Risk factors for unsuccessful atropine therapy in hypertrophic pyloric stenosis.

Intravenous atropine (IA) for infantile hypertrophic pyloric stenosis (IHPS) is a good alternative to pyloromyotomy but has not been broadly accepted. The lower success rate is one of the greatest disadvantages of IA. We aimed to investigate the risk factors for unsuccessful results following IA for IHPS.Medical records of patients with IHPS who were admitted to our institution between 2002 and 2016 and were initially administered atropine sulfate were retrospectively reviewed. Atropine was given intravenously (0.1 mg/kg/day in 8 divided doses). Oral feeding of milk was started with a small amount and increased in a stepwise fashion to full feed. IA therapy was judged unsuccessful from the presence of projectile vomiting more than three times a day or intolerance to a predetermined amount of milk.Among the 48 patients with IHPS, 33 patients were successfully treated with IA therapy and 15 patients needed surgical intervention. Univariate analyses showed that the risk factors for unsuccessful IA therapy were younger age, lower body weight, and shorter duration of symptoms before diagnosis. Multivariate analysis showed that an age at diagnosis of <30 days was the only significant risk factor for unsuccessful IA therapy (odds ratio 5.7, p = 0.03).An age at diagnosis <30 days was shown to be a risk factor for unsuccessful IA therapy in IHPS. This might be considered when IA therapy is applied to neonates with IHPS.