Predominant area of brain lesions in neonates with herpes simplex encephalitis

Kidokoro H, de Vries LS, Ogawa C, Ito Y, Ohno A, Groenendaal F, Saitoh S, Okumura A, Ito Y, Natsume J. Predominant area of brain lesions in neonates with herpes simplex encephalitis. J Perinatol. 2017 Jul 20. doi: 10.1038/jp.2017.114.[Epub ahead of print]

Abstract

OBJECTIVE:

Nonspecific manifestations and a varied distribution of brain lesions can delay the diagnosis of herpes simplex encephalitis (HSE) in neonates. The aim of this study was to report predominant brain lesions in neonatal HSE, and then to investigate the association between pattern of predominant brain lesions, clinical variables and neurodevelopmental outcome.

STUDY DESIGN:

A multicenter retrospective study was performed in neonates diagnosed with HSE between 2009 and 2014. Magnetic resonance (MR) images, including diffusion-weighted images, were obtained in the acute and chronic phase.

RESULTS:

Three predominant areas of brain injury could be defined based on characteristic MRI findings in 10 of the 13 infants (77%). The inferior frontal/temporal pole area was involved in five (38%) patients. The watershed distribution was present in six (46%) patients. Four (31%) infants involved the corticospinal tract area. No significant association was found between any predominant distribution of brain lesion pattern and sex, country, viral type or viral load. However, the corticospinal tract involvement was significantly associated with motor impairment (P=0.045).

CONCLUSION:

Three predominant areas of brain lesion could be recognized in neonatal HSE. Recognition of those areas can improve prediction of neurodevelopmental outcome.

Characteristic distribution of brain lesions. The inferior frontal and temporal pole distribution (upper panels: a–c). The inferior frontal and anterior temporal lobes are symmetrically involved, as shown on a diffusion-weighted image taken 3 days after disease onset (a). T2-weighted MR images exhibit high signal intensity at 2 weeks (b) and cystic evolution of the anterior temporal lesions at 2 months after onset (c) (Supplementary Table S1 online, patient 10). The watershed distribution (middle panels: d–f). Scattered, punctate cortical lesions (termed 'stardust appearance') in the watershed areas on diffusion-weighted imaging (DWI) taken at 5 days after disease onset (a and b) and on T2-weighted MR images taken at 58 months (c) (Supplementary Table S1 online, patient 1). The corticospinal tract (CST) distribution (lower panels: g–i). Bilateral CST involvement, including posterior limbs of internal capsule, is evident on DWI at 6 days after disease onset (g and h). Note that the posterior watershed area is also present (i). Cystic evolution is seen in the occipital watershed regions on a T2-weighted MR image taken 20 days after disease onset (Supplementary Table S1 online, patient 7).