Outcomes of Infantile Hypertrophic Pyloric Stenosis at Tertiary Care Centre

Introduction

Infantile hypertrophic pyloric stenosis (IHPS) is a common infantile disorder characterized by enlarged pyloric musculature resulting in obstruction of gastric outlet.¹ IHPS occurs in 1–4 in 1000 births, although rates and trends vary markedly from region to region.²

Its etiological factors are unclear and includes environmental and genetic components. Male gender and a family history are commonly reported risk factors and indicate a genetic factor to the etiology.³

IHPS is usually diagnosed by abdominal ultrasound, on which it is illustrated by increased thickness, length and diameter of pyloric muscle.^4,5 Extramucosal pyloromyotomy, which was introduced by Ramstedt in 1912, remains the gold standard for surgical management of IHPS.⁶

This study describes our experience on the management of infantile hypertrophic pyloric stenosis in our local setting delineating the clinical presentation, mode of treatment and outcome of treatment of this disease.

Methods

This prospective observational study was conducted in our institute over a period of three years from February 2017 to January 2020. Fifty infants presented with diagnosis of Idiopathic hypertrophic pyloric stenosis who subsequently underwent surgical procedure were included in the study.

Infants managed with medical management with injection Atropine or with multiple anomalies were excluded from the study. Parental consent was taken for inclusion in the study.

The diagnosis of IHPS was made clinically by the typical clinical presentation of non-bilious vomiting, gastric peristalsis or palpable pyloric mass and was confirmed with ultrasound. In abdominal ultrasound, IHPS was characterized by increased pyloric muscle thickness ≥3 mm and pyloric channel length 14 mm or greater. Dehydration was defined based on sunken fontanelle, dry mucous membranes, poor skin turgor and lethargy.

Clinical presentation, electrolyte abnormalities on admission, ultrasound findings, treatment and outcomes of treatment, postoperative complications, length of hospital stay and mortality were recorded in the study.

All infants were first resuscitated with 1/2 normal saline and KCl (Potassium chloride). After electrolyte correction, Ramstedt’s pyloromyotomy surgery was performed for every infant.

The data was entered and analyzed in Epi Info version 7 software. Categorical variables were analyzed as percentages and quantitative variables were analyzed as mean with standard deviation (SD), or median with inter-quartile range (IQR) according to the distribution of the variable.

Results

Total fifty IHPS infants were admitted and operated during the period of study. Out of 50 infants, 42 (84%) were males and 8 (16%) were females, with a male to female ratio of 5.2:1. Mean birth weight of infants was 3.1 ± 1.4 kg. Thirty (60%) infants were first-born children.

There were 14 (28%) infants who started vomiting very early during the first week of life, while 30 (60%) became symptomatic within one month of age. Only six (12%) patients became symptomatic after one month of age. The mean age at presentation was 5.2 ± 1.2 weeks with a range of 8 days to 12 weeks. The youngest child operated on was two weeks old and the oldest was 12 weeks with the median age of five weeks.

Progressive non-bilious vomiting was the most frequent symptom and it was described in all the (100%) patients. Visible peristalsis was seen in 40 (80%) infants and palpable mass was found in 30 (60%) infants (Table 1).

Metabolic alkalosis was seen in 32 (64%) infants. Electrolyte abnormality was seen in 38 (76%) infants in which hyponatremia was seen in 25 (50%), hypokalemia was seen in 32 (64%) and hypochloremia was seen in 28 (56%) infants (Table 2).

On ultrasound examination, mean thickness (Figure 1) of pyloric circular muscle was 5.2 ± 1 mm (range 3-8 mm) and length of pyloric muscle (Figure 2) was ranging from 14 to 38 mm with a mean of 20.1 ± 3 mm. No patient required any other diagnostic investigation for confirmation of diagnosis.

All infants were first resuscitated with 1/2 normal saline and KCl (Potassium chloride). After electrolyte correction, Ramstedt’s pyloromyotomy surgery was done in every infant (Figure 3). The mean duration of time taken for the dehydration and electrolyte imbalance to be corrected before the surgery was 1.39 ± 0.5 days (range of 1–2 days) and the mean duration of hospital stay was 4.36 ± 0.59 days (range of 4–6 days). The feeding was initiated after 12 – 24 hours after the surgery. Twelve (29.55%) infants had regurgitation and vomiting for 2–3 days after initiation of feeding which was self-limiting.

Most common complication after surgery was septicemia followed by postoperative vomiting and wound infection (Table 3). No mortality was reported in our study

Discussion

Infantile hypertrophic pyloric stenosis (IHPS) has been reported to be the most common cause of gastric outlet obstruction in infancy and the most common surgical cause of vomiting.¹

In our study, the males were more affected than females with a male to female ratio of 5.2:1, which is comparable to the global ratio of 4:1–6:1.7,8,9 Our study showed higher rate of IHPS in the first born male infants (60%) which was also seen in other similar studies.^3,10

The mean age of presentation was 5.2 weeks which was delayed presentation than some of the other studies.^3,8,11 This could be due to lack of awareness of parents to consider vomiting as a minor symptom, or misdiagnosis of the disease. Delay in diagnosis can result in significant electrolyte imbalance, weight loss, and failure to thrive.⁴

In our study, non-bilious vomiting was most predominant symptom seen in all the infants (100%). The classic presentation of an olive mass in the epigastric region on palpation was seen in 60% of the cases which was comparable with other studies.^3,8

In infants with IHPS, due to ongoing vomiting for several days, serum electrolytes are commonly deranged. The nature of derangement is a spectrum, ranging from mild to severe hyponatraemia, hypochloraemia, hypokalaemia, and metabolic alkalosis.^3,4 In the current study, serum electrolytes results revealed hypokalaemia (64%), hyponatraemia (50%) and hypochloraemia (56%) which is an expected occurrence in untreated cases. When this derangement occurs, it should be corrected before surgical treatment.

Mucosal perforation is a rarest complication of Ramstedt’s pyloromyotomy and is usually due to extending the myotomy beyond the pyloric–duodenal junction. When this occurs, repair is done by using interrupted absorbable sutures and covered with omentum.^6,12 However in our study, no complication of intraoperative mucosal perforation had occurred.

In this study, most common complication after surgery was septicemia, followed by postoperative vomiting, wound infection. All the postoperative complications were treated conservatively.

The mean duration of hospital stay was 4.36 ± 0.59 days, which was comparable with most published data in the literature.^6,8,11,13

Mortality after pyloromyotomy is less than 0.4% in most major centers and when it occurs, it is usually from fluid and electrolyte depletion in infants presenting late, and due to inadequately corrected electrolyte problems before surgery.^3,14 However in our study, no mortality occurred during the study period. Delayed presentation, dehydration and electrolyte disturbances, sepsis, surgical site infection were the main predictors of poor outcome.

This study was done in a single center and the number of patients enrolled were less, which was the limitation of this study. Hence multicentric studies with large number of patients are required to generalize the results.

Conclusion

High index of suspicion is required in infants with nonbilious vomiting to avoid delay in diagnosis and its sequelae like dehydration and electrolyte imbalance. Prompt correction of the fluid and electrolyte disturbances after diagnosis shortens preoperative hospital stay.

Source of Financial Support

Nil.

Conflict of Interest

None.