尽管该病较为常见,但病因仍不明。不支持强遗传倾向。[20]MacMahon B. The continuing enigma of pyloric stenosis of infancy: a review. Epidemiology. 2006;17:195-201.http://www.ncbi.nlm.nih.gov/pubmed/16477261?tool=bestpractice.com进食后胃窦胀和重复性收缩导致的幽门肥厚导致胃酸过多被认为是病因之一。[21]Rogers IM. The true cause of pyloric stenosis is hyperacidity. Acta Paediatr. 2006;95:132-136.http://www.ncbi.nlm.nih.gov/pubmed/16449017?tool=bestpractice.com此外,幽门肌肉神经元支配不良也有所影响。[22]Vanderwinden JM, Liu H, Menu R, et al. The pathology of infantile hypertrophic pyloric stenosis after healing. J Pediatr Surg. 1996;31:1530-1534.http://www.ncbi.nlm.nih.gov/pubmed/8943116?tool=bestpractice.com[23]Okazaki T, Yamataka A, Fujiwara T, et al. Abnormal distribution of nerve terminals in infantile hypertrophic pyloric stenosis. J Pediatr Surg. 1994;29:655-658.http://www.ncbi.nlm.nih.gov/pubmed/8035277?tool=bestpractice.com肠道起搏细胞 Cajal 的缺失推测为导致幽门狭窄的另一种病理机制。[24]Vanderwinden JM, Liu H, De Laet MH, et al. Study of the interstitial cells of Cajal in infantile hypertrophic pyloric stenosis. Gastroenterology. 1996;111:279-288.http://www.ncbi.nlm.nih.gov/pubmed/8690192?tool=bestpractice.com一氧化氮合成酶缺乏也是为生化病因,因其会减少平滑肌松弛。[25]Vanderwinden JM, Mailleux P, Schiffmann SN, et al. Nitric oxide synthase activity in infantile hypertrophic pyloric stenosis. N Engl J Med. 1992;327:511-515 (erratum in: N Engl J Med. 1992;327:1252).http://www.ncbi.nlm.nih.gov/pubmed/1378938?tool=bestpractice.com[26]Subramaniam R, Doig CM, Moore L. Nitric oxide synthase is absent in only a subset of cases of pyloric stenosis. J Pediatr Surg. 2001;36:616-619.http://www.ncbi.nlm.nih.gov/pubmed/11283889?tool=bestpractice.com[27]Kusafuka T, Puri P. Altered messenger RNA expression of the neuronal nitric oxide synthase gene in infantile hypertrophic pyloric stenosis. Pediatr Surg Int. 1997;12:576-579.http://www.ncbi.nlm.nih.gov/pubmed/9354728?tool=bestpractice.com先前的报告也表明,接触口服红霉素与幽门狭窄显著相关。[28]SanFilippo A. Infantile hypertrophic pyloric stenosis related to ingestion of erythromycine estolate: a report of five cases. J Pediatr Surg. 1976;11:177-180.http://www.ncbi.nlm.nih.gov/pubmed/1263054?tool=bestpractice.com[29]Honein MA, Paulozzi LJ, Himelright IM, et al. Infantile hypertrophic pyloric stenosis after pertussis prophylaxis with erythromycin: a case review and cohort study. Lancet. 1999;354:2101-2105 (erratum in: Lancet. 2000;355:758).http://www.ncbi.nlm.nih.gov/pubmed/10609814?tool=bestpractice.com[30]Cooper WO, Griffin MR, Arbogast P, et al. Very early exposure to erythromycin and infantile hypertrophic pyloric stenosis. Arch Pediatr Adolesc Med. 2002;156:647-650.http://archpedi.ama-assn.org/cgi/content/full/156/7/647http://www.ncbi.nlm.nih.gov/pubmed/12090829?tool=bestpractice.com然而,这些理论都未被确认。