Fever in an adult: causes, symptoms, what to do, treatment

Fever is an increased body temperature. Temperature is considered elevated when it is over 37.8 ° C measured with a thermometer in the mouth, or over 38.2 ° C measured with a rectal thermometer. Many people use the term "fever", often meaning that they feel too high a temperature, sometimes too low, "sometimes hot, sometimes cold," or simply "sweaty." In this case, the temperature was not measured.

Although 37 ° C is considered normal, body temperature changes throughout the day. The temperature is coldest early in the morning, and the highest is in the late afternoon, sometimes reaching 37.7 ° C. By the same principle, heat is never kept at a constant temperature. Sometimes the temperature peaks every day and then returns to normal. This process is called intermittent fever. Or the temperature may change but not return to normal. This process is called relapsing fever. Doctors no longer adhere to the opinion that the nature of the increase and decrease in temperature is extremely important in the diagnosis of some disorders.

Heat effects

Most of the symptoms are due to the condition causing the fever, not the fever itself.

While many are concerned that fever can be harmful, the characteristic temporary rises in body temperature up to 38-40 ° C, provoked by most short-term (acute) diseases, are well tolerated by healthy people. However, mild fever can be relatively dangerous for people with heart or lung disease, as it increases heart rate and breathing rate. Fever can also worsen the mental status of people with dementia.

Extremely high temperatures (generally over 41 ° C) can be harmful to health. Such a high body temperature can provoke dysfunction and, ultimately, failure of many organs. Such large rises in temperature can sometimes occur due to acute infections (such as sepsis, malaria or meningitis), but most often due to heatstroke or use of certain drugs and drugs. Some drugs (such as cocaine, amphetamines, and phencyclidine), anesthetics, and antipsychotics can cause severe fever.

Causes

The substances that cause fever are called pyrogens. Pyrogens can occur both inside and outside the body. Microorganisms and the substances they produce (such as toxins) are examples of pyrogens that arise outside the body. Pyrogens in the body are usually produced by monocytes and macrophages (two types of white blood cells). Outside pyrogens generate heat by stimulating the body to produce its own pyrogens or by directly affecting the temperature-controlling region of the brain.

Infection is not the only cause of fever. Fever can also be caused by inflammation, drug reaction, allergic reaction, autoimmune diseases (when the body produces abnormal antibodies that infect its own tissues) and an unnoticed cancer (especially leukemia and lymphoma).

Many diseases cause fever. They are broadly classified as

• infectious (most common);
• neoplastic (cancer);
• inflammatory.

An infectious cause is extremely likely in adults who have a fever for no more than 4 days. A non-infectious cause most likely results in a fever that lasts or is long or recurs intermittently. Fever is associated with many types of cancer and inflammatory diseases. Inflammatory diseases include diseases of the joints, connective tissues and blood vessels, such as rheumatoid arthritis, systemic lupus erythematosus (lupus) and giant cell arteritis.

Sometimes the rise in temperature is caused by medications taken.

Also, a short-term (acute) increase in temperature in cancer patients or in patients with an inflammatory disorder is most often triggered by an infection. In healthy people, a high fever is most likely not the primary symptom of a chronic illness.

Common Causes

In essence, all infectious diseases cause fever. But, in general, the most likely reasons are:

• upper and lower respiratory tract infections;
• gastrointestinal infections;
• urinary tract infections;
• skin infections;

Most acute respiratory and gastrointestinal infections are of viral origin.

Risk factors

Certain conditions (risk factors) make some people more prone to fever. These risk factors include the following:

• the general state of human health;
• the age of the patient;
• some professions;
• the use of certain medical procedures and drugs;
• contact with infections (for example, while traveling or contact with infected people or insects).

Diagnostics

Typically, a doctor can determine the presence of an infection based on a brief medical history, examination and a few simple tests, such as a chest x-ray and analysis urine. However, sometimes the cause of the increased temperature is not immediately established.

During the initial examination of a patient with a sharp rise in temperature, doctors pay attention to two main symptoms:

1. Headache or cough: These symptoms help narrow down the range of possible causes.
2. Determining the severity or chronic condition of the disease: Many acute viral infections are difficult to diagnose specifically (that is, it is difficult to identify the virus that is causing the infection). Testing only for people with serious and chronic medical conditions will help to avoid many expensive, unnecessary and, more often than not, unsuccessful tests.

Warning signs

In people with hot fever, certain signs and characteristics are cause for concern. They include:

• changes in mental function, such as disorientation;
• headache, neck pain when tilting the head, or both;
• flat, small, purple-red dots on the skin (petechiae) that indicate subcutaneous bleeding
• low blood pressure;
• rapid breathing or increased heart rate;
• dyspnea (dyspnea);
• temperature above 40 ° C or below 35 ° C;
• a recent trip to regions where a serious infectious disease such as malaria (as an endemic disease) is prevalent;
• recent use of drugs that suppress the immune system (immunosuppressants).

When to see a doctor

If you have warning signs, you should see a doctor immediately. As a rule, in such cases, immediate tests and, most often, hospitalization are required.

People without warning signs should see a doctor if the fever persists for more than 24 to 48 hours. Depending on the person's age, other symptoms and known pathologies, the doctor may ask the patient to come for an examination or recommend home treatment. As a rule, you should see a doctor if the fever persists for more than 3-4 days, regardless of other symptoms.

What the doctor does

Doctors first ask the patient about their symptoms and medical history. They then do a physical examination. Medical history and physical findings often suggest a cause for the fever and tests that may need to be performed.

The doctor asks the patient questions about current and previous symptoms and disorders, medications being taken, exposure to infections, and recent travel. The nature of the temperature rarely helps the doctor make a diagnosis, except for a rise in temperature after a day or two, which is typical for malaria. Doctors consider malaria as a probable cause only if the person has traveled to areas where malaria is common.

Recent travel can tell your doctor the cause of your fever, as some infections only occur in certain countries.

Recent contact with certain materials or animals is also important. For example, people who work in a meat processing plant are more likely to develop brucellosis (a bacterial infection that spreads through contact with pets).

Pain is an important sign of a possible source of fever, which is why the doctor asks questions about pain in the ears, head, neck, teeth, throat, chest, abdomen, side, rectum, muscles and joints.

Other symptoms that can help determine the cause of the fever include nasal congestion and / or discharge, coughing,diarrhea and urinary symptoms (frequency, urge, and pain during urination). Information about enlarged lymph nodes or rash (including its appearance, location, and time of onset in relation to other symptoms) can help the doctor pinpoint the cause. People with recurring fever, night sweats, and weight loss may have chronic infections such as tuberculosis or endocarditis (an infection of the inner lining of the heart and usually the heart valves)

The doctor may also ask about the following:

• Was there any contact with a sick person.
• Known conditions and diseases that predispose to infection, such as HIV infection, diabetes, cancer, organ transplant, sickle cell anemia or diseases of the heart valves, in particular with an artificial valve.
• Known disorders that predispose to fever without infection, such as lupus, gout, sarcoidosis of the lungs, overactive thyroid gland (hyperthyroidism) or cancer.
• Using drugs that predispose to infection, such as chemotherapy drugs for cancer, corticosteroids and other drugs that suppress the immune system.
• Injecting drug use.

The physical examination begins with a temperature measurement. Most accurately, the temperature is measured by the rectal method. The doctor then examines the patient from head to toe to determine the source of the infection or signs of illness.

Analyzes

The need for tests depends on what the doctor learns during the physical examination.

In healthy people with acute fever and only vague general symptoms (eg, general state of malaise and weakness), most likely, a viral disease that will pass on its own without treatment. Therefore, they do not need to be tested. The exception is people who have had contact with an animal or insect that is carriers or transmitters of specific diseases (vectors), for example, people with tick bite and those who have recently traveled to countries where specific diseases are common (eg malaria).

If an otherwise healthy person shows signs of a specific disease, it may be necessary to carry out some tests. Doctors select tests based on these signs. For example, if a patient suffers from headache and neck pain when tilting the head, a lumbar puncture (lumbar puncture) is done to establish meningitis. If the patient has a cough or pulmonary congestion, a chest x-ray is taken to check for pneumonia.

Patients at increased risk of infection, patients suffering from a serious illness, and the elderly very often tests are required, even if the examination results do not indicate any specific disorder. In such cases, the doctor performs the following tests:

• complete blood count (including the number and ratio of different types of leukocytes);
• chest x-ray;
• general urine analysis.

An increase in white blood cell count usually indicates an infection. The ratio of different types of white blood cells (leukocyte formula) provides further clues. For example, an increase in the number of neutrophils indicates a relatively new bacterial infection. An increase in the number of eosinophils indicates the presence of parasites such as tapeworms or roundworms. Also, blood and other body fluids are sent to the laboratory for growing microorganisms in culture. Other blood tests can be used to detect antibodies for specific microorganisms.

Fever of unknown origin

Fever of unknown origin (LDL) can be diagnosed if the patient has both minimum 38.3 ° C for several weeks, and if extensive surveys have not established a specific reason. In such cases, the cause may be a rare chronic infection or non-infectious disease, such as connective tissue disease and cancer.

Doctors usually do blood tests, including a CBC, bacterial culture blood tests, tests to assess liver function (liver function tests) and studies for impaired connective fabrics. Other tests, such as a chest x-ray, urinalysis, and urine culture.

Ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI), particularly of areas that are uncomfortable, can help the doctor figure out the cause. Radionuclide scanning after intravenous administration of radiolabeled leukocytes can be used to identify areas of infection or inflammation.

If these tests are negative, the doctor may take a tissue sample from the liver, bone marrow, or other area of ​​the suspected infection in order to conduct a biopsy. The sample is then examined under a microscope, cultured, and analyzed.

Treatment

Since fever helps the body fight infection and is not dangerous in itself (if it does not exceed 41.1 ° C), there are different opinions about whether it is worth bringing down the increased temperature. However, in most cases, patients feel better when their temperature drops. In addition, patients with cardiac or pulmonary diseases, as well as dementiaare at increased risk of dangerous complications. Therefore, in such cases, the increased temperature must be brought down.

Medicines used to lower body temperature are called antipyretics.

The most effective and widely used antipyretics are acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, and naproxen.

Typically, one of the following is prescribed:

• 650 mg acetaminophen every 6 hours (not to exceed the 3,000 mg daily dose);
• 200–400 mg ibuprofen every 6 hours.

Because most OTC cold and flu medications contain acetaminophen, be careful not to take acetaminophen with any of these medications at the same time.

Other means to lower the temperature (for example, cooling by spraying with warm water or using a cooling blanket) are only necessary if the temperature exceeds 41 ° C. Sponge soaked in alcohol should be avoided as alcohol absorbed through the skin can have harmful effects.

The main things older people need to know are: fever;

Temperatures rise differently in older people, as the body reacts differently from younger people. For example, an infection is unlikely to cause fever in frail elderly people. Even if the temperature rises due to infection, it may be lower than the standard definition fever, and therefore the severity of the fever may not correspond to the severity diseases. Other symptoms, such as pain, may also be less noticeable. Often, changes in mental function or deterioration in daily functions are the only other sign of pneumonia or urinary tract infection.

However, older people with fever are more prone to serious bacterial infections than younger people. As with young people, the most common cause is an infection of the respiratory tract or urinary tract. Skin and soft tissue infections are also a common cause in older people.

Diagnosis is the same as for younger people; in addition, doctors usually recommend urine tests (including culture) and chest x-rays for the elderly. Bacteriological tests are performed on blood samples to rule out a blood infection (sepsis).

Elderly people with blood disease or abnormalities in the main indicators of the state of the body from the norm (for example, low blood pressure, rapid heart rate and respiratory rate) are hospitalized.