Sunday, January 28, 2007

Pyloric stenosis

Congenital hypertrophic pyloric stenosis

  • Seen in infants as a disorder that affects males three to four times more often than females, occurring in 1 in 300-900 live births.
  • Familial occurrence implicates a multifactorial pattern of inheritance; monozygotic twins have a high rate of concordance of the condition.
  • May occur in association with Turner syndrome, trisomy 18, and esophageal atresia.
  • The stenosis from hypertrophy, and possibly hyperplasia, of the muscularis propria of the pylorus. Edema and inflammatory changes in the mucosa and submucosa may aggravate the narrowing.
  • Regurgitation and persistent, projectile, nonbilious vomiting usually appear in the second or third week of life.
  • Physical examination reveals visible peristalsis and a firm, ovoid palpable mass in the region of the pylorus or distal stomach.
  • Investigations include barium swallow to look for narrowing, blood tests to check for electrolyte imbalances.
  • A pyloromyotomy - surgical muscle splitting - is curative.
  • After surgery, most babies are able to return to normal feedings quickly. The baby starts feeding again 3 to 4 hours after the surgery, and the baby can return to breast-feeding or the formula that he was on prior to the surgery. Because of swelling at the surgery site, the baby may still vomit small amounts for a day or so after surgery. As long as there are no complications, most babies who have undergone pyloromyotomy can return to a normal feeding schedule and be sent home within 48 hours of the surgery.

Acquired pyloric stenosis

  • Seen in adults.
  • One of the long-term risks of antral gastritis or peptic ulcers close to the pylorus.
  • Carcinomas of the pyloric region, lymphomas, or adjacent carcinomas of the pancreas are more ominous causes. In these cases, inflammatory fibrosis or malignant infiltration narrow the pyloric channel, producing pyloric outlet obstruction.
  • In rare instances, hypertrophic pyloric stenosis is the result of prolonged pyloric spasm.

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