Introduction: Cerebral edema (CE) is a rare but life-threatening consequence of diabetic ketoacidosis (DKA), presenting clinically in 2% of cases and sub-clinically in over half. Neuroimaging is impractical for frequent monitoring and carries risks related to transport, radiation, and sedation. We investigated whether serial bedside measurements of optic nerve sheath diameter (ONSD) via US and Neurological Pupil index (NPi) via infrared pupillometry can detect and track CE in pediatric DKA. We hypothesized that ONSD would be elevated and NPi depressed in patients with CE, and both would normalize as DKA resolves. Methods: We performed a prospective observational study of children (0–17 years) admitted to the PICU with DKA. Serial neurologic exams, ophthalmic US, and pupillometry were performed every 8 hours until resolution of DKA. At each assessment, GCS, pupillary light reflex, blood pH, and bicarbonate levels were recorded. Results: Twelve patients (67% new diagnoses) were included; 4 had no encephalopathy, 6 had mild, and 2 had moderate. The average presenting pH was 7.04(SD:0.14), bicarbonate 5.8(1.6), and glucose 409(415). Median ONSD was 5.75mm at presentation and 5.59mm at resolution of DKA with an average decrease of 0.125mm(0.31). Five patient’s NPi decreased, 5 increased, 1 was unchanged and 1 was unable to be measured. The average change in NPi was an increase of 0.06(0.38). Conclusions: This preliminary data suggests that ONSD changes show a promising trend correlating with resolution of CE and DKA, while NPi fluctuations do not appear to correlate. Additional enrollment in this study and other larger studies are needed to define diagnostic thresholds and validate this modality to guide timely identification of CE and possibly influence interventions.
Morgan et al. (Sun,) studied this question.