Fever: diagnosis and treatment update

2021-06-18 04:55 PM

When someone has a fever, the signs and symptoms are related to what are called disease characteristics. In a fever patient, look for signs of serious illness first, then try to identify the diagnosis.

Fever is a temporary increase in body temperature in response to illness.

The child has a fever when the temperature is equal to or higher than one of the following:

38°C is measured at the base (rectum).

37.5°C measured intraoral (oral).

37.2°C measured under the arm (armpit).

Adults can have a fever when the temperature is above 37.2 - 37.5°C, depending on the time of day.

A symptom is something that a patient feels and reports, while a sign is something others, including a doctor, can detect. For example, a headache could be a symptom while a rash could be a sign.

When someone has a fever, the signs and symptoms are related to what are known as disease features, and can include:

A fever is considered if the temperature in the mouth is above 37.7 degrees Celsius (99.9 degrees Fahrenheit). The temperature may also be taken rectally (anus), under the arm, or inside the ear.

Feel cold.



Loss of water.


Musculoskeletal pain.


Concentration problems.



In a febrile patient, look for signs of serious illness first, then try to confirm the diagnosis.

Fever in children

An infant or young child with a fever of unknown origin.

Fever is defined as a rectal temperature exceeding 38°C. Guidelines for the initial evaluation of these patients are directed toward identifying or excluding serious bacterial infections, most commonly urinary tract infections, meningitis, and pneumonia.

Urinary tract infections and sepsis are major causes of fever in infants and young children.


Obtaining an accurate history from parents or caregivers is important when assessing for fever without markers; The history obtained must include the following information:

History of fever: What was the child's temperature before onset and how long did it last? Treat a fever recorded at home by a parent or trusted caregiver like a current fever. Accept parent reports of maximum temperatures.

Present fever: If the physician believes the infant has been over swaddled, and if repeated temperatures are taken 15-30 minutes after a transient is normal, the infant should be considered fever-free. Always remember that a normal or low temperature does not rule out a serious, even life-threatening, infectious disease.

The current level of activity or consciousness.

The level of activity before the onset of fever (ie, activity, consciousness).

Current diet.

Diet before the onset of fever.

Symptoms: Fever sometimes makes children appear quite tired.

Vomiting or diarrhoea.

Including diseases.


History of immunizations (especially recent immunizations).

Urine output: Ask about the number of wet diapers.

Clinical examination

During the physical examination, special attention should be paid to assessing hydration status and identifying the source of infection. The clinical examination of each febrile child should include the following:

Record vital signs.

Temperature: Rectal temperature is standard. Temperatures obtained by ear, armpit, or oral methods may not accurately reflect the patient's body temperature.



Blood pressure.

Measure the oxygen concentration in the pulse.

Pulse oximetry may be a more sensitive predictor of lung infection than the respiratory rate in patients of all ages, but particularly in infants and young children.

Pulse oximetry is mandatory for any child with pulmonary abnormalities, respiratory symptoms, or an abnormal respiratory rate, although keep in mind that respiratory rate increases with fever.

Record the exact weight on the chart.

All drug treatments and procedures are based on the weight in kilograms.

In emergency situations, estimation methods can be used (eg, Brose low tape, age-based weight).

While testing, focus on identifying any of the following:

Intoxication occurs, suggesting possible signs of coma, poor perfusion, hypoventilation or hyperventilation, or cyanosis (ie, shock).

An infection is the obvious cause of the fever.

Small foci (eg, otitis media, pharyngitis, sinusitis, skin, or soft tissue infection).

Identifiable viral infection (eg, bronchiolitis, pneumonia, gingivitis, viral gastroenteritis, chickenpox, hand, foot and mouth disease).

Purpura is often associated with sepsis

Purpura more commonly associated with Neisseria meningitis than with the presence of petechiae.

For all patients 2 to 36 months of age, management decisions are based on the degree of toxicity and identification of a serious bacterial infection.


For children with unexplained fever who present with fatigue, conduct a full evaluation to identify sources of infection. Follow-up assessment with empiric antibiotic therapy and admission to hospital for follow-up and further treatment pending culture results.

Patients 2 to 36 months of age may not require hospitalization if the following criteria are met:

The patient was healthy before fever.

The patient is fully immunized.

The patient had no significant risk factors.

The patient appears to be uninfected and healthy.

The patient's parents (or caregivers) appear to be trustworthy and have the right to use transportation if the child's symptoms are going to get worse.

Treatment recommendations for children with fever without focus are based on the child's appearance, age, and temperature.

For children without signs of toxicity, treatment recommendations are as follows:

Schedule a follow-up visit within 24-48 hours and instruct parents to return the child sooner if the condition worsens.

Hospitalization is indicated for children whose condition has worsened or whose evaluation indicates a serious infection.

The need to consult a specialist depends on the expertise of the physician who initially assessed the patient and the ultimate source of the fever. Usually, paediatricians easily manage febrile infants, both as an inpatient and outpatient monitoring facility.

Symptomatic treatment

Undress the patient and reduce fever.

Oral Paracetamol

Children: 60 mg/kg/day in 3 or 4 divided doses;

Adults: 3 to 4 g/day, divided into 3 or 4 times either;

Oral aspirin (to be avoided in children under 16 years of age)

Adults: 1 to 3 g/day, divided into 3 or 4 times.

Oral Ibuprofen

Children under 3 months do not use.

Children over 3 months: 30 mg/kg/day in 3 divided doses.

Children over 15 years old about 35 kg. Tablets 200 mg 1 to 2 tablets x 3 times.

Adults: 1200 to 1800 mg/day in 3 to 4 divided doses.


Paracetamol is the drug of choice for pregnant and lactating women.

Acetylsalicylic acid should not be used during the first 5 months of pregnancy, is contraindicated from the beginning of the 6th month, and should be avoided in lactating women.

Ibuprofen is not recommended during the first 5 months of pregnancy and is contraindicated at the beginning of the 6th month. It can be used in lactating women as a short-term treatment.