Utility of Pyloric Length Measurement for Detecting Severe Metabolic Alkalosis in Infants with Hypertrophic Pyloric Stenosis.

Purpose: Infantile hypertrophic pyloric stenosis (IHPS) is a common gastrointestinal disease in neonates and hypochloremia metabolic alkalosis is a typical laboratory finding in affected patients. This study aimed to analyze the clinical characteristics of infants with IHPS and evaluate the association of clinical and laboratory parameters with ultrasonographic findings.

Methods: Infants diagnosed with IHPS between January 2017 and July 2022 were retrospectively evaluated.

Results: A total of 67 patients were included in the study. The mean age at diagnosis was 40.5±19.59 days, and the mean symptom duration was 11.97±9.91 days. The mean pyloric muscle thickness and pyloric canal length were 4.87±1.05 mm and 19.6±3.46 mm, respectively. Hyponatremia and metabolic alkalosis were observed in five (7.5%) and 36 (53.7%) patients, respectively. Serum sodium (p=0.011), potassium (p=0.023), and chloride levels (p=0.015) were significantly lower in patients with high bicarbonate levels (≥30 mmol/L). Furthermore, pyloric canal length was significantly higher in patients with high bicarbonate levels (p=0.015). To assess metabolic alkalosis in IHPS patients, the area under the receiver operating characteristic curve of pyloric canal length was 0.910 and the optimal cutoff value of the pyloric canal length was 23.5 mm.

Conclusion: We found a close association between laboratory and ultrasonographic findings of IHPS. Clinicians should give special consideration to patients with pyloric lengths exceeding 23.5 mm and appropriate fluid rehydration should be given to these patients.