Pyloric stenosis

A condition affecting the gastrointestinal tract in infants

Pyloric stenosis is a condition that affects the gastrointestinal tract in infants, characterized by the narrowing of the pylorus, the opening from the stomach into the small intestine. This condition leads to severe projectile vomiting, dehydration, and weight loss in affected infants.

Pathophysiology

The pylorus is a muscular valve that regulates the passage of food from the stomach to the duodenum. In pyloric stenosis, the muscles of the pylorus become hypertrophied, leading to a narrowing of the pyloric channel. This hypertrophy obstructs gastric emptying, causing the stomach contents to be forcefully expelled.

Epidemiology

Pyloric stenosis is more common in males than females, with a male-to-female ratio of approximately 4:1. It typically presents in infants between 2 to 8 weeks of age. The condition is more prevalent in first-born children and has a higher incidence in Caucasian populations.

Clinical Presentation

Infants with pyloric stenosis often present with:

• Projectile vomiting: Non-bilious vomiting that occurs shortly after feeding.
• Dehydration: Due to loss of fluids from vomiting.
• Weight loss: Resulting from inadequate nutrition and fluid intake.
• Palpable "olive": A firm, mobile mass in the right upper quadrant of the abdomen, representing the hypertrophied pylorus.

Diagnosis

The diagnosis of pyloric stenosis is primarily clinical, supported by imaging studies.

Ultrasound

Ultrasound is the preferred imaging modality, revealing a thickened pyloric muscle and elongated pyloric channel. The "target sign" or "doughnut sign" is often described on transverse imaging.

Barium Swallow

A barium swallow study may show a "string sign," indicating a narrowed pyloric channel.

Management

The definitive treatment for pyloric stenosis is surgical intervention.

Pyloromyotomy

The standard surgical procedure is a pyloromyotomy, where the outer layer of the pylorus muscle is split, allowing the inner mucosa to bulge out and relieve the obstruction. This procedure can be performed via an open or laparoscopic approach.

Preoperative Care

Before surgery, it is crucial to correct dehydration and electrolyte imbalances. Intravenous fluids are administered to stabilize the infant.

Prognosis

With appropriate surgical treatment, the prognosis for infants with pyloric stenosis is excellent. Most infants recover fully and have no long-term complications.

Related pages

• Gastrointestinal tract
• Infant vomiting
• Hypertrophy
• Surgical procedures

Pyloric stenosis

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  Gray's Anatomy illustration of the stomach
• Local view of pyloric stenosis
  Local view of pyloric stenosis
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  Pyloromyotomy procedure
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  Horizontal view of pyloric stenosis
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  Pylorus stenosis
• Laparoscopic pyloromyotomy scar, 6 hours post-op
  Laparoscopic pyloromyotomy scar, 6 hours post-op