Infants or young children who have a fever with no obvious source of infection present a diagnostic dilemma. Health care providers see these patients on a daily basis. As many as 20% of childhood fevers have no apparent cause.[1] A small but significant number of these patients may have a serious bacterial infection; the risk is greatest among febrile infants and children younger than 36 months, making proper diagnosis and management important. Physical examination and patient history do not always identify patients with occult bacteremia or serious bacterial infection. Serious infections that are not recognized promptly and treated appropriately can cause significant morbidity or mortality.
This article focuses primarily on infants and young children aged 2-36 months and reflects the significant changes in the care of the febrile infant and child over the past 10 years. The article Fever in the Young Infant addresses the diagnosis and treatment of febrile infants younger than 2 months.
Fever is defined as a rectal temperature that exceeds 38°C (100.4°F). Direct the initial evaluation of these patients toward identifying or ruling out serious bacterial infections (SBI), most commonly urinary tract infections. The following questions are important to consider:
A great deal of time and effort has been spent on research to help identify the febrile infant and young child with a serious bacterial infection. However, evaluation and treatment of febrile infants and young children vary, despite nationally published treatment guidelines.
Note also, this article primarily addresses children who are completely immunized, and in particular who have received full Hib and PCV7 vaccine series. Unimmunized children are at higher risk for bacteremia, pneumonia, and other SBI's.
Meningitis, pneumonia, urinary tract infection (UTI), and bacteremia are serious etiologies of fever in infants and young children.
Neonates' immature immune systems place them at greater risk of systemic infection. Hematogenous spread of infection is most common in this age group or in patients who are immunocompromised or unimmunized. For these same reasons, infants who have a focal bacterial infection have a greater risk of developing metastatic infection or bacteremia.
The following are among the most common bacterial etiologies of serious bacterial infection in this age group:
Historically, approximately 2.5-3% of highly febrile children younger than 3 years have occult bacteremia, which is typically caused by S pneumoniae.[2] The advent of conjugate pneumococcal vaccine has resulted in a decrease in pneumococcal occult bacteremia and other disease.[3] Viral infections are common in the young child as well[4] ; however, exclude serious bacterial infection prior to assuming a viral etiology for the fever.[5]
United States
Fever accounts for 10-20% of pediatric visits to health care providers.
Patients with no easily identified source of infection have a small but significant risk of a serious bacterial infection. If not recognized and treated appropriately and promptly, this can cause morbidity or mortality.
There is no racial difference in incidence of fever.
There is no difference in incidence of fever in males vs. females.
This article focuses on the diagnosis and treatment of febrile children aged 2-36 months.
Obtaining an accurate history from the parent or caregiver is important when assessing fever without a focus; the history obtained should include the following information:
While performing a complete physical examination, pay particular attention to assessing hydration status and identifying the source of infection.[6, 7] Physical examination of every febrile child should include the following:
Record vital signs.
Measure pulse oximetry levels.
Record an accurate weight on every chart.
During the examination, concentrate on identifying any of the following:
For all patients aged 2-36 months, management decisions are based on the degree of toxicity and the identification of serious bacterial infection.
The Yale Observation Scale is a reliable method for determining degree of illness.[8, 9] It consists of 6 variables: quality of cry, reaction to parent stimulation, state variation, color, hydration, and response. A score of 10 or less has a 2.7% risk of serious bacterial infection. A score of 16 or greater has a 92% risk of serious bacterial infection. It is important to remember that this scale was validated in the occult bacteremia era, prior to widespread pneumococcal conjugate vaccination.
Regarding the height of temperature, Hoberman et al found that 6.5% of patients with a temperature of 39.0°C (102.2°F) or more had a urinary tract infection (UTI) and that white females with that temperature had a 17% incidence of UTI.[10]
Table. Summary of the Yale Observation Scale
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Several common bacteria cause serious bacterial infections, including the following:
Recommended laboratory studies for children with fever without a focus are based on the child's appearance, age, and temperature.[12]
Begin intravenous (IV) or intramuscular (IM) antibiotic administration for all infants who appear ill once urine and blood specimens are obtained.
Perform the following for children who do not appear toxic:
Perform the following for children who appear toxic:
See the list below:
Chest radiography is part of any thorough evaluation of a febrile child.[14]
Chest radiography is indicated when the patient has tachypnea, retractions, focal auscultatory findings, or oxygen saturation level in room air of less than 95%.
Although viral etiologies are considered the cause of most pediatric pneumonias, establishing a viral or bacterial etiology may be challenging.
For children with fever without a focus who appear ill, conduct a complete evaluation to identify occult sources of infection. Follow the evaluation with empiric antibiotic treatment and admit the patient to a hospital for further monitoring and treatment pending culture results. Because children presenting with fever and leukopenia are also a concern, consider leukocytosis and leukopenia in making decisions about empiric antibiotic therapy. According to a recent study by Gomez et al, isolated leukopenia, especially in children without leukocyturia suggestive of a UTI, may not be a significant risk factor for SBI and viral etiologies may be considered more strongly.[17]
Patients aged 2-36 months may not require admission if they meet the following criteria:
Treatment recommendations for children with fever without a focus are based on the child's appearance, age, and temperature.
For children who do not appear toxic, treatment recommendations are as follows:
For children who appear toxic, treatment recommendations are as follows:
The need to consult with specialists depends on the specialty of the physician who initially evaluated the patient and the ultimate source of fever. Typically, general pediatricians easily manage febrile infants on both an inpatient and outpatient follow-up basis.
Patient tolerance is the only restriction on diet. Physicians should monitor intake and output as an indication of the patient's status because these measurements may provide the first evidence of a disturbance that indicates illness.
Patient tolerance also determines activity level, which should be monitored for changes (eg, lethargy, irritability).
Treatment with antipyretics is somewhat controversial because fever is a defensive response to infection (Sullivan, 2011). Base the decision to treat a fever without a focus on age, presentation, and laboratory results. If antibiotics are administered empirically, close follow-up is required. Parenteral antibiotics are the drugs of choice.
Clinical Context: Third-generation cephalosporin with broad-spectrum, gram-negative activity; lower efficacy against gram-positive organisms; higher efficacy against resistant organisms; arrests bacterial growth by binding to one or more penicillin-binding proteins.
Clinical Context: For septicemia and treatment of gynecologic infections caused by susceptible organisms. Arrests bacterial cell wall synthesis, which, in turn, inhibits bacterial growth. Third-generation cephalosporin with gram-negative spectrum. Lower efficacy against gram-positive organisms. Useful in pediatric infections as an alternative to ceftriaxone in infants in the first month or two of life, in whom bilirubin displacement from protein-binding sites by the latter antibiotic may be harmful.
Clinical Context: Drug combination of beta-lactamase inhibitor with ampicillin. Covers skin, enteric flora, and anaerobes. Not ideal for nosocomial pathogens.
Empiric antimicrobial therapy must be comprehensive and should cover likely pathogens in the clinical setting.
Clinical Context: Among the few NSAIDs indicated for reduction of fever; produces anti-inflammatory, antipyretic, and analgesic effects by inhibiting prostaglandin synthesis.
Clinical Context: Reduces fever by acting directly on hypothalamic heat-regulating centers, which increases dissipation of body heat via vasodilation and sweating.
These agents inhibit central synthesis and release of prostaglandins that mediate the effect of endogenous pyrogens in the hypothalamus and, thus, promote the return of the set-point temperature to normal.
See the list below:
See the list below:
See the list below:
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See the list below:
Observation Items 1 (Normal) 3 (Moderate Impairment) 5 (Severe Impairment) Quality of cry Strong with normal tone or contentment without crying Whimpering or sobbing Weak cry, moaning, or high-pitched cry Reaction to parent stimulation Brief crying that stops or contentment without crying Intermittent crying Continual crying or limited response Color Pink Acrocyanotic or pale extremities Pale or cyanotic or mottled or ashen State variation If awake, stays awake; if asleep, wakes up quickly upon stimulation Eyes closed briefly while awake or awake with prolonged stimulation Falls asleep or will not arouse Hydration Skin normal, eyes normal, and mucous membranes moist Skin and eyes normal and mouth slightly dry Skin doughy or tented, dry mucous membranes, and/or sunken eyes Response (eg, talk, smile) to social overtures Smiling or alert (< 2 mo) Briefly smiling or alert briefly (< 2 mo) Unsmiling anxious face or dull, expressionless, or not alert (< 2 mo)