Fever

The normal temperature of the human body is approximately 37 degrees Celsius (°C) or 98.6 degrees Fahrenheit (°F). It can vary by about 0.5 °C throughout the day.

However, in the case of a fever, the elevation in core body temperature is usually more than 0.5 °C.

Fever is defined as having a measured temperature of 100.4 °F (38 °C) or higher. Depending upon the cause, the person may experience other signs and symptoms which include:

• Sweating
• Shivering
• Hot, red, dry skin
• Headache
• Dehydration
• Muscle aches
• Loss of appetite
• Tiredness
• Nausea
• Vomiting
• Piloerection (goosebumps)
• Dizziness
• Increase in heart rate
• Convulsions

Note: The normal baseline body temperature can vary from person to person. Therefore, it is important to consider this variability before indicating fever.

Fever is the body’s defense system that fights infection. However, a severe fever may indicate a critical condition requiring immediate medical intervention.

Before understanding the exact cause of fever, it is essential to know about the pyrogens:

Pyrogens are substances that provoke fever. There are two types of pyrogens:

• Exogenous pyrogens: These substances originate from outside the body and can induce endogenous pyrogens. Examples include bacteria, viruses, toxins, and drugs.
• Endogenous pyrogens: These are certain substances produced by the body that can induce fever.

Fever occurs through the following steps:

1. Exogenous pyrogens trigger the release of endogenous pyrogens.
2. These endogenous pyrogens are transmitted to the thermoregulatory center in the hypothalamus (a part of the brain that controls many body functions).
3. It induces the synthesis of other chemicals, such as prostaglandins.
4. These prostaglandins raise the body’s set-point temperature, leading to fever.

Did you know?

Hyperthermia, or overheating, can also cause a sudden and uncontrolled increase in body temperature (above 41°C). This is usually caused by excessive heat from the surroundings.

However, it is different from fever. In a fever, the hypothalamus increases the body’s set-point temperature. Meanwhile, in hyperthermia, the body’s core temperature rises above the set point due to a thermoregulation failure.

Heat exhaustion and heat stroke are forms of hyperthermia.

The various factors that can initiate the above response are:

1. Infection
   Infections are the major contributor to fever. The list below mentions a few common causes of infections that can trigger fever:
   • Respiratory infections: Cold, Croup, Pneumonia
   • Ear infections: Otitis media
   • Gastroenteritis
   • Urinary tract infection
   • Measles
   • Mumps
   • Malaria
   • Dengue
   • Chikungunya
   • Typhoid
   • Leptospirosis
   • Tuberculosis
   • Brain infections: Meningitis, Encephalitis, and brain abscess
   • Herpes infection
   • Hepatitis A
   • HIV infection
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2. Hypersensitivity
   Hypersensitivity refers to an exaggerated or inappropriate immune system response to exposure to an allergen. It increases the occurrence of fever. Common allergens include:
   • Pets
   • Dust mites
   • German cockroaches
   • Grass
   • Fungi
   • Plants
   • Bee and wasp venoms
   • Eggs
   • Milk
   • Latex
   • Antibiotics
   • Shellfish
   • Food allergies
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3. Blood transfusion
   Blood transfusion often triggers an immune response due to mismatch or incompatibility of the transfused product and the recipient. This immune response can cause fever immediately or a few days after the transfusion.
4. Medications
   Some medications can also cause fever. Drug-induced fever most commonly occurs after 7 to 10 days of drug administration. It remains as long as the medication is taken and goes away shortly after discontinuing it. The agents most commonly associated with causing fever include:
   • Penicillins
   • Cephalosporins
   • Antituberculars
   • Quinidine
   • Procainamide
   • Methyldopa
   • Phenytoin
5. Nutritional deficiencies
   Malnourished individuals have weakened immunity, making them more prone to developing fever due to frequent infections. Here are some tips to prevent nutritional deficiencies in children. Tap to Know
6. Cancer
   Cancer often causes fever due to the release of pyrogenic chemicals from tumor cells. The most common cancers that cause fever are:
   • Lymph node cancer
   • Kidney cancer
   • Liver cancer
   • Blood cancer
   • Ovarian cancer
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7. Autoimmune disorder
   An autoimmune disorder refers to a condition in which the body’s immune system attacks its own cells. Fever usually develops in such conditions. Autoimmune conditions commonly associated with fever are:
   • Systemic erythematous lupus (inflammation and tissue damage to organs such as joints, skin, brain, lungs, kidneys, and blood vessels)
   • Rheumatoid arthritis
8. Ischemic conditions
   Ischemia is a condition in which the blood supply is restricted to an area of the body. Fever-causing ischemic conditions include:
   • Stroke
   • Heart attack
   • Pulmonary embolism

Did you know? Women usually suffer from hot flashes and night sweats during perimenopause (the period around menopause). These are due to hormonal changes and should not be confused with fever.

Diagnosis may involve detailed medical history and lab tests to identify the cause of fever.

1. Medical history
   A thorough medical history helps identify the exact cause of the fever. The information regarding the following points is captured through patient interaction:
   • Onset and duration of fever
   • Degree of temperature
   • Mode of measuring temperature by the patient
   • Medications
   • Exposure to any toxins
   • Recent travel
   • Recent vaccination
2. Physical examination
   It includes looking for signs such as shock, weak peripheral pulses, increased heart rate, respiratory distress, spots on the skin, discoloration of the skin, and decreased mental status.
3. Temperature measurement
   
   • Oral temperature: Used for cooperative patients older than 4-5 years of age. A temperature taken using a mouth thermometer of 100 °F (37.8 °C) or higher is considered a fever.
   • Axillary temperature: Determines peripheral temperature, not core body temperature. A temperature reading of >37.2°C (>99°F) is considered high.
   • Rectal temperature: Measures temperature in children 3 years or younger. A temperature of 38°C (100.4°F) or higher is considered a fever. A special rectal thermometer measures rectal temperature.
   • Ear (tympanic temperature): Measured using special tympanic thermometers or digital ear thermometers. A temperature higher than 37.9°C (100.2°F) is considered fever.
   • Forehead temperature: Measured using electronic forehead thermometers that read the heat waves from the temporal artery. Forehead temperature is usually 0.3 °C (0.5 °F) to 0.6 °C (1 °F) lower than oral temperature.
   The accuracy of all modes of temperature measurement is as follows:
   Rectal > Forehead > Oral and Ear > Axillary
4. Blood tests
   Depending on the symptoms and medical history, certain blood tests can aid in identifying the cause of fever:
   • Complete blood count
   • Erythrocyte sedimentation rate (ESR)
   • C-reactive protein (CRP)
   • Procalcitonin
   • Serum lactate dehydrogenase (LDH)
   • Rheumatoid factor (RF) test
   • Antinuclear antibody (ANA) test
   • Creatine phosphokinase test (CPK)
   • Serum protein electrophoresis
5. Urine routine and microscopy
   Urine tests can help to rule out any urinary infections.
6. Stool culture and sensitivity
   A stool culture is indicated if there is a suspicion of bacterial enteritis, usually done in the presence of specific symptoms, such as blood in the stool or certain exposures.
7. Lumbar puncture
   Lumbar puncture refers to inserting a hollow needle into the space surrounding the spinal column to collect cerebrospinal fluid (CSF). CSF is a clear, colorless, watery fluid that flows in and around the brain and spinal cord. A lumbar puncture is necessary when sepsis, meningitis, or encephalitis is suspected.
8. Imaging tests
   Based on the above results, various imaging tests are performed, including chest radiographs and magnetic resonance imaging. Note: Individuals can be prescribed other specific tests according to their history and symptoms.

Certain preventive measures can reduce the risk of developing a fever. Some of these general measures include:

1. Ensure timely vaccination: Vaccination can cause short-term fever but reduces recurring fevers caused by infections throughout life. Children and adults should receive all vaccine doses according to age and schedule.
2. Maintain hand hygiene: Many viral infections can be prevented by washing hands with soap and water for at least 10 seconds, especially:
   • After going to the toilet
   • Before preparing or handling food
   • Before eating food
   • After handling the vomit of an infected patient
   • After changing the diapers of a child
   There is also evidence that alcohol-based hand sanitizers and hand washing can reduce the chances of viral infections in offices and daycares. A reduction in school absenteeism is also observed.
3. Maintain proper sanitation: Infectious diseases can spread through contaminated surfaces. Practicing good hygiene is the best way to prevent infection. The following measures can be taken to ensure cleanliness:
   • Keep nails short and avoid wearing false fingernails, nail extenders, nail polish, and jewelry, as these restrict adequate hand cleaning.
   • Clean surfaces or objects that have been exposed to vomit or feces.
   • Wear disposable gloves and masks while handling feces or vomit of infected individuals.
   • Dry hands using disposable paper towels. Avoid using cloth towels, as bacteria can survive on them.
   • Keep kitchen tops, toys, toilet seats, and nappy change tables clean to avoid the growth of bacteria and viruses.
4. Assess your cooking techniques: Contaminated food and beverages are significant sources of infection, and some dietary modifications can help prevent it:
   • Cook food thoroughly.
   • Avoid consuming uncooked and unpasteurized milk.
   • Drink only bottled water while traveling.
   • Avoid food buffets, uncooked foods, peeled fruits and vegetables, and ice in drinks.
   • Studies suggest that daily administration of probiotics, especially in children, reduces the occurrence of infection.
5. Boost your immunity: A strong immune system helps in combating infections. Maintain a healthy lifestyle with a balanced diet, regular exercise, adequate sleep, and stress management to support immunity.

The goal of the treatment of fever is to:

• Bring the temperature into the normal range
• Treat the underlying cause
• Prevent any complications

The following medications are commonly prescribed for the management of fever:

1. Paracetamol (Acetaminophen)
   It is an analgesic (pain killer) and antipyretic (fever reducer) medication used to relieve mild-to-moderate pain and fever. It is sold over the counter (OTC) at pharmacies, supermarkets, and other retail establishments. It is available as tablets, capsules, and syrups (for children). Make sure to adhere to the prescribed dosage.
2. Nonsteroidal anti-inflammatory drugs (NSAIDs)
   This drug category decreases inflammation, pain, and fever by blocking the production of prostaglandins (chemicals that raise the body's temperature). Examples include:
   • Ibuprofen
   • Aspirin
   • Naproxen
   • Diclofenac
   They are commonly prescribed in combination with Paracetamol.
3. Antibiotics
   Antibiotics are prescribed in case of suspicion of an infection. The type of antibiotics prescribed depends on the symptoms and diagnosis. Examples include:
   • Cefadroxil
   • Amoxicillin
   • Cefixime
   • Doxycycline
   • Tetracycline
   • Azithromycin
   • Cefazolin
   • Cephalexin
   • Ciprofloxacin
   • Clarithromycin

Here are some Do’s and Don’ts when suffering from fever:

DO’S

• Check the temperature with a thermometer. It is advisable to check the temperature using a thermometer rather than guessing by placing your hand on the forehead or neck.
• Cold sponging or tepid water sponging. Dip a cloth or sponge in cold or lukewarm water, squeeze it gently to remove excess water, and place it on the forehead.
• Stay hydrated. Drink plenty of fluids if you have a poor appetite due to the infection.
• Remove excess clothing. Wear light, loose cotton clothes, as excess clothing can increase body temperature.

DON’TS

• Layer with multiple blankets. Bundling yourself with blankets does not reduce fever and may raise body temperature, except in cases of cold or shivering.
• Starve. Although appetite may be lost during fever, starvation should be avoided as it can leave a person weak and unable to fight infections.
• Self-medicate. Avoid self-medicating and consult a doctor if you have a high fever (above 102 degrees Fahrenheit) or feel excessively weak.
• Perform strenuous activities. Avoid excessive physical exertion as it can worsen the condition and lead to soreness.

First aid: Tips to follow for high-grade fever

• Monitor the temperature with a thermometer.
• Make the person rest in a comfortable, cool environment under a fan or air conditioner.
• Cover them with light clothing if the person experiences chills.
• Administer 500 mg paracetamol every 6 hours around the clock.
• Give the person a sponge bath with lukewarm water.
• Encourage them to drink plenty of water or cool drinks.
• Visit a doctor if the fever does not subside in 24 hours.
• Call for an ambulance or rush the person to the hospital if the temperature exceeds 106 °F.

What should you do if your child has a fever?

• Administer plenty of fluids to prevent dehydration.
• Administer paracetamol according to your child's weight as directed by your physician.
• DO NOT use aspirin.
• Dress your child in light clothing to help cool the body.
• Avoid force-feeding; provide adequate fluids (2-3 liters) to maintain hydration and urine output.
• Use a cool, wet cloth for fomentation on the forehead.
• Give a bath with lukewarm water to lower body temperature.
• Avoid sending your child to school or daycare until their temperature is normal for at least 24 hours.
• Ensure that your child gets enough rest and sleep.

Note: It is crucial to seek immediate medical care if your child is 3 months or younger and has a temperature higher than 100.4 °F (38°C). This is a serious condition that requires professional attention.

Home remedies

Some traditional home remedies can aid in recovery from fever. Here are a few:

• Giloy (Guduchi or ‘Amrita): This herb boosts immunity and helps reduce fever. It can be consumed as juice by blending the chopped branches with a cup of water, straining, and drinking. Giloy supplements are also available.
• Holy basil (Tulsi): Known as the 'Queen of herbs', Tulsi has excellent antibacterial and fever-reducing properties. Boil 10-12 Tulsi leaves in a glass of water for 10 minutes, strain, and drink every 2-3 hours for maximum effect. Tulsi drops are also available.
• Turmeric (Haldi): This spice boosts immunity and reduces fever, possessing antibacterial and antioxidant properties. Mix a teaspoon of turmeric in a glass of warm milk and consume before bedtime.
• Ginger (Adrak): With its antibacterial properties, ginger is effective against fever and cough. Add a pinch of grated ginger to a cup of boiling water and consume 1-2 times a day.
• Garlic (Lehsun): Garlic has antibacterial properties beneficial for managing fever. Add 2-3 crushed garlic pods to a quarter cup of warm water, strain, and consume.

A sustained, severely elevated fever can lead to lethal effects within multiple organ systems:

• Neurologic damage
• Low blood pressure
• Gastrointestinal inflammation
• Edema
• Acute kidney injury
• Liver damage
• Spontaneous bleeding
• Increased clotting times
• Thrombocytopenia

Remember! A pregnant woman with a fever, rash, and joint pain might indicate an infection that could harm the baby. Immediately contact a doctor for timely supervision.

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