Does phototherapy cause epilepsy?

A previous Danish study suggested an association between phototherapy in the neonatal period and a seizure diagnosis in childhood. Like many such studies the analysis was not adjusted for the bilirubin concentration, so if the association is true it might be because of confounding by severity, that is babies with higher bilirubins being more likely to get phototherapy, and potentially the link to seizures being higher bilirubins, rather than the phototherapy itself.

Other suggested associations of phototherapy, including childhood cancers, have also been made, but that association largely disappears after controlling for bilirubin concentrations.

In this new publication (Newman TB, et al. Childhood Seizures After Phototherapy. Pediatrics. 2018;142) the Kaiser Permanente Epidemiology group have used administrative databases and the electronic health records to compare diagnoses of epilepsy and prescriptions of anti-epileptic drugs between infants with and without phototherapy, after correcting for the serum bilirubin concentration. This analysis shows a statistically significant association even after correction. The increased risk of seizures in association with phototherapy was small, between 2 and 7 per 1,000 babies treated, but as they note, in situations where there is no evidence of benefit, i.e. a probability of exchange transfusion that is extremely low, then even a small increase in risk is better to avoid.

They also point to a new guideline promoted by a consensus group from the Northern California Neonatal Consortium. Because of the rarity of kernicterus, and the potential small risks of phototherapy, they took the AAP guidelines (this would apply to the very similar CPS guidelines, of which I was one author) divided them up by individual weeks of completed gestational age, and by whether there were neurotoxicity risk factors or not (that is hemolysis, sepsis, acidosis, hypoalbuminemia or “clinical instability”), and then added between 0 and 3 mg/dl (that is 0 to 51 micromol/L in modern units) to create new curves. You can access their on-line calculator here, or you could print out the new curves here or you can read the whole document (as a downloadable Microsoft Word file)

I am not convinced about the risk of seizures from these data, but they certainly support a possible link, and safe ways to reduce phototherapy use are probably in the best interest of families and babies.

About Keith Barrington

I am a neonatologist and clinical researcher at Sainte Justine University Health Center in Montréal
This entry was posted in Neonatal Research. Bookmark the permalink.

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