Ultrasound measurement of appendiceal diameter for identifying neonatal appendicitis

Neonatal appendicitis is a potentially fatal condition due to non-specific symptoms and a lack of reliable diagnostic criteria.

This study evaluates the utility of ultrasound-measured appendiceal outer diameter in distinguishing neonatal appendicitis from other conditions mimicking neonatal appendicitis.

A retrospective matched case-control study was conducted on neonates aged 0-28 days. Cases with surgically confirmed appendicitis were compared to controls with suspected acute abdomen or necrotizing enterocolitis (NEC). Two experienced ultrasound physicians independently measured the maximum appendiceal outer diameter. Sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC) were calculated.

Twenty-one cases and 84 controls were included. The median appendiceal outer diameter was significantly larger in the appendicitis group (4.8 mm) compared to the suspected acute abdomen group (2.6 mm) and the NEC group (3.3 mm) (P<0.001). An appendiceal diameter cutoff of ≥ 3.5 mm yielded an AUC of 0.89 (95% confidence interval [CI], 0.82-0.97), with a sensitivity of 90.5% and specificity of 72.6% for diagnosing neonatal appendicitis. Subgroup analysis showed excellent diagnostic accuracy in differentiating appendicitis from other suspected acute abdominal conditions (AUC=0.95; 95% CI, 0.90-1.00).

Ultrasound-measured appendiceal diameter is a valuable tool for diagnosing neonatal appendicitis, with a cutoff of ≥ 3.5 mm providing high diagnostic accuracy.