The AAP recommends that a lumbar puncture be performed in any infant who:

• A. Has worsening respiratory distress syndrome
• B. Is at high-risk and being treated for rule out sepsis but is otherwise healthy-appearing
• C. Does not respond to antibiotic therapy
• D. Is asymptomatic

Answer: (C)

Evaluating for meningitis in infants hinges on recognizing when the infection may be hidden in the CNS and not fully cleared by initial therapy. If an infant is started on empiric antibiotics for suspected sepsis or meningitis but does not show clinical improvement, a lumbar puncture is indicated to examine the cerebrospinal fluid. CSF analysis confirms or rules out meningitis, and findings guide the choice of antibiotics, duration of therapy, and whether a different regimen is needed. Meningitis in young infants can be subtle and may not respond promptly to treatment if the pathogen is present in the CSF or if antibiotic penetration into the CSF is insufficient, so obtaining CSF helps tailor management beyond what blood work or clinical signs alone provide. This is not indicated solely by respiratory status, lack of symptoms, or a high-risk but otherwise well-appearing scenario without treatment failure.