HYPERTROPHIC PYLORIC STENOSIS

PYLORIC ATRESIA

 

Pyloric atresia is a rare congenital anomaly representing only 1% of gastrointestinal atresias (1).
 

PATHYPHYSIOLOGICAL CLASSIFICATION (1)
  1. Antral gap atresia.
  2. Pyloric gap atresia (types I-III).
  3. Pyloric septum (solid atresia).
  4. Pyloric membrane (types I-II).
  5. Antral membrane (web and "windsock" types).

 

ULTRASOUND (2)
  • Dilated esophagus.
  • Dilated stomach (± a thick wall) (3).
  • Marked gastric peristalsis (due to impairment of gastric filling and emptying).
  • Polyhydramnios.
  • Color Doppler has been used to detect biphasic flow during breathing movement suggesting gastroesophageal reflux (2).
  • The lower intestines in pyloric atresia appear normal because of the passage of bile (3).

 

Hypertrophic pyloric stenosis

 

 

 

Dilatation of the stomach. This is indistinguishable from pyloric atresia on antenatal scan.

Pyloric Atresia


 

ASSOCIATED ANOMALIES
  • Association with other anomalies are frequent, especially epidermolysis bullosa (occurs in 14% - 28% of cases) (2,4,5).
  • Gastrointestinal (duodenal stenosis, malrotation).
  • Cardiovascular (coarctation of the aorta, VSD, Patent ductus arteriosis).
  • Hypospadius.
  • Dysmorphic facial features and laryngomalacia.
  • Epidermolysis Bullosa (6,7).  Junctional Epidermolysis Bullosa (JEB) is a group of inherited mechanobullous diseases having an autosomal recessive mode of inheritance, and characterized by  blister formation of the lamina lucida of the epidermal basement layer, and hypoplastic hemidesmosomes. EB-PA is a sub-type  of JEB, associated with congenital pyloric atresia. It is known to be caused by the ITGA6 or ITGB4 genes encoding for the integrin alpha 6 or beta 4 subunit respectively  (8,9).

 

REFERENCES
  1. Moore CCM. Congenital gastric outlet obstruction. J Pediatr Surg 1989;24:1241-1246.
  2. Rizzo G, Capponi A, Arduini D et.al. Prenatal diagnosis of gastroesophageal reflux by color and pulsed Doppler ultrasonography in a case of congenital pyloric atresia. Ultrasound Obstet Gynecol 1995;6:290-292.
  3. Hasegawa T, Kubota A, Imura K et.al. Prenatal diagnosis of congenital pyloric atresia. J Clin Ultrasound 1993;21:278-281.
  4. Sharony R, Sinow R, Asch M et.al. Prenatal ultrasound diagnosis of gastric outlet obstruction due to a pyloric web. Prenat Diagn 1995;15:56-59.
  5. Bell MJ, Ternberg JL, Keating JP et.al. Prepyloric gastric antral web: a puzzling epidemic. J Pediatr Surg 1978;13:307-313.
  6. De Jenlis B De, Deruelle P, Kacet N . et.al. Prenatal findings in epidermolysis bullosa with pyloric atresia in a family not known to be at risk. Ultrasound Obstet Gynecol 2005;25:607-609.
  7. Ruzzi L, Gagnoux-Palacois L, Pinola M et.al. A homozygous mutation in the integrin alpha 6 gene in junctional epidermolysis bullosa with pyloric atresia. J Clin Invest 1997;99:2826-2831.
  8. Vidal F, Aberdam D, Miquel C et.al. Integrin beta 4 mutations associated with junctional epidermolysis bullosa with pyloric atresia..Nat Genet 1995;10:229-234.