Pyloric stenosis

Learning objectives

Describe the electrolyte and acid-base abnormalities associated with pyloric stenosis
Explain why these electrolyte and acid-base abnormalities need to be corrected preoperatively
Anesthetic management of a pediatric patient with pyloric stenosis

Pyloric stenosis, or infantile hypertrophic pyloric stenosis, is an uncommon condition in infants characterized by abnormal thickening of the pylorus muscles in the stomach, leading to gastric outlet obstruction
Typically seen between 2 and 12 weeks of age, patients present with projectile vomiting after feedings, dehydration, and failure to thrive
The danger of pyloric stenosis comes from the dehydration and electrolyte disturbance rather than the underlying problem itself → infant has to be stabilized by correcting the dehydration and hypochloremic alkalosis with IV fluids

Symptoms usually appear within 3-5 weeks after birth
Bile-free projectile vomiting after every feeding
Persistent hunger
Stomach contractions (visible peristalsis in the left upper quadrant from left to right)
Changes in bowel movements
Weight problems

Correction of dehydration and hypochloremic alkalosis before surgery with IV fluids → accomplished within 24-48 hours
Surgery: Pyloromyotomy

Vomiting associated with pyloric stenosis results in hypochloremia, hyponatremia, hypokalemia, metabolic alkalosis, and dehydration, all of which have to be corrected before general anesthesia and surgery
Empty the stomach using a nasogastric or orogastric tube before induction of anesthesia
Ensure an adequate depth of anesthesia with a complete neuromuscular block before laryngoscopy to minimize the risk of regurgitation and pulmonary aspiration