“[Infant] with background of gastroschisis and ileostomy in situ. Under follow-up with gastroenterology [tertiary], paediatric surgeons [tertiary] and general paediatrics [at local hospital]. Previously receiving sodium supplements. Presented to ED with vomiting, loose stool, lethargy and weight loss. Na+ (sodium level) 97 on gas in ED. Sodium correction started in ED and patient moved to CICU for ongoing management. Sodium corrected over the next 48hrs. 48hrs later was found to have altered neurological status with irritability, lethargy and weakness. MRI subsequently showed oedema of the basal ganglia and extrapontine myelinolysis, consistent with being secondary to fluid and electrolyte shifts. Minimal improvement in neurological status at this point in time (further 48hrs later)."

We have seen several reports of this in PSU of late. The balance is between correcting the sodium level quickly enough initially to prevent or terminate seizures and then correcting the remaining deficit slowly to avoid this syndrome of myelinolysis. It has been the subject of a recent NEJM editorial. [1]

1. Ayus, JC; Moritz, ML. Editorial: Hyponatremia Treatment Guidelines - Have They Gone Too Far? NEJM Evid, 2023; 2(4) (NB: paywall)