Pyloric Stenosis

Study guide:

Listen to the study guide -
00:00 / 00:00

Definition:​

  • Congenital hypertrophy of the pyloric muscles at the end of the stomach causing gastric outlet obstruction.
     

Epidemiology:

  • 2-4 per 1000 live births in the US.

  • Incidence is 1.4 cases per 10,000 live births according to a study done from

  • ​1990-2008 by Riyadh Military Hospital.

  • More common in males with M: F ratio of (5:1).


Etiology:

  • Most common cause is idiopathic.

  • Other causes:

Pyloric stenosis is the disease of firsts (1st):

  • In 1st born child (30%).

  • Presents in the 1st month.

  • Vomiting is the 1st event to happen after feeding.

  • 1st thing in management is correcting the electrolyte disturbance. 

Environmental​:

  •  Maternal smoking

  •  Bottle feeding

  •  Formula milk

Genetic​:

  • 200-fold higher rate among monozygotic twins and a 20-fold increase among dizygotic twins or siblings.

  • Associated with Turner and Edwards syndromes.

Others:

Macrolide antibiotic use (erythromycin, and clarithromycin) during the first two weeks of age.

Clinical Presentation: 

  • The hallmark characteristic is non-bilious projectile vomiting:

    • Dehydration, and weight loss.

  • Usually present during the first month (3-6 weeks of age):

    • But can present late up to 6 month of age.

  • Because of vomiting:

    • They usually have hypochloremic, hypokalemic metabolic alkalosis.

  • During physical exam:

    • Succussion splash during Auscultation.

    • Olive sign on palpation of the epigastric area.

    • Visible gastric peristaltic waves in the left lower quadrant. 

 

Diagnosis:

  • Blood laboratory electrolytes show ↓K+, ↓Cl- with metabolic alklasosis 

  • Best initial test is abdominal ultrasound:

    • Thickening of the pyloric sphincter

  • Most accurate diagnostic test is upper GI barium series showing:

Sign

String sign

Picture

Figure 1: Thin column of barium leaking.

Sign

Mushroom (Umbrella)  sign 

Picture

Figure 3: Impression made by the hypertrophic pylorus against the duodenum.

Sign

Shoulder sign

Picture

Figure 2: Filling defect in the antrum due to inward displacement of the muscle.

Sign

Railroad track sign 

Picture

Figure 4:Excess mucosa will lead to formation of two barium columns. 

Management:

  • Stabilize the patient and assess rehydration (half NS with 5%D and KCl):

    • Assess the benefit of immediate fluid restriction.

    • Electrolyte replacement.

  • NGT to decompress the bowel.

  • Surgical pyloromytotomy is the definitive treatment:

    • Oral feeding should be restarted after 12-24 hours post surgery. 

References:

  • Le, Tao, and Kendall Krause. First Aid For The Basic Sciences. New York: McGraw-Hill Medical, 2012. Print.

  • Lissauer, Tom, Graham Clayden, and Alan Craft. Illustrated Textbook Of Paediatrics. Edinburgh: Mosby, 2012. Print.

  • Cvetnic, William G, Eduardo Pino, and Christine E Koerner. USMLE Step 2 CK Pediatrics. [New York]: Kaplan, 2011. Print.

  • Fischer, Conrad. Master The Boards. Print.

  • Uptodate.com,. 'Infantile Hypertrophic Pyloric Stenosis'. N.p., 2015. Web. 15 Nov. 2015.

  • al-Salem AH, et al. 'Infantile Hypertrophic Pyloric Stenosis And Congenital Diaphragmatic Hernia. - Pubmed - NCBI'. Ncbi.nlm.nih.gov. N.p., 2015. Web. 15 Nov. 2015.

  • Kliegman, Robert. Nelson Textbook Of Pediatrics. Print.

  • Med.cmu.ac.th,. 'Infants With Vomitting'. N.p., 2015. Web. 15 Nov. 2015. (Figure 1).

  • Tdo.sagepub.com,. 'Sign In'. N.p., 2015. Web. 15 Nov. 2015. (Figure 2).

  • Med-ed.virginia.edu,. 'Pediatric Radiology'. N.p., 2015. Web. 15 Nov. 2015. (Figure 3).

  • Learningradiology.com,. 'Learningradiology-Hypertrophic, Pyloric Stenosis'. N.p., 2015. Web. 15 Nov. 2015. (Figure 4).

  • Shah, Samir S, Jeanine C Ronan, and Brian Alverson. Step-Up To Pediatrics. Print.

  • Kaplan Step 1 video, Pathology, 2015. 

 

 

Written by:         Roaa Amer


Reviewed by:      Adel Yasky
                             Lama Al Luhidan

Web publisher:  Adel Yasky

                            Bayan Alzomaili

Audio recording:

 

Read by: Bayan Alzomaili


Directed by: Rana Alzahrani


Audio production: Bayan Alzomaili