Optic Nerve Sheath Diameter Ultrasonography in Pediatric Patients with Diabetic Ketoacidosis

Objectives: Subclinical cerebral edema has been reported in pediatric patients with type 1 diabetes and diabetic ketoacidosis (DKA) through magnetic resonance imaging. Ultrasonography of the optic nerve sheath diameter (ONSD) has been used to evaluate intracranial pressure. The objective of this study was to examine the utility of ONSD ultrasonography to evaluate intracranial pressures in children with DKA. Methods: This prospective cohort evaluated pediatric patients who presented to the emergency department of the Children's Hospital at the University of Manitoba with DKA within 3 hours of initial treatment. A pediatric bedside neurologic evaluation tool for cerebral edema was utilized 1) within the first hour of the intravenous fluid initiation (t = 0 hr); 2) 8 hours after initiation of treatment (t = 8 hr); and 3) at hours after presentation (t=24 hr). At each time interval, 3 images of the patients' ONSDs were scanned by an 11 MHz linear array transducer. Increased intracranial pressure was considered in all patients whose mean ONSDs were >4.5 mm. Results: We evaluated 7 patients, aged 4 to 17 years. No patients were clinically assessed as having cerebral edema. Overall, no significant differences emerged among the 3 time points (t = 0 vs. t = 8 hr; t = 0 vs. t = 24 hr; t = 8 vs. t=24 hr) (all p>.216). Effect sizes were small at 0.14 (t = 0 vs. t=8 hr); 0.27 (t = 8 vs. t = 24 hr); and 0.07 (t = 0 vs. t = 24). Conclusions: Although not statistically significant, subtle changes in intracranial pressure may have been detected with ONSD ultrasonography in pediatric patients with DKA.