Pyloric stenosis - NYSORA

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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

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

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

pyloric stenosis, hypertrophy, hyperplasia, pyloric sphincter, pylorus, obstruction, constriction, peristalsis, vomiting, dilated stomach, dehydration, hypochloremic alkalosis

Treatment

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

Management

pyloric stenosis, preoperative, intraoperative, postoperative, management, normal saline, electrolyte, acid/base, nasogastric tube, orogastric tube, monitoring, aspiration risk, empty stomach, rapid sequence induction, inhalational induction, oxygen, sevoflurane, nondepolarizing relaxant, controlled ventilation, awake extubation, wound infiltration, bupivacaine, paracetamol, apnea

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 

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