Fever without focus

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Questions and Answers

What defines fever in children based on oral and rectal temperature measurements?

Fever is defined as a rectal temperature of more than 38°C (100.4°F) or an oral temperature that exceeds 37.7°C (99.9°F).

What are exogenous pyrogens, and can you provide two examples?

Exogenous pyrogens are substances from outside the body that induce fever; examples include bacteria and viruses.

Name two endogenous pyrogens and their role in fever.

Two major endogenous pyrogens are IL-1 and TNF; they help raise the hypothalamic set point for temperature.

What is the primary physiological mechanism that turns fever into a body response?

Fever is primarily driven by the activation of macrophages that release cytokines, leading to the production of prostaglandin E2. Signup and view all the answers

List two forms of antipyretic medications used for managing fever in children.

Paracetamol and Ibuprofen are commonly used antipyretics for managing fever in children. Signup and view all the answers

What key factor differentiates patients at high risk for developing sepsis?

Patients with persistent high fever and significant lethargy or respiratory distress are at high risk for developing sepsis. Signup and view all the answers

Why is it important to monitor temperature in children with fever?

Monitoring temperature helps assess the severity of the illness and the effectiveness of treatment. Signup and view all the answers

When should empiric therapy with antibiotics be initiated in children with fever?

Empiric therapy with antibiotics should be initiated when there is a high suspicion of a bacterial infection, especially in high-risk patients. Signup and view all the answers

What is the highest temperature range generally accepted as fever?

Fever is generally accepted as a body temperature range between 37.5°C and 41°C (99.5°F and 105.8°F). Signup and view all the answers

What are the key components of a full sepsis workup for a high-risk pediatric patient?

The key components include Complete Blood Count (CBE), CRP, electrolytes, venous blood gas, blood culture, urine culture, chest X-ray, and possibly a lumbar puncture. Signup and view all the answers

Under what conditions should a pediatric patient with suspected sepsis be admitted to the PICU?

A pediatric patient should be admitted to the PICU if they exhibit lethargy, poor conscious state, respiratory distress, or signs of poor perfusion. Signup and view all the answers

What is the recommended initial treatment for a toxic pediatric patient with suspected sepsis?

The recommended initial treatment includes starting intravenous fluids and administering empiric antibiotics such as ceftriaxone plus flucloxacillin or vancomycin if MRSA is considered. Signup and view all the answers

Why should aspirin be avoided in children under 18 years, and what alternative treatments can be used?

Aspirin should be avoided due to the risk of Reye's syndrome; alternative treatments include ibuprofen and mefenamic acid for fever management. Signup and view all the answers

What is the significance of a temperature over 39°C in a child aged 3 months to 3 years with no clear infection source?

A temperature over 39°C in this age group indicates a potentially serious infection, necessitating further investigation, especially if accompanied by a well-appearing child. Signup and view all the answers

What measures can be taken to help manage a febrile child aside from antipyretics?

Management includes ensuring adequate fluid intake, using tepid water sponge baths, and adjusting the room temperature to keep the child comfortable. Signup and view all the answers

What effect do antipyretics have on PGE2 production?

Antipyretics block PGE2 production. Signup and view all the answers

What is the hypothalamus's temperature threshold during a fever?

The hypothalamus will not allow the temperature to rise above 41.5°C. Signup and view all the answers

How does a fever benefit white blood cells (WBCs)?

WBCs work best and kill most bacteria at temperatures between 38-40°C. Signup and view all the answers

What are two potential disadvantages of a fever?

Fever can cause hypercatabolism leading to nitrogen wastage and electrolyte imbalances due to sweating. Signup and view all the answers

What severe complications may arise from extremely high fevers?

High fevers can lead to febrile convulsions and brain damage. Signup and view all the answers

When might a newborn present with hypothermia instead of fever?

Newborns usually present with hypothermia, indicating potential infection or issues with body temperature regulation. Signup and view all the answers

What does fever without localizing signs indicate in pediatric patients?

Fever without localizing signs may indicate an underlying infection and accounts for about 70% of pediatric consultations. Signup and view all the answers

What is the impact of fever on the replication of Coxsackie and polio viruses?

Fever inhibits the replication of Coxsackie and polio viruses. Signup and view all the answers

What is the typical duration of fever associated with acute onset in pediatric patients?

Fever of acute onset typically lasts less than 1 week. Signup and view all the answers

How can fever contribute to circulatory issues?

Fever can lead to circulatory overload and arrhythmia. Signup and view all the answers

What is the significance of age in evaluating serious bacterial infection in children?

Younger children have a higher risk of serious bacterial infections such as septicemia and meningitis. Signup and view all the answers

Identify two groups of children who are at higher risk for serious bacterial infections.

Infants under 3 months with a temperature ≥38°C, and children aged 6-36 months who are not fully immunized. Signup and view all the answers

What are the first two steps in evaluating a patient with fever without localizing signs?

Conduct a detailed head-to-toe history and physical examination, followed by re-evaluation and specific laboratory tests. Signup and view all the answers

List two risk factors for neonatal sepsis.

Premature rupture of membranes for more than 12 hours and maternal fever greater than 38°C. Signup and view all the answers

What pathogens are commonly implicated during the neonatal period?

Group B Streptococcus (GBS) and Escherichia coli (E. coli). Signup and view all the answers

Explain the importance of assessing immunization status in children aged 6-36 months.

Children who are not fully immunized are at increased risk of serious bacterial infections and require vigilant evaluation. Signup and view all the answers

What criteria should guide the decision-making process regarding hospitalization for a febrile child?

The child's overall critical assessment, appearance, and need for antibiotics should guide the decision. Signup and view all the answers

How can maternal health affect the risk of neonatal sepsis?

Maternal fever or foul-smelling amniotic fluid can increase the risk of sepsis in the newborn. Signup and view all the answers

What is the significance of a detailed head-to-toe examination in febrile children?

It allows for the identification of potential sources of infection and guides further testing. Signup and view all the answers

Describe the relationship between age and severity of bacterial infections in children.

As age decreases, the severity and risk of serious bacterial infections increase in children. Signup and view all the answers

What symptoms should prompt the admission of a neonate with a temperature exceeding 38°C?

Any child under 1 month old with a temp over 38°C should be hospitalized. Signup and view all the answers

List at least three components of a full septic screen for a neonate.

CBC with differential, blood culture, and lumbar puncture. Signup and view all the answers

What combination of antibiotics is typically administered to infants suspected of bacterial infection?

Ampicillin and gentamicin, with possibly flucloxacillin for staph infections. Signup and view all the answers

What is the mortality rate associated with neonatal sepsis?

The mortality rate can be as high as 16%. Signup and view all the answers

Why might a lumbar puncture be necessary in the evaluation of febrile infants?

To assess for signs of meningitis, which may not present reliably in this age group. Signup and view all the answers

Which viral infection requires acyclovir treatment if suspected in a neonate with fever?

Herpes simplex virus (HSV) infection. Signup and view all the answers

What common bacterial pathogens are associated with infection in children aged 1-3 months?

Group B strep, Listeria monocytogenes, and Staphylococcus aureus. Signup and view all the answers

Explain why it is important to conduct further tests in children 1-3 months old presenting with fever.

Immediate investigation is crucial to rule out serious bacterial infections. Signup and view all the answers

What is the recommended action if a child's condition deteriorates while under hospital observation for fever?

Referral for immediate investigation is required. Signup and view all the answers

What is the significance of testing for concomitant viral infections in febrile infants?

Serious bacterial infections can occur even alongside viral infections in about 5% of cases. Signup and view all the answers

Study Notes

Fever Without Localizing Signs in Children

Fever is defined as an elevation of body temperature exceeding the normal daily variation, accompanied by an increase in hypothalamic set point.
Another definition is a temperature of more than 37.2°C before noon or 37.7°C after noon.
Fever without localizing signs refers to cases where the only sign is fever, and no other localized symptoms are present.
Fever without localizing signs in children accounts for about 70% of consultations to pediatricians.
The etiology, evaluation, and management of this condition depend on the child's age, as younger children are at higher risk of serious bacterial infection.

Objectives of Studying Fever in Children

Defining fever.
Evaluating and treating patients with fever.
Determining appropriate laboratory tests based on age group.
Identifying high-risk patients for sepsis.
Determining appropriate hospitalization criteria.
Establishing when empirical antibiotic therapy should be initiated.
Recognizing patterns of fever (intermittent, remittent, continuous).
Recognizing altered fever responses and situations where fever may not be present despite infection.
Understanding the factors associated with neonatal sepsis.
Identifying pathogens in neonates.

Definitions of Fever

Fever is defined as an elevation in body temperature that exceeds the normal daily variation. This increase is typically accompanied by a change in the hypothalamic set point.

Classifications of Fever

Normal body temperature ranges from 36.6°C to 37.2°C.
Low-grade fever ranges from 37.2°C to 37.8°C.
Moderate fever ranges from 37.8°C to 39.4°C.
High-grade fever ranges from 39.4°C to 40.5°C.
Hyperpyrexia is a temperature greater than 40.5°C.

Different Body Sites and Temperature Measurement

Rectal temperature is considered the standard and is 0.5-0.6°C higher than oral temperature.
Oral temperature is 0.8-1.0°C lower than rectal temperature.
Axillary temperature is 0.5-0.6°C lower than rectal temperature.
Tympanic temperature is 0.5-0.6°C lower than rectal temperature.

Physiology of Fever

Fever is not a disease but a body response to pyrogens (exogenous or endogenous).
Exogenous pyrogens include bacteria, viruses, fungi, and allergens.
Endogenous pyrogens (EPs) include immune complexes and lymphokines.
Major EPs include IL-1, IL-6, and TNF-α.

Pathogenesis of Fever

Pyrogens & destroyed cells activate macrophages.
Toxins trigger the release of IL-1β and cytokines, which affect the hypothalamus.
Prostaglandin E2 is produced in response to these cytokines, increasing body temperature.
Antipyretics like paracetamol and ibuprofen block the production of PGE2.

Benefits of Fever

WBCs function best in the range of 38-40°C, effectively fighting bacteria.
Fever boosts interferon activity, which hinders viral replication.
Fever directly inhibits the replication of Coxsackie and polio viruses.

Disadvantages of Fever

Hypercatabolism leads to nitrogen wastage, weight loss, and weakness.
Excessive sweating can cause electrolyte imbalance.
High fevers can lead to febrile convulsions and brain damage.
Circulatory overload and arrhythmia are possible complications.

Patterns of Fever

Intermittent fever: Fever that fluctuates, touching the baseline for periods during the day.
Remittent fever: Fever fluctuations above a baseline but never reaching the baseline within a 24-hour period.
Continuous fever: Fever that stays above the baseline without significant fluctuations within a 24-hour period.

Altered Fever Responses

Newborns, elderly individuals, patients with uremia, severe malnutrition or those on corticosteroids may not demonstrate fever despite infection.

Fever with Focus vs. Fever without Focus

Fever with focus: Fever associated with localized symptoms or signs (e.g., urinary tract infection, pneumonia, cough).
Fever without focus: Fever as the only sign, unrelated to any localized symptoms or signs.

Fever of Unknown Origin (FUO)

Characterized by persistent fever (≥ 38.3°C on multiple occasions) lasting for more than 3 weeks, with no identifiable cause after a week of extensive investigations.

Evaluation of Patients with Fever Without Localizing Signs/Symptoms

Step 1: Detailed history and physical examination, including head-to-toe assessment
Step 2: Specific lab tests and accessory studies, choosing appropriate tests
Step 3: Decision on next steps, including hospitalization or outpatient care, and need for antibiotics according to age and risk factors.

Neonatal Fever (up to one month)

Physical examination may not reliably detect serious infections.
Meningitis should be a strong clinical consideration in neonates with fever.
Common symptoms include hyperthermia or hypothermia, lethargy, poor feeding, vomiting, apnea, jaundice, dyspnea, hypotension, diarrhea, abdominal distension, bulging fontanelle, seizures, and bleeding.
Risk factors for sepsis include premature rupture of membranes, maternal fever, and foul-smelling amniotic fluid.
Common pathogens include Group B streptococcus, E. coli, Staphylococcus aureus, Klebsiellae, Listeria monocytogenes, fungi, and herpes simplex virus.
Full sepsis workup including CBC, CRP, electrolytes, blood cultures, urine cultures (via catheter or suprapubic aspiration), CXR, and possibly lumbar puncture is needed for suspected sepsis.

Children (One to three months old)

Majority of fevers are viral, but serious bacterial infections are possible.
Common pathogens include Group B strep, Listeria monocytogenes, H influenzae, Staphylococcus aureus, Salmonella, Meningococcus, and E. coli.
Low-risk criteria for children with fever but no other apparent symptoms: non-toxic appearance, no significant complications in medical history, normal physical examination, and normal lab tests.
Hospitalization and broad-spectrum antibiotics with empirical therapy are crucial for high-risk cases.
Reassurance and symptomatic care are appropriate for low-risk situations.

Children (Three to 36 months old)

Fever in this age range is often viral, with a 30% chance of no localized infection symptoms.
Common pathogens include Streptococcus pneumoniae, Meningococcus, Salmonella, and HiB.
Low-risk cases might be managed with symptomatic treatment and outpatient follow-up.
High-risk criteria include unwell or toxic appearance, WBC greater than 15,000 or less than 5,000, and any positive findings on various investigations.
Hospitalization and parental antibiotics are necessary for potentially severe cases.

Antipyretics

Acetaminophen is a first-line antipyretic for fever and is generally well-tolerated with minimal side effects.
Pediatric dose is 10-15 mg/kg every 4-6 hours.
Adult dose is 650 mg every 4 hours.
Acetaminophen can be hepatotoxic in high doses and can upset the stomach.
Other antipyretics include ibuprofen and mefenamic acid.

Important Considerations

Avoid giving aspirin to children under 18 years old due to the risk of Reye's syndrome.
Tepid sponge baths (27°C) can help reduce fever.
Maintaining a comfortable room temperature is recommended.

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Description

This quiz covers essential aspects of fever and its management in children, including definitions, physiological mechanisms, and treatment options. Key topics include the role of pyrogens, monitoring fever, and guidelines for managing high-risk pediatric patients. Test your knowledge on when to initiate antibiotic therapy and the significance of a thorough sepsis workup.