances must pass through the stomach, small intestine, liver, where they are destroyed and adsorbed to a certain (sometimes significant) degree, which can lead to damage to this organ. Even if taken on an empty stomach, drugs enter the systemic circulation on average no earlier than 30 minutes later. When taking drugs orally in the form of powders and especially tablets, there is the greatest likelihood of their local irritating effect on the gastric mucosa.

With the rectal route of administration, the intake of substances adsorbed in the rectum is carried out simultaneously through the circulatory and lymphatic systems, which are especially developed in this area. In this case, an insignificant part of the adsorbed drugs enters the portal vein, which carries blood from the internal organs to the liver. Moreover, bioavailability from the rectal mucosa for a number of drugs is equivalent to that after intravenous administration. Thus, the introduction of NSAIDs in suppositories can reduce the risk of side effects from the gastrointestinal tract and ensure that the full dose of the drug is delivered, regardless of food intake and concomitant therapy (for example, antacids). In this regard, the use of NSAIDs in the form of rectal suppositories (Cefecon N) seems to be a very promising direction.

Despite the fact that, in the understanding of the patient, fever is often an undesirable manifestation of the disease, the doctor, when determining the strategy for treating the patient, must take into account the positive factors of the hyperthermic reaction. Moreover, the elimination of fever should not be the main goal of the therapy (which often occurs in the presence of SARS). It is well known that the course of an infectious disease without a temperature reaction may indicate that the patient has an immunodeficiency state and is an unfavorable prognostic factor.

1. Luchsheva Yu., Cold. How to deal with it. The effectiveness of symptomatic therapy for acute respiratory viral infections // Pharmaceutical Bulletin No. 37 (236), 2001.

2. NSAIDs: the role of rectal suppositories.//Russian Medical Journal, Vol. 10, No. 21(165), 2002, pp. 982–986.

3. Yarilin A.A., Fundamentals of immunology, M. “Medicine”, 1999, pp. 163–168.

4. Bruce Beutler, Steven M. Beutler, The Pathogenesis of Fever// CECIL Textbook of Medicine,19th edition, 1994, p.1568–1571.

5. Cranswick N, Coghlan D., Paracetamol efficacy and safety in children : the first 40 years// Am J Ther, 2000, 7(2): 135–41.

6. Glasow.J.F.T., Middleton B., Reye syndrome – insights on causation and prognosis// Arch Dis Child, 2001, 85, 351–353.

what to do, what temperature is considered high and why it is dangerous, causes and symptoms

Fever, fever – this is what we call an increase in body temperature. This is the most important defense mechanism of the human body and one of the main symptoms of infection. Most often, we encounter a fever with colds and flu. High temperatures cause some discomfort, but it helps to cope with the disease faster. We will tell you why adults have a fever, when it is necessary to bring down the temperature, and in what cases it is not worth it.

Why the temperature rises

¹

Body temperature can rise for various reasons: due to overheating, inflammation, hormonal imbalance. The processes of heat transfer in the human body are regulated by a small part of the brain – the hypothalamus. The temperature rises with any physical or chemical impact on it.

An increase in body temperature associated mainly with infections is called a fever. It develops when biologically active substances, cytokines, act on the hypothalamus. The immune system releases them into the blood in response to the inflammatory process. The production of cytokines is also enhanced by the waste products of microbes.

Fever is one of the main symptoms of an acute respiratory viral infection (ARVI). But it is also a protective reaction of the body, aimed at fighting the virus. When the temperature rises, the immune system synthesizes more leukocytes, which destroy or inactivate pathogenic microbes, and interferons, natural antiviral substances.

What temperature is considered high

^2.3

A temperature above 37˚C measured in the armpit is considered elevated. When measuring temperature in the oral cavity, a temperature of more than 37.2˚C is considered elevated, and in the rectum – more than 37.8˚C.

Types of fever:

● Subfebrile – 37.5–38˚C. Accompanies a chronic or easily flowing acute infection.

● Febrile – 38-39˚C. A frequent companion of most acute inflammatory processes – infectious and non-infectious.

● Pyretic (high) – 39-41˚C. This is one of the signs of a moderate flu. High fever is accompanied by symptoms that worsen well-being.

● Hyperpyretic (critically high) – more than 41˚C. It occurs in a severe form of influenza, causes life-threatening disorders of body functions.

What symptoms accompany fever

^{4, 5}

Subfebrile temperature is accompanied by weakness, feeling of weakness, headache, drowsiness, chills. At a temperature of 38˚C, the skin becomes hot, the cheeks turn red, the patient feels intense heat, dry mouth. Lips dry out and crack. With pyretic fever, nausea and vomiting may join. Hyperpyretic temperature is often accompanied by a disorder of consciousness, delirium.

Fever increases blood pressure and heart rate. An increase in temperature by one degree increases the pulse by 10-15 beats per minute.

What diseases occur with fever

⁶

The most common cause of fever in adults is acute respiratory viral infections (ARVI):

● Coronavirus, rhinovirus infection. This is SARS, affecting mainly the mucous membranes of the nasal cavity and pharynx. Symptoms: runny nose, redness and sore throat, sneezing, coughing. The temperature is subfebrile (37–38˚С) or febrile (38–39C).

● Influenza. Influenza viruses can immediately affect the lower respiratory tract and cause a deep chest cough. Infection is most often accompanied by severe intoxication, which is manifested by headache, aching throughout the body, and severe weakness. The temperature can reach pyretic (39-41˚C) and hyperpyretic (over 41˚C).

● Respiratory syncytial virus infection. It often affects the trachea and bronchi, in a quarter of the patients it leads to pneumonia. Symptoms are similar to the flu, with the difference that intoxication is less pronounced, signs of inflammation of the lower respiratory tract come to the fore – a deep cough with pain behind the sternum.

● Parainfluenza. The virus infects the nasal cavity, pharynx, larynx. The infection is accompanied by a runny nose, bouts of painful coughing, hoarseness, and sometimes a short-term loss of voice.

● Adenovirus infection. Runs with severe runny nose, sneezing, conjunctivitis. The eyes turn red, watery, there is pain and burning in the area of ​​​​the eyeballs and eyelids. Unlike other acute respiratory viral infections, adenovirus infection is often infected in spring and summer.

Other causes of fever:

● any infectious disease of a viral, bacterial, parasitic nature;

● non-infectious inflammations: acute pancreatitis, aspiration pneumonitis;

● allergic and autoimmune diseases: reaction to vaccination, rheumatoid arthritis, systemic lupus erythematosus;

● diseases of the thyroid gland, adrenal glands;

● oncological diseases: malignant tumors of internal organs, leukemia, lymphogranulomatosis;

● neurological pathologies: traumatic brain injury, cerebral hemorrhage;

● thermal (solar) stroke;

● psychogenic: prolonged emotional stress, neuroses, hysteria.

When temperature is dangerous

Fever poses a threat to health with a strong rise in temperature, when the thermometer shows 40˚C or more. This condition leads to dehydration, disruption of vital organs, and significantly increases the risk of thrombosis.

For healthy adults, an increase in temperature during SARS by 3˚C from the norm (36.6˚C) is not dangerous. However, for some people, even a febrile temperature can be harmful. At risk:

● Elderly people. After 65 years, it is more difficult for the body to adapt to an increase in temperature due to the age-related decrease in the ability to thermoregulate, the acquisition of chronic diseases.

● People with chronic diseases of internal organs: kidneys, cardiovascular, nervous system. Fever increases the load on these organs and can lead to an exacerbation of the disease.

What to do when the temperature is high

⁷

Fever helps to defeat the infection faster. With ARVI without fever, the infection takes longer, is accompanied by a pronounced deterioration in well-being, and is more often complicated. Therefore, it is worth suffering malaise for 2-3 days and not bringing down the temperature, provided that the body temperature does not exceed 38.5˚C. To make it easier to transfer the condition, avoid any physical activity, drink plenty of fluids, do not wrap yourself in blankets and excessively warm clothes that impair heat transfer.

But there are times when it is better to bring down the temperature:

● The thermometer reads over 39˚C.

● The rise in temperature is accompanied by a strong deterioration in the condition: loss of strength, poor sleep, nausea, vomiting.

● The patient is at risk.

Fever above 40˚C in adults requires emergency medical attention.

Non-drug methods. Wiping with a damp cloth or a weak vinegar solution will help to reduce the temperature. It is recommended to drink more warm drinks, such as tea with raspberry jam. Raspberries contain natural salicylates – substances that reduce fever. Drink should be moderately warm. Excessively hot or cold drinks and foods should be avoided.

Antipyretics. If non-drug remedies do not help, take antipyretics. The safest drugs are paracetamol-based, which can be taken even by small children and pregnant women. Paracetamol is included in most combined anti-cold complexes, which additionally relieve nasal congestion and symptoms of intoxication in acute respiratory viral infections.

Antivirals. Lowering the temperature is not an end in itself in the treatment of SARS. Antiviral therapy should fight the causative agent of the infection. To do this, develop specific antiviral drugs that prevent the reproduction of the virus and infection of healthy cells. In the treatment of colds and flu, enisamium iodide has proven itself well. Its use reduces the acute clinical manifestations of viral intoxication. ⁸

Enisamia iodide at a dosage of 500 mg is part of the drug Nobasit ^® Forte ⁸ . Nobasit ^® Forte begins to act within 2 hours after taking the tablet ^8. In addition to the direct antiviral effect, enisamia iodide has a pronounced anti-inflammatory activity ^{9, 10} . The combined action leads to a decrease in the severity of fever and other symptoms of intoxication (headache and muscle pain) by 3 times, starting from the second day of treatment ¹¹ . Also Nobasit ^® Forte helps to reduce the duration of the disease. ⁸

Briefly about the main

● Elevated is defined as a temperature above 37˚C measured in the armpit. If it is caused by an infection, this temperature is called a fever.

● The most common cause of fever in adults is SARS. Other causes – infections, non-infectious inflammation, heat stroke, stress, malignant tumors – are much less common.

● Fever brings recovery closer, but often it greatly affects well-being: it is accompanied by weakness, headache, body aches. In the elderly and people with common chronic diseases, fever often causes dangerous complications.

● Cool down in healthy adults should be above 38.5˚C and in at-risk people above 38˚C. If the temperature rises above 40˚C, it is worth calling an ambulance.

● First, try to bring down the temperature with home remedies – cool body wraps, tea with raspberry jam. If that doesn’t help, take an antipyretic medicine.

● Antipyretics will ease the fever but will not speed up recovery. To defeat the infection as soon as possible, take antiviral drugs, for example, Nobasit ^®
Forte.

¹ Tatochenko V.K., Uchaikin V.F. Fever // Pediatric pharmacology – 2006 – https://cyberleninka.ru/article/n/lihoradka

² Fugol D.S. An increase in body temperature in children and approaches to its correction // BC – No. 24, 2013 – https://elibrary.ru/item.asp?id=20603056

³ Vasilenko V.V. Measurement of body temperature // RMJ. – No. 29, 2008, S. 1948. https://www.rmj.ru/articles/istoriya_meditsiny/Izmerenie_temperatury_tela/

⁴ Dvovetsky L.I. Fever: to treat or not to treat // BC – No. 14, 2003 – https://www.rmj.ru/articles/obshchie-stati/Lihoradka_lechity_ili_ne_lechity/

⁵ Cheshik S.G., Vartanyan R.V. Respiratory syncytial viral infection: clinic, diagnosis, treatment // Children’s infections – No. 1, 2004 – https://cyberleninka.ru/article/n/respiratorno-sintsitialnaya-virusnaya-infektsiya-klinika-diagnosti…

⁶ Kalyuzhnaya L.I., Zemlyanoy D.A. Heat transfer disorders and fever // Pediatrician – T.6, No. 1, 2015 – https://cyberleninka.ru/article/n/narusheniya-teploobmena-i-lihoradka

⁷ Didkovsky N.A., Tanasova A.N. Fever. breast cancer. 2003; 4:189.

⁸ Instructions for medical use of the drug Nobasit® Forte LP-006416.