Infantile hypertrophic pyloric stenosis 2

[TREATMENT — Definitive management of IHPS is surgery. However, conservative management of infants with IHPS also has been described. This approach typically involves a trial of continuous nasoduodenal feedings, generally lasting several months, until the obstructive process becomes less significant as the infant gains weight [ 70]. Oral and intravenous atropine sulfate (which relaxes the pyloric musculature) also have been described but are uncommonly used [ 71-74]. Because of the safety and efficacy of surgery, conservative management should be reserved for infants in whom a surgical approach is either not advisable or feasible.

The timing of surgery depends upon the clinical status of the infant. If the diagnosis is made early and the child is well-hydrated with normal electrolytes, surgery may take place on the day of diagnosis [ 75]. Surgery should be delayed in the setting of dehydration and/or electrolyte derangements [ 76].
Infants presenting with normal electrolyte values and mild dehydration, as is the case with more than 60 percent of patients, should receive maintenance intravenous fluids such as 5 percent dextrose with 0.25 percent NaCl and 2 meq KCl per 100 mL. Infants with moderate or severe dehydration require more involved fluid management with higher NaCl concentrations (0.5 percent to normal saline) and higher rates of administration (1.5 to 2 times maintenance), perhaps combined with bolus administration initially. Caution must be taken in the more severely dehydrated infants to ensure the kidneys are functional prior to the addition of KCl to the intravenous fluids. The correction of alkalosis prior to surgery is imperative because alkalosis has been associated with an increased risk of post-operative apnea [ 77].
The classical operation for IHPS is Ramstedt pyloromyotomy, which involves a longitudinal incision of the hypertrophic pylorus, with blunt dissection to the level of the submucosa; it relieves the constriction and allows normal passage of stomach contents into the duodenum. Laparoscopic pyloromyotomy is a minimally invasive version of the Ramstedt procedure [ 78,79] that has been associated with a lower incidence of postoperative emesis and a shorter hospital stay ( show figure 3) [ 80].

The two procedures were compared in a prospective trial in which 200 infants with ultrasonographically confirmed IHPS were randomly assigned to open or laparoscopic pyloromyotomy [ 81]. There were no differences between groups in operating time, time to full feeding, or length of stay. However, infants in the laparoscopic group had fewer episodes of emesis (2.6 versus 1.9) and received fewer doses of analgesia (2.2 versus 1.6) than those in the open group.
Endoscopically-guided balloon dilation for IHPS has been described [ 82]. However, because balloon dilatation does not reliably disrupt the seromuscular ring [ 83], attempts at this technique are best reserved for patients in whom general anesthesia would pose a significant risk or in whom a surgical approach to the pylorus is not possible.
The complication rate from pyloromyotomy is exceedingly low, particularly given its impact on the mortality of IHPS. A review of cases from the Royal Hospital for Sick Children in Glasgow, Scotland showed a decrease in mortality from 59 percent in 1925 to 0 percent in 1975 [ 84]. Another report showed that 40 of 901 (4 percent) infants who underwent pyloromyotomy had an intraoperative complication, with 39 of these being a duodenal perforation, all of which were recognized. Fifty-two infants (6 percent) had post-operative complications, with wound infection in fewer than 1 percent and vomiting in 3 percent [ 85]. An earlier study cited its most frequent complications as GER (11 percent), duodenal perforation (8 percent), and wound infection (5 percent) [ 33]. The incidence of wound dehiscence and bleeding is very low [ 86].
Although post-operative vomiting is fairly infrequent, the incidence of modest regurgitation can be as high as nearly 80 percent [ 6], and its presence should not delay the institution of post-operative feedings. In one report, infants offered ad-lib feedings four hours after operation, despite having slightly more emesis episodes, tolerated full feedings sooner than did infants receiving an incremental feeding schedule [ 87]. Radiologic evaluation should be performed if vomiting persists beyond five days post-operatively [ 85], with the understanding that interpretation of the study may be difficult because of post-operative swelling.