How to manage a 2-month-old patient with fever (febrile illness) and high white blood cell (WBC) count?

From the Guidelines

A 2-month-old with fever and elevated white blood cell count requires immediate medical attention and hospitalization. The initial management includes a full sepsis workup with blood cultures, urine cultures, and possibly cerebrospinal fluid analysis through lumbar puncture. Empiric antibiotic therapy should be started promptly, typically with ampicillin (50 mg/kg IV every 6 hours) and gentamicin (4 mg/kg IV every 24 hours) or cefotaxime (50 mg/kg IV every 8 hours) to cover common pathogens including Group B Streptococcus, Escherichia coli, and Listeria monocytogenes, as suggested by the most recent study 1. Antipyretics such as acetaminophen (10-15 mg/kg every 4-6 hours) can be used to manage fever. Careful monitoring of vital signs, hydration status, and clinical response is essential. Laboratory tests should include complete blood count with differential, C-reactive protein, and procalcitonin if available. Infants this young have immature immune systems and are at high risk for serious bacterial infections, including bacteremia, urinary tract infections, and meningitis. The combination of fever and elevated WBC count significantly increases this risk, necessitating aggressive evaluation and treatment. Some key points to consider in management:

• The risk of cerebrospinal fluid pleocytosis is higher in infants with a temperature greater than 38.4 C and WBC count greater than 6,100/mL, as found in the study 1.
• The study 1 highlights the importance of considering urinary tract infections in febrile infants, but the most recent and relevant guidance for the specific case of a 2-month-old with fever and elevated WBC comes from 1.
• The use of empiric antibiotic therapy is supported by older studies 1, but the choice of antibiotics and the approach to management should be guided by the most current evidence and clinical guidelines, which emphasize the importance of covering common pathogens and monitoring for clinical response. Antibiotics should be continued until culture results are available, typically 48-72 hours, and then narrowed or discontinued based on these results and clinical improvement.

From the Research

Management of Febrile Infants

To manage a 2-month-old patient with fever and high white blood cell (WBC) count, consider the following:

• The white blood count is commonly used in the evaluation of the febrile infant without a focal source of infection 2.
• An elevated WBC affects physician management by causing more tests to be ordered and by influencing some physicians to choose more aggressive management strategies 2.
• Neutrophilic leukocytosis is often used in the diagnosis of infection despite its lack of specificity in situations of stress 3.
• Eosinopenia represented the most efficient parameter of the WBC count for the diagnosis of urinary and biliary tract infections 3.

Diagnostic Approach

When evaluating a febrile infant, consider:

• Obtaining blood, urine, and cerebrospinal fluid cultures 4.
• Using clinical screening criteria to identify infants with serious bacterial infections, although these criteria may not enable discrimination between infants with and those without serious bacterial infections 4.
• Monitoring the patient's condition closely and adjusting the management plan as needed 4.

Treatment Options

For febrile infants with high WBC counts, treatment options may include:

• Intramuscular administration of ceftriaxone, which has been shown to be effective in outpatient treatment of febrile infants 28 to 89 days of age 4.
• Hospital admission for further evaluation and treatment, particularly if the infant appears ill or has a high risk of serious bacterial infection 2, 4.
• Close follow-up and monitoring to ensure the patient receives appropriate antimicrobial therapy and to detect any potential complications 4.