Pediatric Pyloric Stenosis
- Author: Jagvir Singh, MD; Chief Editor: Kirsten A Bechtel, MD more...
Pyloric stenosis, also known as infantile hypertrophic pyloric stenosis (IHPS), is the most common cause of intestinal obstruction in infancy. IHPS occurs secondary to hypertrophy and hyperplasia of the muscular layers of the pylorus, causing a functional gastric outlet obstruction.
In 1717, Blair first reported autopsy findings of pyloric stenosis. Although the description of the signs and symptoms of infantile hypertrophic pyloric stenosis can be found in the 17th century, the clinical picture and pathology were not accurately described until 1887 by the Danish pediatrician, Hirschsprung. Prior to 1912, early successful surgical procedures included gastroenterostomy, pyloroplasty, and forcible dilatation via gastrostomy. In 1912, Ramstedt observed an uneventful recovery in a patient following pyloroplasty, where sutures used in reapproximating the seromuscular layer had disrupted. Following this observation, he began leaving the split muscle layer unsutured in all subsequent repairs. The Ramstedt pyloromyotomy remains the standard procedure for pyloric stenosis today.
According to Pandya and Heiss, current recommendations include ultrasonography for diagnosis, preoperative corrections of electrolytes, and use of minimally invasive treatment techniques.
Marked hypertrophy and hyperplasia of the 2 (circular and longitudinal) muscular layers of the pylorus occurs, leading to narrowing of the gastric antrum. The pyloric canal becomes lengthened, and the whole pylorus becomes thickened. The mucosa is usually edematous and thickened. In advanced cases, the stomach becomes markedly dilated in response to near-complete obstruction.
The causes of infantile hypertrophic pyloric stenosis are multifactorial. Both environmental factors and hereditary factors are believed to be contributory. Possible etiologic factors include deficiency of nitric oxide synthase containing neurons, abnormal myenteric plexus innervation, infantile hypergastrinemia, and exposure to macrolide antibiotics.
A 2013 study found that bottle-feeding may play a role in an increased risk of hypertrophic pyloric stenosis, and another 2014 cohort study assessed that treatment of young infants with macrolide antibiotics was strongly associated with infantile hypertrophic pyloric stenosis (IHPS) and should therefore only be administered if potential treatment benefits outweigh the risk. Maternal use of macrolides during the first 2 weeks after birth was also associated with an increased risk of IHPS.
A study evaluated the association between exposure to oral azithromycin and erythromycin and subsequent development of infantile hypertrophic pyloric stenosis (IHPS). The study concluded that ingestion of oral azithromycin and erythromycin places young infants at increased risk of developing IHPS. The authors further reported that this association is strongest if the exposure occurred in the first 2 weeks of life, although persists to a lesser degree in children between 2 and 6 weeks of age.[5, 6]
Nitric oxide has been demonstrated as a major inhibitory nonadrenergic, noncholinergic neurotransmitter in the GI tract, causing relaxation of smooth muscle of the myenteric plexus upon its release. Impairment of this neuronal nitric oxide synthase (nNOS) synthesis has been implicated in infantile hypertrophic pyloric stenosis, in addition to achalasia, diabetic gastroparesis, and Hirschsprung disease.
A 2013 study reported the possibility that low serum lipids could be a risk factor for IHPS. Further studies are needed to determine the significance of these findings.
Rogers has suggested, that persisting duodenal hyperacidity, secondary due to a high parietal cell mass (PCM) and loss of gastrin control, produces pyloric stenosis from repeated pyloric contraction in response to hyperacidity.
No specific pattern of inheritance exists. It is more common in first-born white males of northern European ancestry and more concordant in monozygotic than dizygotic twins. It also has predominance in children of affected parents (as many as 7%).
A nationwide study of nearly 2 million Danish children born between 1977 and 2008 shows strong evidence for familial aggregation and heritability of pyloric stenosis. Results of the study found a heritability rate of 87% in affected families, lending to the idea that familial aggregation may be explained by shared genes that affect responses to postnatal factors in causing pyloric stenosis.
The incidence of infantile hypertrophic pyloric stenosis is 2-4 per 1000 live births.
Death from infantile hypertrophic pyloric stenosis is rare and unexpected. The reported mortality rate is very low and usually results from delays in diagnosis with eventual dehydration and shock.
Infantile hypertrophic pyloric stenosis is more common in whites than Hispanics, blacks, or Asians. The incidence is 2.4 per 1000 live births in whites, 1.8 in Hispanics, 0.7 in blacks, and 0.6 in Asians. It is also less common amongst children of mixed race parents.
Infantile hypertrophic pyloric stenosis has a male-to-female predominance of 4:1, with 30% of patients with infantile hypertrophic pyloric stenosis being first-born males.
The usual age of presentation is approximately 3 weeks of life (1-18 wk). Approximately 95% of infantile hypertrophic pyloric stenosis cases are diagnosed in those aged 3-12 weeks. Infantile hypertrophic pyloric stenosis is rare in premature infants. In addition, premature infants have a delayed diagnosis secondary to low birth weight and atypical presentation.
Pandya S, Heiss K. Pyloric stenosis in pediatric surgery: an evidence-based review. Surg Clin North Am. 2012 Jun. 92(3):527-39, vii-viii. [Medline].
Panteli C. New insights into the pathogenesis of infantile pyloric stenosis. Pediatr Surg Int. 2009 Sep 16. [Medline].
McAteer JP, Ledbetter DJ, Goldin AB. Role of bottle feeding in the etiology of hypertrophic pyloric stenosis. JAMA Pediatr. 2013 Dec. 167(12):1143-9. [Medline].
Lund M, Pasternak B, Davidsen RB, Feenstra B, Krogh C, Diaz LJ, et al. Use of macrolides in mother and child and risk of infantile hypertrophic pyloric stenosis: nationwide cohort study. BMJ. 2014 Mar 11. 348:g1908. [Medline]. [Full Text].
Eberly MD, Eide MB, Thompson JL, Nylund CM. Azithromycin in early infancy and pyloric stenosis. Pediatrics. 2015 Mar. 135 (3):483-8. [Medline].
Barclay L. Azithromycin Linked to Pyloric Stenosis Risk in Young Infants. Medscape Medical News. Available at http://www.medscape.com/viewarticle/839845. February 16, 2015; Accessed: July 28, 2015.
Feenstra B, Geller F, Carstensen L, Romitti PA, Körberg IB, Bedell B, et al. Plasma lipids, genetic variants near APOA1, and the risk of infantile hypertrophic pyloric stenosis. JAMA. 2013 Aug 21. 310(7):714-21. [Medline]. [Full Text].
Rogers IM. The true cause of pyloric stenosis is hyperacidity. Acta Paediatr. 2006 Feb. 95(2):132-6. [Medline].
Krogh C, Fischer TK, Skotte L, Biggar RJ, Oyen N, Skytthe A. Familial aggregation and heritability of pyloric stenosis. JAMA. 2010 Jun 16. 303(23):2393-9. [Medline].
[Guideline] Cincinnati Children's Hospital Medical Center. Evidence based clinical practice guideline for hypertrophic pyloric stenosis. Cincinnati (OH): Cincinnati Children's Hospital Medical Center; 2007 Nov 14. [Full Text].
Maheshwari P, Abograra A, Shamam O. Sonographic evaluation of gastrointestinal obstruction in infants: a pictorial essay. J Pediatr Surg. 2009 Oct. 44(10):2037-42. [Medline].
Saha N, Saha DK, Rahman MA, Aziz MA, Islam MK. Laparoscopic versus Open Pyloromyotomy for Infantile Hypertropic Pyloric Stenosis: An Early Experience. Mymensingh Med J. 2012 Jul. 21(3):430-4. [Medline].
Aldridge RD, MacKinlay GA, Aldridge RB. Choice of incision: the experience and evolution of surgical management of infantile hypertrophic pyloric stenosis. J Laparoendosc Adv Surg Tech A. 2007 Feb. 17(1):131-6. [Medline].
Leclair MD, Plattner V, Mirallie E, Lejus C, Nguyen JM, Podevin G. Laparoscopic pyloromyotomy for hypertrophic pyloric stenosis: a prospective, randomized controlled trial. J Pediatr Surg. 2007 Apr. 42(4):692-8. [Medline].
van den Ende ED, Allema JH, Hazebroek FW, Breslau PJ. Can pyloromyotomy for infantile hypertrophic pyloric stenosis be performed in any hospital? Results from two teaching hospitals. Eur J Pediatr. 2007 Jun. 166(6):553-7. [Medline].
Taqi E, Boutros J, Emil S, Dube S, Puligandla P, Flageole H. Evaluation of surgical approaches to pyloromyotomy: a single-center experience. J Pediatr Surg. 2007 May. 42(5):865-8. [Medline].
Adibe OO, Nichol PF, Lim FY, Mattei P. Ad libitum feeds after laparoscopic pyloromyotomy: a retrospective comparison with a standardized feeding regimen in 227 infants. J Laparoendosc Adv Surg Tech A. 2007 Apr. 17(2):235-7. [Medline].
Kelley-Quon LI, Tseng CH, Jen HC, Shew SB. Hospital type predicts surgical complications for infants with hypertrophic pyloric stenosis. Am Surg. 2012 Oct. 78(10):1079-82. [Medline].
Cohen HL, Blumer SL, Zucconi WB. The sonographic double-track sign: not pathognomonic for hypertrophic pyloric stenosis; can be seen in pylorospasm. J Ultrasound Med. 2004 May. 23(5):641-6. [Medline].
Garcia VF, Randolph JG. Pyloric stenosis: diagnosis and management. Pediatr Rev. 1990 Apr. 11(10):292-6. [Medline].
Godbole P, Sprigg A, Dickson JA. Ultrasound compared with clinical examination in infantile hypertrophic pyloric stenosis. Arch Dis Child. 1996 Oct. 75(4):335-7. [Medline].
Hernanz-Schulman M. Infantile hypertrophic pyloric stenosis. Radiology. 2003 May. 227(2):319-31. [Medline].
Hernanz-Schulman M, Sells LL, Ambrosino MM. Hypertrophic pyloric stenosis in the infant without a palpable olive: accuracy of sonographic diagnosis. Radiology. 1994 Dec. 193(3):771-6. [Medline].
Huang YC, Su BH. Medical treatment with atropine sulfate for hypertrophic pyloric stenosis. Acta Paediatr Taiwan. 2004 May-Jun. 45(3):136-40. [Medline].
Irish MS, Pearl RH, Caty MG, Glick PL. The approach to common abdominal diagnosis in infants and children. Pediatr Clin North Am. 1998 Aug. 45(4):729-72. [Medline].
Kim SS, Lau ST, Lee SL. Pyloromyotomy: a comparison of laparoscopic, circumumbilical, and right upper quadrant operative techniques. J Am Coll Surg. 2005 Jul. 201(1):66-70. [Medline].
Liacouras CA, Cook-Sather SD, Schreiner MS, Bellah RD. Endoscopic findings in hypertrophic pyloric stenosis: appearance in classic and evolving disease. Gastrointest Endosc. 1997 May. 45(5):371-4. [Medline].
Nagita A, Yamaguchi J, Amemoto K, et al. Management and ultrasonographic appearance of infantile hypertrophic pyloric stenosis with intravenous atropine sulfate. J Pediatr Gastroenterol Nutr. 1996 Aug. 23(2):172-7. [Medline].
Schechter R, Torfs CP, Bateson TF. The epidemiology of infantile hypertrophic pyloric stenosis. Paediatr Perinat Epidemiol. 1997 Oct. 11(4):407-27. [Medline].
Sorensen HT, Skriver MV, Pedersen L. Risk of infantile hypertrophic pyloric stenosis after maternal postnatal use of macrolides. Scand J Infect Dis. 2003. 35(2):104-6. [Medline].
Spinelli C, Bertocchini A, Massimetti M. Muscle thickness in infants hypertrophic pyloric stenosis. Pediatr Med Chir. 2003 Mar-Apr. 25(2):148-50. [Medline].
Sretenovic A, Smoljanic Z, Korac G. [Conservative treatment of hypertrophic pyloric stenosis in children]. Srp Arh Celok Lek. 2004 Oct. 132 Suppl 1:93-6. [Medline].
Takahashi T. Pathophysiological significance of neuronal nitric oxide synthase in the gastrointestinal tract. J Gastroenterol. 2003. 38(5):421-30. [Medline].
van der Bilt JD, Kramer WL, van der Zee DC. Early feeding after laparoscopic pyloromyotomy: the pros and cons. Surg Endosc. 2004 May. 18(5):746-8. [Medline].
Vasavada P. Ultrasound evaluation of acute abdominal emergencies in infants and children. Radiol Clin North Am. 2004 Mar. 42(2):445-56. [Medline].