Evaluation of Fever of Unknown Origin in an Infant: Can a Case Be Made for Ultrasound of the Head as a Second-Tier Test for Meningitis?

Although meningitis in neonates has been less prevalent since the initiation of prevention measures such as maternal group B streptococcal (GBS) screening and intrapartum antibiotic prophylaxis, it remains on the differential diagnosis for causes of prolonged fever or fever of unknown origin (FUO). Although not always present, fever is a potential symptom of meningitis in neonates and infants, in whom other signs and symptoms of meningitis are not as easily identifiable as in older children. Cerebrospinal fluid (CSF) analysis and culture remain the gold standard for diagnosis of meningitis, but ancillary testing, such as head imaging, can aid in the evaluation of the patient. We present a case of a two-month-old male child in which a head ultrasound via the anterior fontanelle was able to aid in the diagnosis of meningitis.