What is a high-grade fever in adults? When should you seek medical attention for a fever? Get the answers to these questions and more on fever and temperature in adults.

Understanding Fever in Adults

Fever is the body’s natural response to fight off an infection. When your immune system detects an infection, it triggers an increase in white blood cells, which in turn causes your brain to raise your body temperature in an effort to kill off the invading germs. This rise in temperature is what we know as a fever.

While fever is generally a good sign that the body is working to combat an illness, there are times when a fever in adults can be cause for concern. Let’s take a closer look at what constitutes a high-grade fever, when you should seek medical attention, and other important considerations around fever in adults.

What is a High-Grade Fever in Adults?

A high-grade fever in adults is considered to be 103 degrees Fahrenheit (39.4 degrees Celsius) or higher. This elevated temperature signals that the body is working hard to fight off an infection or illness.

It’s important to note that not all fevers are created equal. In fact, a fever can range anywhere from about 97 to 99 degrees Fahrenheit, which is considered the “normal” body temperature range. So a temperature of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher is considered a fever, but not necessarily a high-grade one.

When Should You Seek Medical Attention for a Fever?

So when should you be concerned about a fever and seek medical care? Here are some key signs that it’s time to see a doctor:

• Your temperature is 103 degrees Fahrenheit (39.4 degrees Celsius) or higher.
• Your fever has not gone down after taking over-the-counter fever reducers like acetaminophen or ibuprofen.
• Your fever lasts for several days or keeps coming back.
• You live in an area with active COVID-19 cases and have a fever, even if you’re fully vaccinated.
• You have a serious underlying health condition like diabetes, heart disease, cancer, lupus, or sickle cell anemia.
• You are pregnant.
• You have recently traveled internationally.
• You get infections frequently.
• You are undergoing chemotherapy treatment.
• You have recently been bitten by a tick.

In these cases, it’s best to seek medical attention to determine the underlying cause of the fever and get appropriate treatment. Leaving a high-grade or persistent fever untreated could lead to serious complications.

Is 98.6 F Still Considered “Normal” Body Temperature?

You’ve likely heard that the average “normal” body temperature is 98.6 degrees Fahrenheit (37 degrees Celsius). However, research suggests that this number is more of a myth than a reality.

Doctors now believe that the normal body temperature range is actually between 97 and 99 degrees Fahrenheit (36.1 to 37.2 degrees Celsius). The reason for this shift is likely due to a few factors, including lower metabolic rates, decreased rates of infection, and more accurate digital thermometers.

So while 98.6 degrees Fahrenheit is still considered within the normal range, it’s not necessarily the definitive “normal” temperature that it was once thought to be.

The Bottom Line on Fever in Adults

Fever is a natural and often beneficial response by the body to fight off infection or illness. In adults, a high-grade fever of 103 degrees Fahrenheit (39.4 degrees Celsius) or higher is a sign that the body is working overtime to combat an underlying issue.

If you experience a high fever that doesn’t respond to fever reducers, persists for several days, or is accompanied by other concerning symptoms, it’s best to seek medical attention. Your doctor can help determine the cause of the fever and provide appropriate treatment to help you recover.

Key Takeaways on Fever in Adults

• A high-grade fever in adults is 103 degrees Fahrenheit (39.4 degrees Celsius) or higher.
• Seek medical attention if your fever is high, doesn’t respond to medication, lasts for several days, or is accompanied by other concerning symptoms.
• While 98.6 degrees Fahrenheit was once considered the “normal” body temperature, research suggests the normal range is actually between 97 and 99 degrees Fahrenheit.
• Fever is the body’s natural response to fight infection, but in some cases it can be a sign of a more serious underlying condition.

Fever & Temperature In Adults: When To Worry

Karen Justiniano, DO, MS, Stamford Health Medical Group

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A friend of mine whose father is 70 years old told me her story. It went something like this:

“My father never gets fevers. Out of nowhere the other day, he developed a 103 temperature with no other symptoms. He is also fully vaccinated against COVID-19. My mother brought him to the emergency room. Did she do the right thing, or would he likely have been fine if he stayed home and let the fever run its course?”

As a physician who cares for a variety of people with a variety of conditions, I have to say of course she did the right thing! When in doubt or when concerned, seeking medical attention is the smart thing to do.

But the longer answer is a little more complicated than that. It all starts with breaking down the purpose of a fever, and when you should truly worry. Please note—fevers in infants or young children are sometimes a different story—what you are about to read relates to adults only.

What is a fever and why do we get them, and sometimes with no other symptoms?

Fever is an elevated body temperature which means your temperature is 100.4 degree F or higher. A fever is the body’s way of fighting an infection by naturally raising your body’s temperature to “kill the germ.” The medical community likes to say that fever is a “good thing,” in most cases.

And yes, it’s completely possible for adults to develop a fever with no other symptoms, and for doctors to never truly find the cause. Viral Infections can commonly cause fevers, and such infections include COVID-19, cold or the flu, airway infection like bronchitis, or the classic stomach bug.

That’s why you often hear the word “viral” as an explanation because these types of infections often go away on their own after a few days.

What is considered a high fever in adults?

A high-grade fever in adults is 103 degrees F or higher.

Is it possible that a fever could be a sign of a “breakthrough case” of COVID-19 even if the person is fully vaccinated?

Yes, but not highly likely. Breakthrough cases of COVID-19 in fully vaccinated people have been reported, but symptoms tend to be milder than in non-vaccinated people, including fever.

First, make sure you are taking your temperature the right way. Taking your temperature by mouth is the most accurate method, and wait at least 30 minutes after you eat or drink anything hot or cold. Get medical attention for your fever if:

• Your temperature is high and has not gone down after taking Tylenol or Advil
• Your temperature lasts several days or keeps coming back
• You live in an area where people have COVID-19
• You have serious health conditions like diabetes, heart disease, cancer, lupus, or sickle cell anemia. (Non-infections like these can cause fever as well.)

You should also seek medial attention if you have a fever and you:

• Are pregnant
• Recently returned from travel overseas
• Get infections often
• Are on chemotherapy, in which case you should seek medical attention immediately if the fever lasts for more than one hour.
• Have recently been bitten by a tick

Is 98.6 still considered “normal” body temperature?

Yes and no. You’ve probably always heard that the average body temperature is 98.6, but the truth is there’s a much wider range—from about 97 to 99 degrees F.

So why is 98.6 suddenly a myth after all these centuries? Research suggests body temperatures are falling overall. Doctors have a few ideas about why this is, including lower metabolic rates, lower rates of infection and more advanced thermometers.

A couple of helpful reminders:

1. As the saying goes, “Don’t fear the fever.” A fever is your body’s first line of defense in fighting off an infection.
2. If you are not fully vaccinated against COVID-19, and have developed a high-grade fever, please call your doctor right away.

Characteristics, Types, and When It’s Serious

A fever is a common side effect of illness like the flu. It happens when there is a temporary rise in body temperature. A fever is usually a sign that your immune system is busy fighting an infection or other illness.

In babies and toddlers even a slight fever may be a sign of a serious illness. In adults a fever is not usually serious or life-threatening.

However, sometimes a fever in adults can be a warning signal that something is not right. A high or persistent fever might be a sign of a serious health condition.

A fever is normally a short-term rise in temperature that helps your body get rid of illness. A fever begins when your immune system makes more white blood cells to fight an infection. The increase in white blood cells triggers your brain to heat your body up.

This causes a fever. In response, your body tries to cool itself off by tightening up on blood flow to your skin and contracting muscles. This makes you shiver and may cause muscle aches.

Your normal body temperature ranges from 97°F to 99°F (36.1°C to 37.2°C). You may have a fever if your temperature rises above this.

Adults typically have a fever if their body temperature increases to 100.4°F (38°C). This is called a low grade fever. A high grade fever happens when your body temperature is 103°F (39.4°C) or above.

Most fevers usually go away by themselves after 1 to 3 days. A persistent or recurrent fever may last or keep coming back for up to 14 days.

A fever that lasts longer than normal may be serious even if it is only a slight fever. This is because a recurrent fever might be a sign of a more serious infection or health condition.

Common fever symptoms in adults include:

• sweating
• chills (shivering)
• headaches
• muscle pain
• loss of appetite
• fatigue
• weakness

Call your doctor immediately if you have a high grade fever — when your temperature is 103°F (39.4°C) or higher. Get medical help if you have any kind of fever for more than three days. Let your doctor know if your symptoms get worse or if you have any new symptoms.

Serious symptoms

A fever may be a sign of serious illness if you have:

• a severe headache
• dizziness
• sensitivity to bright light
• stiff neck or neck pain
• skin rash
• difficulty breathing
• frequent vomiting
• dehydration
• stomach pain
• muscle cramps
• confusion
• seizures

Other signs that a fever may be serious are:

• pain when urinating
• not urinating enough
• passing dark urine
• passing urine that smells bad

If you have serious fever symptoms, let your doctor know if you have recently traveled to a different country or attended an event that had lot of people. This may help your doctor find out the cause.

Common causes of a fever in adults are:

• viral infection (like the flu or a cold)
• bacterial infection
• fungal infection
• food poisoning
• heat exhaustion
• serious sunburn
• inflammation (from conditions like rheumatoid arthritis)
• a tumor
• blood clots

Some adults may have a higher risk of getting a fever. If you have a chronic health condition or have been treated for a severe illness, you may be more likely to get a serious fever.

Let your doctor know about any fever symptoms if you have:

• asthma
• rheumatoid arthritis
• diabetes
• Crohn’s disease
• heart disease
• sickle cell disease
• liver disease
• kidney disease
• chronic lung disease
• cystic fibrosis
• cerebral palsy
• stroke
• multiple sclerosis
• muscular dystrophy
• HIV or AIDS

Some medications and treatments can also lead to a serious fever, these include:

• antibiotics
• blood pressure drugs
• seizure medications
• DTaP vaccine
• pneumococcal vaccine
• steroids
• chemotherapy
• radiation treatment
• methotrexate
• azathioprine
• cyclophosphamide
• post-transplant medications

A fever is not normally harmful on its own. Most fevers go away within a few hours to days as your body defeats an infection.

Help yourself feel better with these at-home flu remedies:

• stay hydrated by drinking plenty of fluids, such as:
  • water
  • juice
  • soup
  • broth
• eat light foods that are easy on the stomach
• rest
• use a cool compress, like a damp towel
• take a warm sponge bath
• dress in light, comfortable clothing
• turn down the temperature in your room

Over-the-counter medications can help ease your fever and symptoms, like headaches and muscle pain:

• ibuprofen (Advil, Motrin)
• acetaminophen (Tylenol)
• naproxen (Aleve, Naprosyn)

You may need treatment from your doctor for more serious causes of a fever. The treatment depends on the cause. Your doctor may prescribe medications to treat serious infections:

• antibiotics
• antivirals
• antifungals

A fever may be a sign of serious illness. A high fever can also cause serious side effects.

Emergency Symptoms

Get emergency medical attention by going to the ER or calling an ambulance if you have any of these symptoms:

• seizure or convulsions
• fainting or loss of consciousness
• confusion
• hallucinations
• severe headache pain
• stiff or painful neck
• difficulty breathing
• hives or a rash
• swelling in any part of the body

A fever in adults is usually not harmful on its own. It is a sign that your body is dealing with an infection or other illness. In some cases a high or long-lasting fever can be a sign of a serious illness. You may need urgent medical treatment.

Do not ignore a fever. Get plenty of rest and fluids to help your body heal. See your doctor if you have a fever that lasts longer than 3 days or if you have other severe symptoms.

If you have a chronic condition or have been treated for a serious illness, let your doctor know if you have any kind of fever.

Determination of antibodies to hantaviruses, causative agents of hemorrhagic fever with renal syndrome in the blood – Blood tests by ELISA

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Determination of antibodies to hantaviruses, causative agents of hemorrhagic fever with renal syndrome in blood

Deadline

up to 2 days

Hemorrhagic fever with renal syndrome (HFRS) is an acute viral natural focal human disease of a zoonotic nature, characterized by systemic damage to small vessels, hemorrhagic diathesis, hemodynamic disorders and the development of acute renal failure.

Rodents are the reservoir of viruses. The isolation of the virus into the external environment occurs with urine, feces and saliva of rodents.

Ways of transmission of infection to humans – airborne, alimentary and contact. The incubation period lasts from 14 to 21 days.

HFRS disease is proved by serological confirmation of the presence of a virus in the human body – the appearance of specific immunoglobulins of classes M and G or an increase in the amount of IgG. Immunoglobulins of class M (IgM) to hantaviruses can be detected in the blood serum of patients as early as 1–7 days after the onset of symptoms of the disease. The concentration of IgM reaches its maximum values ​​by 8–25 days, and by the end of the third month from the onset of the disease, they cease to be detected. Determination of this serological marker allows early laboratory diagnosis of HFRS.

Immunoglobulins of class G (IgG) to hantaviruses begin to be produced in the human body 2-9 days after the onset of symptoms of the disease, and after 18-22 days their concentration in the blood reaches its maximum values.

Blood for serological studies by ELISA is taken from the patient on an empty stomach or not earlier than 6 hours after a meal, provided that he did not eat eggs and fatty foods.

Otherwise, the serum may be cloudy (chylous), unsuitable for testing.

You can drink water.

Blood is usually obtained from the cubital vein in an amount of 5-7 ml, by specially trained personnel.

Delivery of the sample to the laboratory within 2 hours.

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Tests in the morning, results in the afternoon

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Temperature for oncology, what is the temperature for cancer in an adult in the early stages?

Is there a temperature in cancer? Yes, an increase in body temperature in oncological diseases is a common phenomenon, and its causes are different. The temperature in cancer does not belong to the typical signs of a malignant process, only in rare cases, cancer cells are able to independently initiate a temperature reaction by releasing, as expected, active substances. One cannot but agree that an oncological patient has more reasons for an increase in body temperature, both internal and iatrogenic – arising as a result of therapeutic measures.

Causes of fever

There are several reasons for fever in a cancer patient, but most often the temperature in oncology is a consequence of some processes:

• Vital activity of tumor cells producing biological products. This leads to systemic hyperthermia, which occurs in some types of lung adenocarcinoma, when a paraneoplastic syndrome develops with debilitating fever and joint pain. After removal of the tumor, all pathological manifestations disappear.
• Existence of a cancer conglomerate in tissues. Due to a decrease in local immunity and impaired blood supply, inflammatory changes develop, for example, with lung carcinoma or lung metastases.
• Reactions of the body to the absorption of toxic substances from a decaying cancer node.
• Aggressive therapeutic measures. As a rule, these are complications of immune suppression after a course of chemotherapy. From this list, we can conclude that fever is most common in metastases, when malignant cells have spread throughout the body and the disease requires more aggressive treatment.

In all cases, it is necessary to quickly understand, without an accurate understanding of the pathogenetic mechanism of the temperature reaction, it is impossible to prescribe adequate treatment. Sometimes the identification of causal relationships requires more effort than the diagnosis of a malignant tumor.

Temperature indicators in cancer

Does the temperature always rise in oncology? A fever in an oncological patient, as well as a decrease in the thermometer below 35.5 ° C, is an abnormal condition, the body temperature in cancer should be normal, and this should be strived for when choosing a treatment.

Daily fluctuations in heat transfer are natural in healthy people, the difference between morning and evening thermometer readings can reach up to one degree. Active movements and eating, nervousness and a nightmare also change degrees, but this is imperceptible to a person.

Failure of adaptive mechanisms in a cancer patient slows down the normalization of temperature fluctuations, stretching in time. Even a slight change in heat transfer affects the work of all organs: the nervous system is depleted, the cardiovascular system reacts, immune mechanisms and reparative processes are inhibited.

The normal range is two degrees between 35.5° and 37.4°, the rest is pathological.

Subfebrile temperature in cancer

Subfebrile body temperature in oncology is limited to 37.5°C to 38°C. This is a pre-febrile condition, but it is believed that short-term subfebrile condition does not require therapeutic intervention.

A prolonged increase – more than 5-7 days without a tendency to normalization will not be resolved without the complicity of a doctor, its cause may be inflammation and even sepsis, requiring the appointment of antibacterial drugs.

When a zone of reduced blood supply appears in the center of the cancerous conglomerate with the formation of necrosis – the disintegration of the tumor tissue can begin with local hyperthermia – local heating of the soft tissues above the focus, and with an increase in the volume of decay products absorbed into the general bloodstream, lead to persistent low-grade fever.

High fever in cancer

High temperature or febrile fever is detected when the thermometer is above 38°C. On the one hand, this indicates a protective reaction of the body, but the temperature after chemotherapy is usually an unfavorable consequence of a significant decrease in neutrophilic granulocytes, a subtype of leukocytes.

Fever with a decrease in immune cells in eight out of ten cases is due to a septic condition in the absence of “classic” signs of blood poisoning and requires emergency treatment.

Quite often, prolonged fever slightly above 38°C manifests multiple liver lesions with cancer metastases with the development of liver failure.

A high temperature can manifest a malignant brain tumor located near the center of thermoregulation, or perforation into the abdominal cavity of a carcinoma of the colon or stomach.

Low temperature in cancer

Is there a temperature below normal in oncology? Yes, it happens, and it is also dangerous. A decrease in the thermometer below 36 ° C with an increase or decrease in the number of leukocytes, along with persistent tachycardia or shortness of breath, can also be a manifestation of systemic inflammation syndrome – sepsis. Moreover, low body temperature in oncology does not necessarily have to be accompanied by a pronounced decrease or increase in the number of leukocytes, less than 4 thousand or more than 12 thousand is enough, but functionally incapable of an adequate fight against infectious agents.

Temperature during chemotherapy

Chemotherapy requires a normal body temperature – a marker of the normal state of the body at a given time. Any deviations of thermoregulation from the norm can be a manifestation of sluggish inflammation or intoxication. Chemotherapy for a decaying cancer conglomerate can aggravate the pathological process and cause internal bleeding.

An increase in temperature during chemotherapy and the development of a febrile state a week after the course indicates hematological complications that are life-threatening in case of insufficient immunological protection.

Is it necessary to bring down the fever in oncology?

To begin with, let’s figure out what temperature is acceptable for oncology. Do not needlessly ask the question: “What temperature is not dangerous for cancer?” – in a malignant disease, any violations of heat transfer are unfavorable. In part, degrees above the norm are not even important, it is enough that there is a temperature in cancer when it should not be.

If the temperature rises due to oncology: what to do? You can reduce the temperature reaction by taking NSAIDs if it is hard for the patient’s body, but it is more correct to immediately consult a doctor. Primary differential diagnosis is carried out at the patient’s bed, the main thing is to exclude blood poisoning against the background of a malignant process.

The development of cancer without an increase in temperature is quite possible, but at different periods of the disease, its increase may be a complication of the treatment or progression of the tumor lesion. It is necessary to quickly figure out if the patient has a temperature with cancer, and most importantly, accurately diagnose and offer the best solution to the problem. Euroonco has all the conditions for adequate medical care for any patient and at any time of the day.

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References

1. Pathophysiology 4th ed. ed. Novitsky V.V., Goldberg E.D., Urazova O.I.; GOETAR-Media; 2009; v. 1.
2. Ptushkin VV/ Treatment and prevention of infections in patients with neutropenia// Mater. III Ross. oncol. conf.; 2003.
3. Sakaeva D.