Herpes simplex virus infection in young infants during 2 decades of empiric acyclovir therapy

To describe the clinical presentation of HSV-infected young infants and to seek distinctive features that could permit a targeted approach to empiric use of acyclovir.

Case study of neonatal HSV during a 22-year period of an institutional strategy of consistent use of acyclovir empirically in all infants with onset of an illness at ≤ 21 days of age for which antibiotics were given empirically. Multiple sources were used to optimize HSV case data, and to estimate the rate of HSV infection in empirically treated infants.

A total of 32 infants with perinatally acquired HSV infection were identified. All received acyclovir empirically at admission. At presentation, 50% of infants had only nonspecific complaints, which was fever in 75%. After testing, 75% of infants with HSV had central nervous system (CNS) infection, including 40% who presented with mucocutaneous lesions, 83% with seizures, and 94% with nonspecific complaints. Cerebrospinal fluid (CSF) polymerase chain reaction confirmed CNS infection in 16 of 22 (73%) patients tested. Cultures of mucocutaneous lesion yielded HSV in 8 of 10 cases, but culture of CSF was negative in all 26 cases tested, and screening cultures of unaffected mucosal sites were the only HSV-confirmatory test in a single patient. Laboratory and CSF findings were not distinctive in patients with HSV. Age of ≤ 21 days at onset of symptoms captured 90% of all infants with HSV and 94% of those with nonspecific complaints. An estimated 1.3% of empirically treated patients had HSV infection.

Early manifestations of perinatally acquired HSV are frequently nonspecific, yet CNS infection is common. Empiric acyclovir strategy narrowly restricted to infants with onset of illness at ≤ 21 days of age, who would receive antibiotics empirically, captured 90% of HSV cases and anticipated a rate of HSV CNS infection similar to that of bacterial meningitis.