Pyloric Stenosis

Pyloric Stenosis


  • Not congenital (symptoms are not present at birth)usually presents at 3 to 4 weeks of life
  • More common in boys (4:1)
  • Pylorus thickened, elongated and lumen narrowed due to hypertrophy of circular muscle
  • Increased incidence in 0 and B groups
  • Increased risk in Turner syndrome and Trisomy 18
  • Erythromycin or azithromycin exposure, in the first 2 weeks of life – increased incidence


  • The classical presentation is non-bilious, projectile vomiting between 2 – 8 weeks of age
  • Persistent vomiting & dehydration, malnutrition, hypokalemic, hypochloraemic alkalosis and paradoxical aciduria
  • Visible gastric peristaltic waves moving from left to right across the upper abdomen
  • In Congenital  hypertrophic  pyloric stenosis of infancy Baby is hungry soon after vomiting
  •  Abdominal lump,Constipation,Weight Loss is seen
  • Palpation of the pyloric tumor (olive-shaped) in the epigastrium or right upper quadrant is pathognomic
  • The classical electrolyte abnormality associated withpyloric stenosis is 
    • Hypokalemic, 
    • Hypochloremic metabolic alkalosis, presumably due to ongoing gastric acid loss from vomiting. 
    • Paradoxical acidurea is sometimes noted (with progressive Hypokalemia and hypovolemia) because the kidney excretes protons in exchange of sodium in an attempt to conserve fluid


  • X-ray after barium meal shows string sign or double neck sign and shoulder sign & Single bubble appearance
  • Diagnosis confirmed by USG>95% accuracy
  • Persistent pyloric muscle thickness more than 3 to 4 mm
  • Pyloric canal length more than 15 to 18 mm in the presence of functional gastric outlet obstruction
  • Pyloric thickness (serosa to serosa) of 15 mm or greater
  • Target sign on transverse images of the pylorus
  • Failure of the channel to open during a minimum of 15 minutes of scanning
  • Retrograde or hyperperistaltic contractions
  • Antral nipple sign (prolapse of redundant mucosa into the antrum, which creates a pseudomass)
  • Double-track sign(redundant mucosa in the narrowed lumen, which creates 2 mucosal outlines)


  • Fluid resuscitation and correction of electrolyte abnormalities and metabolic alkalosis is essential before surgery. 
  • Surgery done is Fredet-Ranzstedt pyloromyotomy. (In it the pyloric mass is split without cutting the mucosa)Ramstedt’s operation (pyloromyotomy) is the treatment of choice. The hypertrophied circular muscle fibres are cut longitudinally

Exam Important

  • Congenital  hypertrophic  pyloric stenosis of infancy most commonly occurs in first born male child
  • Congenital  hypertrophic  pyloric stenosis of infancy usually presents at 3 to 4 weeks of life
  • In Congenital  hypertrophic  pyloric stenosis of infancy Baby is hungry soon after vomiting
  • Hypokalemic,Hypochloremic metabolic alkalosis are the Metabolic abnormalities associated with Congenital Pyloric Stenosis 
  • A 3 week old patient presenting with vomiting and failure to thrive is found to have pyloric stenosis should be treated with correction of electrolyte disturbances
  • Drug which can cause Hypertrophic Pyloric stenosis is Erythromycin
  • The pyloric tumour is best felt during feeding is the most characteristic feature of congenital hypertrophic pyloric stenosis
  • Ultrasonography is the diagnostic test in hypertrophic pyloric stenosis
  • Clinical features of pyloric stenosis in infants are Abdominal lump,Constipation,Weight Loss &  Metabolic alkalosis
  • The vomiting in pyloric stenosis may or may not be projectile, however non bilious vomiting after feed is the characteristic feature.
  • Remsted’s operation is done for  pyloric stenosis
  • Patient with low serum calcium posted for pyrolic stenosis surgery should undergo Serum protein level investigation before administration calcium supplement
  • USG findings of congenital pyloric stenosis  shows > 95% accuracy,Segment length >16mm & Thickness >4mm
  • Single bubble appearance string sign or double neck sign and shoulder sign is seen in  X-ray finding of pyloric stenosis
  • In congenital pyloric stenosis the defect usually lies in Circular muscle fibres antrum
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