Higher admission serum total carbon dioxide is independently associated with early seizure recurrence in children with benign convulsions with mild gastroenteritis.

BACKGROUND

Readily accessible biomarkers for early seizure recurrence in benign convulsions with mild gastroenteritis (CwG) are lacking. We evaluated whether admission serum total carbon dioxide (TCO2), a routine venous surrogate for bicarbonate, predicts seizure recurrence within 48 h in children with CwG.

METHODS

This retrospective study included children aged 6 months to 6 years diagnosed with CwG (2020-2026). Multivariable logistic regression evaluated the association between admission venous TCO2 and seizure recurrence within 48 h, adjusting for age and anticonvulsant use. Model performance underwent bootstrap internal validation. TCO2/bicarbonate concordance was assessed in a paired subset.

RESULTS

Of 86 children (median age 14.5 months), 23 (26.7%) experienced recurrence. Median TCO2 was higher in the recurrence group (17.4 vs. 15.1 mmol/L, P = 0.007). In multivariable analysis, higher TCO2 (odds ratio 1.235, 95% confidence interval 1.053-1.448; P = 0.009) and younger age (P = 0.016) were independently associated with recurrence. The optimism-corrected area under the curve was 0.710, calibration slope was 0.748, and Brier score was 0.164. A TCO2 cutoff of 16.25 mmol/L yielded 78.3% sensitivity, 61.9% specificity, and 88.7% negative predictive value. In 29 paired samples, venous TCO2 and arterial bicarbonate were strongly correlated (r = 0.966, P < 0.001).

CONCLUSIONS

Higher admission serum TCO2 was independently associated with early seizure recurrence in CwG. As a readily accessible venous biomarker, TCO2 may represent a candidate marker for bedside risk stratification to guide observation. These findings are hypothesis-generating, and external validation in prospective cohorts is warranted.