Plasma sodium as a predictor of perforation in acute appendicitis: A prospective multi-centre study.

BACKGROUND

Non-operative treatment for acute appendicitis (AA) in children has gained acceptance as an alternative to surgery in selected cases. Accurate preoperative differentiation between perforated and non-perforated AA is increasingly important, as the former requires emergency surgery while the latter may be managed conservatively. Previous research has suggested that low plasma sodium concentration (P-Na) may serve as a reliable predictor of perforation. This study aimed to evaluate the association between P-Na and appendiceal perforation in a prospective, multicentre paediatric cohort.

METHODS

Previously healthy children, aged 1-15 years, presenting with suspected AA who subsequently underwent appendectomy were enrolled at five paediatric surgical centres (Stockholm, Oslo, Berlin, Odense and Cape Town). Blood sampling on admission included concentration of C-reactive protein, plasma sodium concentration, white blood cell count and neutrophil count.

RESULTS

451 children met the inclusion criteria. Mean plasma sodium concentration on admission was lower in children with perforated AA as compared to non-perforated AA, mean 133.6 (standard deviation (SD) 4.0) mmol/l and 138.2 (SD 2.7) mmol/l respectively. A cut-off value of P-Na > 136 mmol/l resulted in an odds ratio of 0.11 (95% CI 0.07-0.17) for perforation. In a multivariate logistic regression analysis CRP and P-Na, respectively, were the strongest predictors of perforation. Combining the two resulted in an area under the curve of (AUC) of 0.86 in discriminating perforated AA from non-perforated AA.

CONCLUSIONS

In this large, prospective, multicentre study, low P-Na was independently associated with an increased risk of perforated AA in children. The predictive value improved when combined with CRP.