Pediatric Pyloric Stenosis

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Background

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.[1]

Pathophysiology

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.[2] 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.

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.

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.[3]

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.[4]

Epidemiology

Frequency

United States

The incidence of infantile hypertrophic pyloric stenosis is 2-4 per 1000 live births.

Mortality/Morbidity

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.

Race

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.

Sex

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.

Age

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.

History

Physical

Causes

Laboratory Studies

Imaging Studies

Procedures

Prehospital Care

Emergency Department Care

Consultations

Medication Summary

Further Inpatient Care

The infant with pyloric stenosis should continue to receive intravenous fluid until feeding is resumed. Feeding can be initiated 4-8 hours after recovery from anesthesia, although earlier feeding has been studied. Infants who are fed earlier than 4 hours do not have a worse total clinical outcome; however, they do vomit more frequently and more severely, leading to significant discomfort for the patient and anxiety for the parents.

Prognosis

Author

Jagvir Singh, MD, Director, Division of Pediatric Emergency Medicine, Lutheran General Hospital of Park Ridge

Disclosure: Nothing to disclose.

Coauthor(s)

Dara A Kass, MD, Clinical Assistant Instructor, Department of Emergency Medicine, State University of New York Downstate Medical Center, Kings County Hospital

Disclosure: Nothing to disclose.

Richard H Sinert, DO, Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, Research Director, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center

Disclosure: Nothing to disclose.

Specialty Editors

Garry Wilkes, MBBS, FACEM, Director of Emergency Medicine, Calvary Hospital, Canberra, ACT; Adjunct Associate Professor, Edith Cowan University, Western Australia

Disclosure: Nothing to disclose.

Mary L Windle, PharmD, Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Grace M Young, MD, Associate Professor, Department of Pediatrics, University of Maryland Medical Center

Disclosure: Nothing to disclose.

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

Disclosure: Nothing to disclose.

Chief Editor

Richard G Bachur, MD, Associate Professor of Pediatrics, Harvard Medical School; Associate Chief and Fellowship Director, Attending Physician, Division of Emergency Medicine, Children's Hospital of Boston

Disclosure: Nothing to disclose.

References

  1. Pandya S, Heiss K. Pyloric stenosis in pediatric surgery: an evidence-based review. Surg Clin North Am. Jun 2012;92(3):527-39, vii-viii. [View Abstract]
  2. Panteli C. New insights into the pathogenesis of infantile pyloric stenosis. Pediatr Surg Int. Sep 16 2009;[View Abstract]
  3. Rogers IM. The true cause of pyloric stenosis is hyperacidity. Acta Paediatr. Feb 2006;95(2):132-6. [View Abstract]
  4. Krogh C, Fischer TK, Skotte L, Biggar RJ, Oyen N, Skytthe A. Familial aggregation and heritability of pyloric stenosis. JAMA. Jun 16 2010;303(23):2393-9. [View Abstract]
  5. [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.
  6. Maheshwari P, Abograra A, Shamam O. Sonographic evaluation of gastrointestinal obstruction in infants: a pictorial essay. J Pediatr Surg. Oct 2009;44(10):2037-42. [View Abstract]
  7. 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. Jul 2012;21(3):430-4. [View Abstract]
  8. 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. Feb 2007;17(1):131-6. [View Abstract]
  9. 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. Apr 2007;42(4):692-8. [View Abstract]
  10. 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. Jun 2007;166(6):553-7. [View Abstract]
  11. 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. May 2007;42(5):865-8. [View Abstract]
  12. 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. Apr 2007;17(2):235-7. [View Abstract]
  13. Kelley-Quon LI, Tseng CH, Jen HC, Shew SB. Hospital type predicts surgical complications for infants with hypertrophic pyloric stenosis. Am Surg. Oct 2012;78(10):1079-82. [View Abstract]
  14. 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. May 2004;23(5):641-6. [View Abstract]
  15. Garcia VF, Randolph JG. Pyloric stenosis: diagnosis and management. Pediatr Rev. Apr 1990;11(10):292-6. [View Abstract]
  16. Godbole P, Sprigg A, Dickson JA. Ultrasound compared with clinical examination in infantile hypertrophic pyloric stenosis. Arch Dis Child. Oct 1996;75(4):335-7. [View Abstract]
  17. Hernanz-Schulman M. Infantile hypertrophic pyloric stenosis. Radiology. May 2003;227(2):319-31. [View Abstract]
  18. Hernanz-Schulman M, Sells LL, Ambrosino MM. Hypertrophic pyloric stenosis in the infant without a palpable olive: accuracy of sonographic diagnosis. Radiology. Dec 1994;193(3):771-6. [View Abstract]
  19. Huang YC, Su BH. Medical treatment with atropine sulfate for hypertrophic pyloric stenosis. Acta Paediatr Taiwan. May-Jun 2004;45(3):136-40. [View Abstract]
  20. Irish MS, Pearl RH, Caty MG, Glick PL. The approach to common abdominal diagnosis in infants and children. Pediatr Clin North Am. Aug 1998;45(4):729-72. [View Abstract]
  21. Kim SS, Lau ST, Lee SL. Pyloromyotomy: a comparison of laparoscopic, circumumbilical, and right upper quadrant operative techniques. J Am Coll Surg. Jul 2005;201(1):66-70. [View Abstract]
  22. Liacouras CA, Cook-Sather SD, Schreiner MS, Bellah RD. Endoscopic findings in hypertrophic pyloric stenosis: appearance in classic and evolving disease. Gastrointest Endosc. May 1997;45(5):371-4. [View Abstract]
  23. 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. Aug 1996;23(2):172-7. [View Abstract]
  24. Schechter R, Torfs CP, Bateson TF. The epidemiology of infantile hypertrophic pyloric stenosis. Paediatr Perinat Epidemiol. Oct 1997;11(4):407-27. [View Abstract]
  25. 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. [View Abstract]
  26. Spinelli C, Bertocchini A, Massimetti M. Muscle thickness in infants hypertrophic pyloric stenosis. Pediatr Med Chir. Mar-Apr 2003;25(2):148-50. [View Abstract]
  27. Sretenovic A, Smoljanic Z, Korac G. [Conservative treatment of hypertrophic pyloric stenosis in children]. Srp Arh Celok Lek. Oct 2004;132 Suppl 1:93-6. [View Abstract]
  28. Takahashi T. Pathophysiological significance of neuronal nitric oxide synthase in the gastrointestinal tract. J Gastroenterol. 2003;38(5):421-30. [View Abstract]
  29. van der Bilt JD, Kramer WL, van der Zee DC. Early feeding after laparoscopic pyloromyotomy: the pros and cons. Surg Endosc. May 2004;18(5):746-8. [View Abstract]
  30. Vasavada P. Ultrasound evaluation of acute abdominal emergencies in infants and children. Radiol Clin North Am. Mar 2004;42(2):445-56. [View Abstract]

Lateral view from an upper GI study demonstrates the double-track sign.

Lateral view from an upper GI study demonstrates the double-track sign.