Electrographic seizures are associated with brain injury in newborns undergoing therapeutic hypothermia
- Divyen K Shah1,2,
- Courtney J Wusthoff3,
- Paul Clarke4,
- John S Wyatt5,
- Sridhar M Ramaiah4,
- Ryan J Dias1,
- Julie-Clare Becher6,
- Olga Kapellou7,
- James P Boardman6,8
- 1Royal London Hospital, London, UK
- 2Barts and the London Medical School, London, UK
- 3Stanford University School of Medicine, Palo Alto, California, UK
- 4Norfolk and Norwich University Hospitals, Norwich, UK
- 5University College London, London, UK
- 6Royal Infirmary of Edinburgh, Edinburgh, UK
- 7Homerton University Hospital, London, UK
- 8MRC/University of Edinburgh Centre for Reproductive Health, Edinburgh, UK
- Correspondence to Dr Divyen K Shah, Barts and the London Childrens Hospital, Neonatology, Royal London Hospital, Whitechapel, London E1 1BB, UK;
- Received 9 September 2013
- Revised 19 December 2013
- Accepted 1 January 2014
- Published Online First 17 January 2014
Objective Seizures are common among newborns with hypoxic-ischaemic encephalopathy (HIE) but the relationship between seizure burden and severity of brain injury among neonates receiving therapeutic hypothermia (TH) for HIE is unclear. We tested the hypothesis that seizure burden is associated with cerebral tissue injury independent of amplitude-integrated EEG (aEEG) background activity.
Study design Term neonates undergoing 72 h of TH at four centres were selected for study if they had continuous aEEG and MRI. The aEEG with corresponding 2-channel raw EEG (aEEG/EEG), was classified by severity of background and seizure burden; MR images were classified by the severity of tissue injury.
Results Of 85 neonates, 52% had seizures on aEEG/EEG. Overall, 35% had high seizure burden, 49% had abnormal aEEG background in the first 24 h and 36% had severe injury on MRI. Seizures were most common on the first day, with significant recurrence during and after rewarming. Factors associated with severe injury on MRI were high seizure burden, poor aEEG background, 10 min Apgar and the need for more than one anticonvulsant. In multivariate logistic regression, high seizure burden was independently associated with greater injury on MRI (OR 5.00, 95% CI 1.47 to 17.05 p=0.01). Neither aEEG background, nor 10 min Apgar score were significant.
Conclusions Electrographic seizure burden is associated with severity of brain injury on MRI in newborns with HIE undergoing TH, independent of degree of abnormality on aEEG background. Seizures are common during cooling, particularly on day 1, with a significant rebound on day 4.