Risk factors for unsuccessful atropine therapy in hypertrophic pyloric stenosis

I.v. 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 investigated the risk factors for unsuccessful results following IA for IHPS.

Medical records of patients with IHPS who were admitted to Kimitsu Chuo Hospital between 2002 and 2016 and were initially given atropine sulfate were retrospectively reviewed. Atropine was given i.v. (0.1 mg/kg/day in eight divided doses). Oral feeding of milk was started with a small amount and increased in a stepwise fashion to full feed. IA therapy was defined as unsuccessful in the presence of projectile vomiting more than three times a day or intolerance to a predetermined amount of milk.

Of the 48 patients with IHPS, 33 patients were successfully treated with IA and 15 patients needed surgical intervention. On univariate analysis the risk factors for unsuccessful IA therapy were younger age, lower bodyweight, and shorter duration of symptoms before diagnosis. On multivariate analysis age at diagnosis < 30 days was the only significant risk factor for unsuccessful IA therapy (OR, 5.7 l P = 0.03).

Age at diagnosis < 30 days is a risk factor for unsuccessful IA therapy in IHPS. This might be considered when IA therapy is used for neonates with IHPS.