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

Definition and mechanisms

• 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

Signs and symptoms

• 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

Complications

• Failure to grow and develop, failure to thrive
• Dehydration, hypovolemia
• Metabolic alkalosis
• Electrolyte abnormalities (hypochloremia, hyponatremia, hypokalemia)
• Stomach irritation
• Jaundice

Risk factors

• First-born male children
• Preterm birth
• Cesarean section
• Family history
• Smoking during pregnancy
• Bottle feeding
• Early antibiotic use (e.g., erythromycin to treat whooping cough)
• White and Hispanic children

Pathophysiology

Treatment

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

Management

Keep in mind

• 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

Suggested reading

• Craig R, Deeley A. Anaesthesia for pyloromyotomy. BJA Educ. 2018;18(6):173-177.
• Pollard BJ, Kitchen G. Handbook of Clinical Anaesthesia. 4th ed. Taylor & Francis group; 2018. Chapter 24 Paediatrics, Lomas B.
• Houck PJ. PYLORIC STENOSIS. In: Houck PJ, Haché M, Sun LS. eds. Handbook of Pediatric Anesthesia. McGraw Hill; 2015. Accessed February 14, 2023. https://accessanesthesiology.mhmedical.com/content.aspx?bookid=1189&sectionid=70363285