White matter lesions in term infants with neonatal encephalopathy: Correlation with later scans and neurodevelopmental outcome

Abstract

Background: The commonest brain abnormality after perinatal hypoxic–ischaemia and neonatal encephalopathy (NE) is damage to the basal ganglia (BGT). However there are infants who escape this damage but have abnormally appearing white matter (WM). The long-term outcome of these children has not been well defined. Aim: To evaluate, in term infants with NE and abnormally appearing WM but normal BGT on neonatal MRI scan, the evolution of the scans in the first 1–2 years and the relation of the imaging findings to neurodevelopmental outcome at 2–4 years. Subjects/Methods: From a cohort of 270 term infants with perinatal asphyxia and NE (without evidence of systemic infection, a metabolic, or a congenital disorder), born at or referred to the Hammersmith Hospital, London (1991–2000) 46 infants had normally appearing BGT but abnormal WM on neonatal scans; 18 infants had normal scans. Follow-up scans were obtained in 57 infants. Griffiths developmental scales, standardized neurological examination and HC, evidence of cerebral palsy (CP), visual, hearing, language, feeding and behavioural problems) was obtained in all infants. Parental and ethical permission from the Hammersmith Hospital REC was obtained. Results: Median (range) of gestation was 40.1 weeks (36– 42 weeks), birth weight 3.26 kg (2.0–4.82 kg), head circumference (HC) 35.0 cm (31–39.1 cm), Apgar scores at 1/5 min was 2 (0–9)/6 (0–10), pH 6.97 (6.56–7.37). 38 infants (59%) were male; 26 had Sarnat stage I and 38 had stage II NE. WM abnormality on neonatal scans was mild in 20, moderate in 14, severe in 9 and severe with haemorrhage in 3; 18 infants had normal scans. Follow up scans were normal in 18, mildly abnormal in 18, moderate in 9, severe in 8 and severe with marked tissue loss in 4. Neonatal and later grading of scans remained the same 67%; improved in 12% and deteriorated in 21% by one grade. There was no difference in the perinatal data bar HIE staging between the infants in the different WM groupings at birth or follow-up. Mean (range) DQ at a median age of 3 years in children with normal WM was 109 (88–125), with mild WM 106 (85–124), moderate WM 88 (40–126), severe WM 71 (45–95) severe with haemorrhage 50 (40–60). In contrast, the neurological exam score was only low in the severe WM group. Six children had CP but only two were not independently ambulant. Followup scan abnormalities included a PVL-like appearance, reduced thalamic size and cortical abnormality. The more severe follow up scans were associated with CP, poor head growth, early feeding problems, language delay, squint and behavioural difficulties. Discussion: Follow-up scans of infants with NE show that neonatal WM abnormality may lead to significant long-term problems. Early and late scans correlate but the change in grading in 33% suggests that external factors may influence outcome. Outcome at 2–4 years can be significantly abnormal in those with moderate and severe scan abnormality. Despite few major motor problems these infants require prolonged follow up and considerable support [1]. Reference [1] Marlow N, et al. Arch Dis Child 2005;90:F380–7.