Pediatric Hypertrophic Pyloric Stenosis Treatment & Management

• Surgical repair of hypertrophic pyloric stenosis (HPS) is fairly straightforward and without many complications, yet properly preparing the infant for this procedure is vitally important. Most infants with hypertrophic pyloric stenosis do not have complete gastric outlet obstruction and can tolerate their inherent gastric secretions.
• Repeated episodes of vomiting following attempts to feed the infant cause progressive dehydration and loss of hydrogen chloride from the gastric juices. Preoperative management is directed at correcting the fluid deficiency and electrolyte imbalance.

  • Base fluid resuscitation on the infant's degree of dehydration. Most infants can have their fluid status corrected within 24 hours; however, severely dehydrated children sometimes require several days for correction.
  • If necessary, administer an initial fluid bolus of 10 mL/kg with lactated Ringer solution or 0.45 isotonic sodium chloride solution. Continue intravenous (IV) therapy at an initial rate of 1.25-2 times the normal maintenance rate until adequate fluid status is achieved.
  • Adequate amounts of both chloride and potassium are necessary to correct metabolic acidosis. Unless renal insufficiency is a concern, initially add 2-4 mEq of KCL per 100 mL of IV fluid. Adequate chloride for resuscitation can usually be provided by 5% dextrose in 0.4% sodium chloride solution. Avoid adding hypertonic chloride or ammonium chloride.
  • Urine output and serial electrolyte determinations are performed during resuscitation. Correction of serum chloride level to 90 mEq/L or greater is usually adequate to proceed with surgical intervention.
  • Before induction of anesthesia, aspirate the infant's stomach with a large-caliber suction tube to remove any residual gastric fluid or barium. Saline irrigation is occasionally necessary to remove a large quantity of barium.

Pyloromyotomy remains the standard of treatment, and outcome is excellent.^[5] The best surgical outcome and lowest complications are more likely when the surgeon has specialist pediatric surgical training.

• Ramstedt pyloromyotomy remains the standard procedure of choice for hypertrophic pyloric stenosis because it is easily performed and is associated with minimal complications. The usual approach is via a right upper quadrant transverse incision that splits the rectus muscle and fascia.
• Some authorities report that laparoscopic pyloromyotomy has a significantly shorter recovery time compared with open pyloromyotomy but that open pyloromyotomy has higher efficacy and fewer complications. However, a small (N=98) 2011 prospective, randomized trial found no difference in operating time, length of stay, or difference in time to full feeds between open and laparoscopic pyloromyotomy. While complication rates were similar between the 2 groups, significantly superior long-term cosmetic results were noted in the laparoscopic group.^[6]
• Endoscopic pyloromyotomy is a simple procedure and can be performed as an outpatient procedure.
• Recently, endoscopic balloon dilatation of hypertrophic pyloric stenosis after failed pyloromyotomy has been used with greater frequency.
• Several other approaches have been described. A supraumbilical curvilinear approach has gained popularity with good cosmetic results.
• Postoperative management

  • Continue IV maintenance fluid until the infant is able to tolerate enteral feedings. In most instances, feedings can begin within 8 hours following surgery. Graded feedings can usually be initiated every 3 hours, starting with Pedialyte and progressing to full-strength formula.
  • Although schedules that advance the volume of feeds more quickly or those that begin with ad lib feeds are associated with more frequent episodes of vomiting, they do not increase morbidity and actually may decrease the time to hospital discharge.
  • Addition of a histamine 2 (H2) receptor blocker sometimes can be beneficial.
  • Treat persistent vomiting expectantly because it usually resolves within 1-2 days.
  • Avoid the temptation to repeat ultrasonography or UGI barium study; these invariably demonstrate a deformed pylorus and results are difficult to interpret.

Early consultation with a surgeon familiar with neonatal care is warranted because treatment is essentially surgical. Early consults facilitate decisions for diagnostic studies, fluid resuscitation, and scheduling the operative procedure. This is especially important if the child requires transfer to another facility for surgical care. The American Pediatric Surgical Association offers guidelines for appropriate consultation and transfer of small infants. Good outcome has been shown to depend on the quality of preoperative correction of fluid and electrolyte abnormalities, availability of a pediatric anesthetist, and training level of the surgeon.

Feedings are usually resumed 6-8 hours after operation.^[7] In most instances, gradually increasing the volume and strength of feedings is recommended (see Surgical Care).