• Infantile pyloric stenosis is a relatively common condition that causes
severe projectile non-bilious vomiting in the first few weeks of life.
• It results from hypertrophy of the muscles surrounding the pylorus
leading to its narrowing and gastric outlet obstruction.
3. Epidemiology and Etiology
• Infantile pyloric stenosis occurs in the first 2–8 weeks of life.(Peak
incidence 3-5 weeks)
• Infantile pyloric stenosis has also been reported in the first few days
of life and in utero.
• No definitive causative factors have been identified.
• Both genetic and environmental factors seem to play a role in the
4. Genetic Predisposition
• Among races, more common in Caucasians
• Male preponderance,
• An increased risk to first-born infants (4 times)
• Positive family history
• Certain ABO blood types. (B and O)
5. Environmental factors
• Environmental factors associated with IHPS include the
• Method of feeding (breast-feeding versus formula feeding)
• Seasonal variability
• Erythromycin exposure
• Transpyloric feeding of premature infants.
6. Growth Factors and GIT Peptides
• Nitric oxide is an essential chemical transmitter responsible for
relaxation of the pyloric sphincter muscles.
• Deficiency in nitric oxide synthase in the myenteric plexus
• Hypertrophied circular muscle did not demonstrate any NO synthase
activity, but the activity in the longitudinal muscle was normal.
7. Growth Factors and GIT Peptides
• Substance P, a neurotransmitter responsible for enteric muscle
contraction, could produce pylorospasm leading to muscle
• This peptide is present in higher concentration in the pyloric muscle
of patients with IHPS.
8. Growth Factors and GIT Peptides
• Neurotrophins, which are important for nerve differentiation and
survival, have been noted to be decreased in IHPS.
• Specific receptors for these neurotrophins, the tyrosine kinase A
receptor c-kit, is not present in IHPS tissue.
• There is hypertrophy and hyperplasia of the two (circular and
longitudinal) muscular layers of the pylorus.
• This leads to narrowing of the pyloric canal and gastric outlet
• The pyloric canal becomes lengthened, and the whole pylorus
• The mucosa is usually edematous and thickened.
• Immunohistochemical analysis of the hypertrophic muscle reveals an
increase in fibroblasts, fibronectin, desmin, elastin and collagen.
11. Clinical Presentation
• Persistent, non-bilious projectile vomiting.
• Blood in the emesis that gives it a brownish discoloration or a coffee-
• Infants with IHPS remain hungry after emesis and are otherwise not ill
appearing or febrile
• A significant delay in diagnosis leading to severe dehydration,
however, results in a lethargic infant.
• Indirect hyperbilirubinemia may be seen in 1–2 % of affected infants.
13. Differential Diagnosis of Non bilious Vomiting
• Increased intracranial pressure
• Metabolic disorders.
• Antral webs
• Pyloric atresia
• Duplication cyst of the
• Ectopic pancreatic tissue within
the pyloric muscle
• Visible peristaltic waves in the left upper part of the abdomen
• Seventy-five percent have a palpable pyloric mass (olive sign) which is
felt in the right upper abdomen
• While examination
• Infant must be calm, warm, and cooperative
• Use of a pacifier or a small feeding (5% dextrose in water) may be helpful.
• If the stomach is distended, aspiration with a nasogastric tube
• The examiner should be willing to commit 5 to 15 minutes of uninterrupted
• One should be able to roll the hypertrophied pylorus under the fingertips to
be convinced of the diagnosis.
16. Abdominal X Ray
• Abdominal radiographs are not
• May show a fluid-filled or air-
• A markedly dilated stomach with
exaggerated incisura (caterpillar
sign) may be seen
17. Abdominal USG
• Most common initial imaging technique for the diagnosis
• Gold standard for diagnosing IHPS.
• Dependent on the level of experience and expertise of the
• The generally accepted criteria for a positive US study are a
• Pyloric muscle thickness of 3.5 (in premature infants) to 4 mm or more
• Pyloric channel length of 16 mm or greater
19. UGI Contrast Study
• Barium is generally preferred compared with water-soluble contrast
to avoid the chemical pneumonitis
• It shows narrowed pyloric canal filled with a thin stream of contrast
material, a “string sign” or the “railroad track sign”
• Residual barium from the stomach should be aspitated
• If barium does not leave the stomach, it is not possible to confirm the
diagnosis of IHPS because pylorospasm can also produce transient
complete gastric outlet obstruction.
21. Preoperative Preparation
• Prepare the infant adequately for anesthesia and surgical correction
• The length of preparation depends on the severity of the fluid and
• Three levels of severity primarily on the basis of the serum carbon
• Slight, <25 mEq/L;
• moderate, 26 to 35 mEq/L
• severe, >35 mEq/L
22. Preoperative Preparation
• Oral feedings should be discontinued.
• A nasogastric tube should not be placed routinely because it removes
additional fluid and hydrochloric acid from the stomach.
• Most infants with IHPS should be able to be resuscitated within a 24-
• Aggressive resuscitation should be avoided because it can produce
rapid fluid and electrolyte shifts, possible leading to seizures
• 5% dextrose in 0.45 normal saline containing 20 mEq/L of potassium
chloride is the optimal resuscitation fluid
23. Preoperative Preparation
• An initial rate for fluid resuscitation is 1.25 to 2 times the normal
maintenance rate until adequate fluid resuscitation and urine output
• Serum bicarbonate level should be below 30 mEq/L to avoid
respiratory depression and prolonged postoperative intubation
• Hyperbilirubinemia invariably resolves postoperatively.
24. Operative Procedure
• The operative procedure of choice remains the Ramstedt
• Minimal Laparotomy (“Open”) Technique
• Laparoscopic Procedure
25. Minimal Laparotomy (“Open”) Technique
• Two incisions (supra umbilical transverse and supra umbilical curved
• The pylorus can be stabilized by the index finger of the operating
surgeon standing to the right of the patient.
• The serosa on the anterior wall of the hypertrophied pylorus is incised
just proximal to the hypertrophied muscle extending just proximal to
the pyloric vein
• Bluntly splitting the hypertrophied muscle down to the submucosa
• Leave a few pyloric muscle fibers intact at the duodenal end to reduce
the risk for duodenal perforation
28. • Before closure, check for a leak from the stomach or duodenum
• If leak occurs, the submucosa should be approximated absorbable
suture and a portion of omentum placed over this site.
• Alternative technique is to
• reapproximate the myotomy site,
• rotate the pylorus 180 degrees,
• perform a myotomy on the posterior wall of the pylorus.
31. Comparison Of The Open Versus
• Faster recovery time
• Quicker return to full feeding
• Earlier postoperative discharge
• Decrease in postoperative
• Decrease in pain
• Greater complication rate
• missed perforation
• incomplete myotomy
• increase in operative time
• increased expense
32. Non Operative Management
• Intravenous and oral atropine has been used to treat pyloric stenosis
• It requires
• Prolonged hospitalization
• Skilled nursing
• Careful follow-up during treatment
33. Postoperative Management
• Feeding can be started within 4 hours after the surgical procedure.
• 80 % of patients continue to regurgitate after surgery
• Patients who continue to vomit 5 days after surgery may warrant
further radiologic investigation.