Infantile hypertrophic pyloric stenosis: a comparative study of incidence and other epidemiological characteristics in seven European regions

Evaluation of the learning curve for laparoscopic pyloromyotomy

BACKGROUND

Laparoscopic pyloromyotomy is the preferred surgical management of hypertrophic pyloric stenosis at most centers. We aimed to analyze the learning curve for laparoscopic pyloromyotomy using the experience of five fellowship-trained pediatric surgeons.

METHODS

A retrospective review of consecutive patients undergoing laparoscopic pyloromyotomy was performed. All cases were performed with general surgery residents. Cumulative sum (CUSUM) analysis for operating time was performed for up to the first 150 consecutive cases for individual surgeons. Outcomes were compared to identify different phases of the learning curve for operative competency.

RESULTS

A total of 414 patients were included in the analysis as not all surgeons had reached 150 cases at time of analysis. The mean operating time was 29.2 min for all cases across the 5 surgeons. CUSUM analysis for mean operating time revealed three phases of learning: Learning Phase (cases 1-16), Plateau Phase (cases 17-87), and a Proficiency Phase (cases 88-150). The mean operating time during the three phases was 34.1, 29.0, and 28.3 min, respectively (P = 0.005). There were no differences in complications, reoperations, length of stay, or readmissions across the three phases.

CONCLUSION

Three distinct phases of learning for laparoscopic pyloromyotomy were identified with no differences in outcomes across the phases. The operating time differed only for the Learning Phase, suggesting that some degree of proficiency occurs after 16 cases.

Perinatal risk factors for infantile hypertrophic pyloric stenosis: A systematic review and meta-analysis

BACKGROUND

Infantile hypertrophic pyloric stenosis (IHPS) is one of the most common diseases that require surgical intervention amongst the paediatric population. Although the treatment and the diagnosis of pyloric stenosis are well established, the perinatal risk factors associated with it still need further investigation.

METHODS

We searched the following databases: Cochrane, Google Scholar, PubMed, and Scopus. Studies were included if they were case-control or cohort in design and studied the perinatal risk factors associated with IHPS. The quality of the included studies was assessed using the Newcastle-Ottawa scale (NOS).

RESULTS

Twenty-one articles were included in this meta-analysis, including 18,104,753 participants. Our analysis showed a significant association between IHPS and male sex (RR=2.71, 95% CI:1.93-3.78), maternal smoking (RR=1.75, 95% CI: 1.54 - 2.00), bottle-feeding (RR=1.68, 95% CI: 1.42 - 1.98), being first born (RR=1.23, 95% CI:1.07-1.40), African ethnicity (RR=0.51, 95% CI: 0.35-0.75), and cesarean section (RR=1.57, 95% CI: 1.49-1.66). On the contrary, there was no significant association between IHPS and multiple gestations, preterm labour, being born in summer, and small for gestational age (SGA).

CONCLUSION

In conclusion, our analysis showed that male sex, bottle feeding, maternal smoking and African ethnicity were significantly associated with the risk of IHPS. However, most of the included articles were retrospective in design which necessitates conducting future prospective well-designed studies to further investigate the risk factors of IHPS.

Factors associated with pyloric hypertrophy severity and post-operative feeding and nutritional recovery in infantile hypertrophic pyloric stenosis

BACKGROUND

To examine factors that affect the severity of pyloric hypertrophy, post-operative feeding and nutritional recovery in infantile hypertrophic pyloric stenosis (IHPS).

METHODS

Medical records of infants diagnosed with IHPS at a single tertiary center between 2009 and 2018 were retrospectively reviewed. Clinical characteristics, biochemistry data and outcome were assessed for their association with the severity of pyloric hypertrophy and post-operative recovery. Nutritional recovery was assessed using weight-for-age status improvement after surgery.

RESULTS

Eighty-five patients were recruited in this study. The mean pre-operative weight-for-age percentile was 18.2. Elevated bicarbonate was positively correlated with symptom duration (p = 0.007). Pyloric muscle thickness was significantly correlated with age, weight, and symptom duration (p = 0.004, 0.003, 0.008, respectively). The mean weight-for-age percentile increased to 41.6 by post-operative weeks 6-8. Pyloric muscle thickness was negatively correlated with nutritional recovery by post-operative weeks 6-8 (p = 0.003). In multivariable analysis, pyloric length related to nutritional recovery at week 1-2 postoperatively (OR = 1.42, p = 0.030, 95% CI = 0.03-1.94), and pyloric muscle thickness related to nutritional recovery at week 6-8 postoperatively (OR = 4.08, p = 0.032, 95% CI = 1.13-14.7).

CONCLUSION

Our study indicated that favorable nutritional outcome and successful weight gain was observed 6-8 weeks after surgery in children with IHPS. Pyloric muscle thickness positively correlated with age, weight, symptom duration, and favorable nutritional recovery. Serum bicarbonate showed a positive correlation with symptom duration.

Environmental exposure in the etiology of infantile hypertrophic pyloric stenosis: a systematic review and meta-analysis

PURPOSE

To investigate the occupational and environmental factors in the etiology of infantile hypertrophic pyloric stenosis (IHPS).

METHODS

Protocol was drafted according to the PRISMA guidelines and registered on PROSPERO (CRD42020152460). A search for a combination of terms related to IHPS, fetus and neonates, and environmental exposure was performed for studies published between 2000 and 2020 in the EMBASE, Pubmed, and MEDLINE databases.

RESULTS

Overall, 2203 abstracts were identified and 829 were screened. The full text of the selected articles (N = 98) was assessed for eligibility. Fifteen studies were included in quantitative synthesis. IHPS risk was significantly lower in black and Hispanic mothers than in white mothers [OR 0.47 (95% CI 0.44-0.51, p < 0.001), OR 0.85 (95% CI 0.77-0.94, p = 0.002), respectively]. Lower maternal education level and maternal smoking were risk factor for IHPS. We further observed a non-significant association between maternal folic acid usage and IHPS risk. Data were insufficient to evaluate occupational exposure.

CONCLUSION

This review provides an understanding of the role of environmental exposures in IHPS etiology. Lower maternal educational level, maternal smoking, and white ethnicity are associated with a significantly increased risk of IHPS, while folic acid use seems non-significantly associated with IHPS risk.

LEVEL OF EVIDENCE

III.

Case report: Late-onset hypertrophic pyloric stenosis in a 3-year-old boy: It is never too late

Hypertrophic Pyloric Stenosis (HPS) represents a relatively rare occurrence beyond infancy. Here, we present the case of a barely 3-year-old boy diagnosed with late-onset HPS and successfully treated with extra-mucosal pyloromyotomy. We review the literature, challenging the principle that more aggressive surgical approaches should be preferred over less invasive ones.

The Dutch Incidence of Infantile Hypertrophic Pyloric Stenosis and the Influence of Seasons

INTRODUCTION

 Studies report contradicting results on the incidence of infantile hypertrophic pyloric stenosis (IHPS) and its association with seasons. We aim to assess the IHPS incidence in the Netherlands and to determine whether seasonal variation is present in a nationwide cohort.

MATERIALS AND METHODS

 All infants with IHPS hospitalized in the Netherlands between 2007 and 2017 were included in this retrospective cohort study. Incidence rates per 1,000 livebirths (LB) were calculated using total number of LB during the matched month, season, or year, respectively. Seasonal variation based on month of birth and month of surgery was analyzed using linear mixed model and one-way ANOVA, respectively.

RESULTS

 A total of 2,479 infants were included, of which the majority was male (75.9%). Median (interquartile range) age at surgery was 34 (18) days. The average IHPS incidence rate was 1.28 per 1,000 LB (variation: 1.09-1.47 per 1,000 LB). We did not find a conclusive trend over time in IHPS incidence. Differences in incidence between season of birth and season of surgery were not significant (p = 0.677 and p = 0.206, respectively).

CONCLUSION

 We found an average IHPS incidence of 1.28 per 1,000 LB in the Netherlands. Our results showed no changing trend in incidence and no seasonal variation.

Infantile hypertrophic pyloric stenosis in Bosnia and Herzegovina: A retrospective cohort study from the largest tertiary care facility

BACKGROUND

Infantile hypertrophic pyloric stenosis (IHPS) is the most common condition requiring surgery in infancy, but the etiology of IHPS is still unclear. The study aimed to analyze the epidemiological and clinical features of the infants with IHPS in our setting and determine the yearly trends in IHPS incidence in the Sarajevo Canton between 2007 and 2016.

METHODS

We retrospectively analyzed epidemiologic, clinical, and operative data of all infants undergoing pyloromyotomy for IHPS over ten years in the largest tertiary care facility in Bosnia and Herzegovina.

RESULTS

Fifty-three IHPS patients were diagnosed, yielding an overall incidence of 1.17 per 1000 live births (1.25 and 1.09 cases in 2007-2011 and 2012-2016, respectively). IHPS was more prevalent among male infants (ratio 6.6:1, p < 0.001). The mean age at onset of symptoms was 39.6 days (range, 17-107 days). The estimated median time from symptoms onset to hospitalization was 11 days (range, 1-17 days). The mean age at diagnosis was significantly longer in premature infants compared with term infants (p = 0.003). Both first-born rank and bottle-feeding were significantly associated with IHPS (p = 0.001 and p = 0.04, respectively). No seasonal variation associated with IHPS was detected (p = 0.25). No evidence was found of differences in the incidence of IHPS related to maternal age (p = 0.24) and smoking (p = 0.59).

CONCLUSION

Our data indicate a declining trend and provide insights into the clinical characteristics of IHPS in Bosnia and Herzegovina. Most of the obtained results are in line with the published data and could improve the quality of local pediatric services.

The incidence of infantile hypertrophic pyloric stenosis nearly halved from 2005 to 2017: analysis of German administrative data

PURPOSE

Some paediatric surgical diseases showed a declining incidence in recent years, among which hypertrophic pyloric stenosis has been particularly striking shortly in the years after the millennium. We aimed to assess whether this development continued over the following decade, as it might offer the chance to better understand the underlying reasons.

METHODS

We analysed data files obtained from the German federal statistics office for principal diagnosis of hypertrophic pyloric stenosis and pyloromyotomies from 2005 to 2017. Changes over time were assessed via linear regression for incidences per 1000 live births.

RESULTS

In the respective time interval, there were a mean of 1009 pyloromyotomies (95% CI 906-1112) per year, of which a mean of 835 (95% CI 752-917) were performed in boys. The incidence of hypertrophic pyloric stenosis per 1000 live births almost halved between 2005 and 2017: it decreased by 0.12 pylorotomies annually (95% CI 0.09-0.14; P < 0.0001) in boys-from a maximum of 2.96 to a minimum of 1.63-and 0.03 pyloromyotomies annually (95% CI 0.02-0.04; P < 0.0001) in girls-from a maximum of 0.64 to a minimum of 0.28. There was considerable regional variation in incidences between the German länder.

CONCLUSION

The decreasing incidence of hypertrophic pyloric stenosis noted around the millenium continued into the following decades. The underlying reasons are unclear, which should prompt further research on the subject matter.

Open versus laparoscopic pyloromyotomy for pyloric stenosis

BACKGROUND

Infantile hypertrophic pyloric stenosis (IHPS) is a disorder of young children (aged one year or less) and can be treated by laparoscopic (LP) or open (OP) longitudinal myotomy of the pylorus. Since the first description in 1990, LP is being performed more often worldwide.

OBJECTIVES

To compare the efficacy and safety of open versus laparoscopic pyloromyotomy for IHPS.

SEARCH METHODS

We conducted a literature search on 04 February 2021 to identify all randomised controlled trials (RCTs), without any language restrictions. We searched the following electronic databases: MEDLINE (1990 to February 2021), Embase (1990 to February 2021), and the Cochrane Central Register of Controlled Trials (CENTRAL). We also searched the Internet using the Google Search engine (www.google.com) and Google Scholar (scholar.google.com) to identify grey literature not indexed in databases.

SELECTION CRITERIA

We included RCTs and quasi-randomised trials comparing LP with OP for hypertrophic pyloric stenosis.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references and extracted data from trial reports. Where outcomes or study details were not reported, we requested missing data from the corresponding authors of the primary RCTs. We used a random-effects model to calculate risk ratios (RRs) for binary outcomes, and mean differences (MDs) for continuous outcomes. Two review authors independently assessed risks of bias. We used GRADE to assess the certainty of the evidence for all outcomes.

MAIN RESULTS

The electronic database search resulted in a total of 434 records. After de-duplication, we screened 410 independent publications, and ultimately included seven RCTs (reported in 8 reports) in quantitative analysis. The seven included RCTs enrolled 720 participants (357 with open pyloromyotomy and 363 with laparoscopic pyloromyotomy). One study was a multi-country trial, three were carried out in the USA, and one study each was carried out in France, Japan, and Bangladesh. The evidence suggests that LP may result in a small increase in mucosal perforation compared with OP (RR 1.60, 95% CI 0.49 to 5.26; 7 studies, 720 participants; low-certainty evidence). LP may result in up to 5 extra instances of mucosal perforation per 1,000 participants; however, the confidence interval ranges from 4 fewer to 44 more per 1,000 participants. Four RCTs with 502 participants reported on incomplete pyloromyotomy. They indicate that LP may increase the risk of incomplete pyloromyotomy compared with OP, but the confidence interval crosses the line of no effect (RR 7.37, 95% CI 0.92 to 59.11; 4 studies, 502 participants; low-certainty evidence). In the LP groups, 6 cases of incomplete pyloromyotomy were reported in 247 participants while no cases of incomplete pyloromyotomy were reported in the OP groups (from 255 participants). All included studies (720 participants) reported on postoperative wound infections or abscess formations. The evidence is very uncertain about the effect of LP on postoperative wound infection or abscess formation compared with OP (RR 0.59, 95% CI 0.24 to 1.45; 7 studies, 720 participants; very low-certainty evidence). The evidence is also very uncertain about the effect of LP on postoperative incisional hernia compared with OP (RR 1.01, 95% CI 0.11 to 9.53; 4 studies, 382 participants; very low-certainty evidence). Length of hospital stay was assessed by five RCTs, including 562 participants. The evidence is very uncertain about the effect of LP compared to OP (mean difference -3.01 hours, 95% CI -8.39 to 2.37 hours; very low-certainty evidence). Time to full feeds was assessed by six studies, including 622 participants. The evidence is very uncertain about the effect of LP on time to full feeds compared with OP (mean difference -5.86 hours, 95% CI -15.95 to 4.24 hours; very low-certainty evidence). The evidence is also very uncertain about the effect of LP on operating time compared with OP (mean difference 0.53 minutes, 95% CI -3.53 to 4.59 minutes; 6 studies, 622 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Laparoscopic pyloromyotomy may result in a small increase in mucosal perforation when compared with open pyloromyotomy for IHPS. There may be an increased risk of incomplete pyloromyotomy following LP compared with OP, but the effect estimate is imprecise and includes the possibility of no difference. We do not know about the effect of LP compared with OP on the need for re-operation, postoperative wound infections or abscess formation, postoperative haematoma or seroma formation, incisional hernia occurrence, length of postoperative stay, time to full feeds, or operating time because the certainty of the evidence was very low for these outcomes. We downgraded the certainty of the evidence for most outcomes due to limitations in the study design (most outcomes were susceptible to detection bias) and imprecision. There is limited evidence available comparing LP with OP for IHPS. The included studies did not provide sufficient information to determine the effect of training, experience, or surgeon preferences on the outcomes assessed.

Integrating genetics with newborn metabolomics in infantile hypertrophic pyloric stenosis

INTRODUCTION

Infantile hypertrophic pyloric stenosis (IHPS) is caused by hypertrophy of the pyloric sphincter muscle.

OBJECTIVES

Since previous reports have implicated lipid metabolism, we aimed to (1) investigate associations between IHPS and a wide array of lipid-related metabolites in newborns, and (2) address whether detected differences in metabolite levels were likely to be driven by genetic differences between IHPS cases and controls or by differences in early life feeding patterns.

METHODS

We used population-based random selection of IHPS cases and controls born in Denmark between 1997 and 2014. We randomly took dried blood spots of newborns from 267 pairs of IHPS cases and controls matched by sex and day of birth. We used a mixed-effects linear regression model to evaluate associations between 148 metabolites and IHPS in a matched case-control design.

RESULTS

The phosphatidylcholine PC(38:4) showed significantly lower levels in IHPS cases (P = 4.68 × 10^-8) as did six other correlated metabolites (four phosphatidylcholines, acylcarnitine AC(2:0), and histidine). Associations were driven by 98 case-control pairs born before 2009, when median age at sampling was 6 days. No association was seen in 169 pairs born in 2009 or later, when median age at sampling was 2 days. More IHPS cases than controls had a diagnosis for neonatal difficulty in feeding at breast (P = 6.15 × 10^-3). Genetic variants known to be associated with PC(38:4) levels did not associate with IHPS.

CONCLUSIONS

We detected lower levels of certain metabolites in IHPS, possibly reflecting different feeding patterns in the first days of life.

Guidelines of the Italian Society of Videosurgery (SIVI) in Infancy for the minimally invasive treatment of Hypertrophic Pyloric Stenosis in neonates and infants

The most appropriate treatment for the infantile Hypertrophic Pyloric Stenosis (HPS) is still debated. The non-surgical conservative treatment with oral or intravenous administration of atropine does not enjoy a widespread appreciation for several factors (...).

Does Maternal Omega 3 Supplementation Protect Against Infantile Hypertrophic Pyloric Stenosis?

OBJECTIVES

Infantile hypertrophic pyloric stenosis (IHPS) is potentially life threatening. The etiology of IHPS remains unknown and many risk factors have been reported. We aimed to assess the prevalence of known risk factors and investigate maternal nutrition and habits as possible additional risk factors for IHPS.

METHODS

This case-control study includes mothers of infants diagnosed with IHPS and control mothers of infants, age 2 to 11 months, hospitalized in the pediatric department due to other conditions. Cases of IHPS were identified by review of all infants diagnosed with IHPS and operated upon in 2010 to 2016 at 2 major hospitals in central Israel. Data regarding potential risk factors were collected via questionnaires in both study groups.

RESULTS

Sixty-six cases and 67 controls were included in the study. Maternal omega 3 supplement consumption during pregnancy was significantly less common among cases of IHPS as compared with controls (P = 0.031). Consumption of omega 3 supplement was defined as consumption of at least 1 to 2 per week during the pregnancy period. Following adjustment for known risk factors, including male sex and maternal smoking, maternal omega 3 supplement consumption remained associated with a significantly lower risk of developing IHPS (odds ratio = 0.303, 95% confidence interval 0.111-0.828, P = 0.02).

CONCLUSIONS

Maternal omega 3 supplement consumption during pregnancy was associated with a significantly reduced risk of IHPS. Further studies are needed to support these results and investigate possible mechanisms of the effect of omega 3.

Declining incidence of pyloric stenosis in New Zealand

BACKGROUND

Pyloric stenosis is a relatively common paediatric surgical condition, but a worldwide decline in its incidence has been observed in recent decades. The objective of this study was to identify if the incidence of pyloric stenosis in New Zealand has been declining.

METHODS

A retrospective review of the four New Zealand paediatric surgical centres' theatre databases from 2007 to 2017. Demographic data were recorded for all infants who had a pyloromyotomy and annual incidences of pyloric stenosis calculated.

RESULTS

A total of 393 infants underwent a pyloromyotomy for pyloric stenosis during the study period. Most infants (81%) were of European ethnicity. There was a significant decline (P = 0.0001) in the national incidence of pyloric stenosis from 0.73/1000 live births (LB) in 2007 to 0.39/1000 LB in 2017. From 2007 to 2017, the incidence of male infants with pyloric stenosis declined from 1.27/1000 LB to 0.62/1000 LB. The current annual incidence of pyloric stenosis in New Zealand is 0.39/1000 LB.

CONCLUSIONS

The incidence of pyloric stenosis in New Zealand has significantly declined in the last decade and is currently the lowest reported incidence in the world involving a predominantly European cohort. A decline in male infants developing pyloric stenosis was also observed. Further study is required to investigate causes for this low incidence and declining trend.

Genome-wide meta-analysis identifies BARX1 and EML4-MTA3 as new loci associated with infantile hypertrophic pyloric stenosis

Infantile hypertrophic pyloric stenosis (IHPS) is a disorder of young infants with a population incidence of ∼2/1000 live births, caused by hypertrophy of the pyloric sphincter smooth muscle. Reported genetic loci associated with IHPS explain only a minor proportion of IHPS risk. To identify new risk loci, we carried out a genome-wide meta-analysis on 1395 surgery-confirmed cases and 4438 controls, with replication in a set of 2427 cases and 2524 controls. We identified and replicated six independent genomic loci associated with IHPS risk at genome wide significance (P < 5 × 10-8), including novel associations with two single nucleotide polymorphisms (SNPs). One of these SNPs, rs6736913 [odds ratio (OR) = 2.32; P = 3.0 × 10-15], is a low frequency missense variant in EML4 at 2p21. The second SNP, rs1933683 (OR = 1.34; P = 3.1 × 10-9) is 1 kb downstream of BARX1 at 9q22.32, an essential gene for stomach formation in embryogenesis. Using the genome-wide complex trait analysis method, we estimated the IHPS SNP heritability to be 30%, and using the linkage disequilibrium score regression method, we found support for a previously reported genetic correlation of IHPS with lipid metabolism. By combining the largest collection of IHPS cases to date (3822 cases), with results generalized across populations of different ancestry, we elucidate novel mechanistic avenues of IHPS disease architecture.

Co-occurrence of infantile hypertrophic pyloric stenosis and congenital heart defects: a nationwide cohort study

BACKGROUND

Recent studies suggest that infantile hypertrophic pyloric stenosis (IHPS) and congenital heart defects (CHDs) may share some genetic risk factors, but little is known about the co-occurrence of the two conditions in patients.

METHODS

Our study cohort included 2,212,756 persons born in Denmark 1977-2013. We identified patients with IHPS and CHD in the National Patient Register. Using log-linear Poisson regression, we estimated the (incidence) rate ratios (RRs) comparing the rate of IHPS among children with a CHD diagnosis (exposed) and the rate among those without such a diagnosis.

RESULTS

Twenty-seven thousand three hundred and fifty-seven children in the cohort were diagnosed with CHD out of whom 85 developed IHPS (RR = 2.62, 95% confidence interval (CI) 2.09-3.22]). The results were similar for those with and without other congenital malformations, for preterm and term deliveries, and for both sexes. There was, however, a significant effect of calendar period (P = .003). In the period 1977-1996, the RR of IHPS given a CHD diagnosis was 1.96 (95% CI 1.41-2.64); in the period 1997-2014, the RR was 3.75 (95% CI 2.74-4.99).

CONCLUSION

CHD was associated with an increased risk of IHPS. Further research is needed to delineate molecular-level mechanisms that may affect both conditions.

The incidence of infantile hypertrophic pyloric stenosis and its association with folic acid supplementation during pregnancy: A nested case-control study

BACKGROUND AND RATIONALE

Several studies have suggested that the incidence of infantile hypertrophic pyloric stenosis (IHPS) has decreased in recent decades. This decrement is controversial and not fully explained. Concurrently, there has been a major increase in folic acid consumption by pregnant women to prevent neural tube defects. We aimed to describe IHPS incidence in Israel in recent years and to assess its potential association with folic acid consumption.

METHODS

Using the electronic medical database of a 2.1 million member health organization in Israel, we identified all cases (n = 1899) of IHPS occurring between 1999 and 2015. Cases were individually matched with up to 5 controls (n = 7350) by birth date, sex, and region. Odds ratios and 95% confidence intervals by tertiles of cumulative dose of supplemented folic acid between three months prior to pregnancy and up to birth of index child were calculated using conditional logistic regression.

RESULTS

During the study period IHPS incidence declined from 4.3 in 1999 to 2.1 per 1000 live births in 2015(p < 0.0001). No significant (p = 0.81) association was observed between folic acid intake during pregnancy and risk of IHPS incidence. Preterm birth and infant's use of macrolides during first 3 postnatal months were significantly (p < 0.01) associated with increased risk of IHPS.

CONCLUSIONS

Similar to other countries, IHPS incidence in Israel has decreased in recent years. The decrement cannot be explained by increased use of folic acid.

TYPE OF STUDY

Case Control Study.

LEVEL OF EVIDENCE

Level III.

SUMMARY

Using linkage to a large electronic patient database, this study investigated the association between the decrease in infantile hypertrophic pyloric stenosis and maternal exposure to folic acid during pregnancy.

Prevalence and descriptive epidemiology of infantile hypertrophic pyloric stenosis in the United States: A multistate, population-based retrospective study, 1999-2010

BACKGROUND

Antecedents for infantile hypertrophic pyloric stenosis (IHPS) vary across studies; therefore, we conducted a multistate, population-based retrospective study of the prevalence and descriptive epidemiology of IHPS in the United States (US).

METHODS

Data for IHPS cases (n = 29,554) delivered from 1999-2010 and enumerated from 11 US population-based birth defect surveillance programs, along with data for live births (n = 14,707,418) delivered within the same birth period and jurisdictions, were analyzed using Poisson regression to estimate IHPS prevalence per 10,000 live births. Additional data on deliveries from 1999-2005 from seven of these programs were analyzed using multivariable logistic regression to estimate adjusted prevalence ratios (aPR)s and 95% confidence intervals (CI)s for selected infant and parental characteristics.

RESULTS

Overall, IHPS prevalence from 1999-2010 was 20.09 (95% CI = 19.87, 20.32) per 10,000 live births, with statistically significant increases from 2003-2006 and decreases from 2007-2010. Compared to their respective referents, aPRs were higher in magnitude for males, preterm births, and multiple births, but lower for birth weights <2,500 g. The aPRs for all cases increased with decreasing parental age, maternal education, and maternal parity, but decreased for parental race/ethnicity other than non-Hispanic White. Estimates restricted to isolated cases or stratified by infant sex were similar to those for all cases.

CONCLUSIONS

This study covers one of the largest samples and longest temporal period examined for IHPS in the US. Similar to findings reported in Europe, estimates suggest that IHPS prevalence has decreased recently in the US. Additional analyses supported associations with several infant and parental characteristics.

Infantile Hypertrophic Pyloric Stenosis: An Epidemiological Review

Infantile hypertrophic pyloric stenosis (IHPS) is the most common gastrointestinal disease among infants. IHPS occurs as an isolated condition or together with other congenital anomalies. Association with genetic and environmental factors, bottle feeding, younger maternal age, maternal smoking, and erythromycin administration in the first two weeks of life has been shown. Familial aggregation has been described and a family history is seen in 47.9 percent of siblings. Infants typically present with projectile vomiting associated with symptoms of failure to thrive. An olive-like mass palpable in the right upper abdominal quadrant is being reported less frequently because of earlier diagnosis by ultrasound. IHPS is generally corrected through laparoscopic pyloromyotomy. Endoscopic pyloric balloon dilation is a novel alternative. Further studies on different populations, the general population, and familial segregation to determine the prevalence, influence, and mode of familial aggregation and correlation with environmental factors are needed to determine the etiology of IHPS.

Population-level surgical outcomes for infantile hypertrophic pyloric stenosis

OBJECTIVES

Determine national outcomes for pyloromyotomy; how these are affected by: (i) surgical approach (open/laparoscopic), or (ii) centre type/volume and establish potential benchmarks of quality.

METHODS

Hospital Episode Statistics data were analysed for admissions 2002-2011. Data presented as median (IQR).

RESULTS

9686 infants underwent pyloromyotomy (83% male). Surgery was performed in 22 specialist (SpCen) and 39 nonspecialist centres (NonSpCen). The proportion treated in SpCen increased linearly by 0.4%/year (r=0.76, p=0.01). Annual case volume in SpCen vs. NonSpCen was 40 (24-53) vs. 1 (0-3). Time to surgery was shorter in SpCen (1day [1, 2] vs. 2 [1-3]), but total stay equal (4days [3-6]). 137 (1.4%) had complications requiring reoperation (wound problem 0.6%; repeat pyloromyotomy 0.5% and perforation, bleeding or obstruction 0.2%): pooled rates were similar between SpCen and NonSpCen (1.4% vs. 1.6%, p=0.52). Three NonSpCen had >5% reoperations (within 99.8% C.I. as small denominators). There was no relationship between reoperation and centre volume. Laparoscopic pyloromyotomy had increased risk of repeat pyloromyotomy (OR 2.28 [1.14-4.57], p=0.029).

CONCLUSIONS

Pyloric stenosis surgery shifted from centres local to patients, but outcomes were unaffected by centre type/volume. Modest reported benefits of laparoscopy appear offset by increased reoperations. Quality benchmarks could be set for reoperation <4%.

TYPE OF STUDY

Treatment Study.

LEVEL OF EVIDENCE

Level III.

Pyloric stenosis: an enigma more than a century after the first successful treatment

Despite hypertrophic pyloric stenosis (HPS) being one of the most frequently treated pediatric surgical conditions, its etiology remains incompletely understood. We review the diagnosis and treatment of this condition with an emphasis on the evolution of surgical techniques that led to laparoscopic pyloromyotomy, the most frequently performed technique for HPS today. In addition, we review key developments in the understanding of HPS etiology and treatment, including the postulated etiology of work-induced hypertrophy of the pylorus, its association with prokinetic macrolide antibiotics, and the emerging role of atropine sulfate as a medical treatment for HPS or a rescue treatment for incomplete myotomy.

An overview of concepts and approaches used in estimating the burden of congenital disorders globally

Congenital disorders are an important cause of pregnancy loss, premature death and life-long disability. A range of interventions can greatly reduce their burden, but the absence of local epidemiological data on their prevalence and the impact of interventions impede policy and service development in many countries. In an attempt to overcome these deficiencies, we have developed a tool—The Modell Global Database of Congenital Disorders (MGDb) that combines general biological principles and available observational data with demographic data, to generate estimates of the birth prevalence and effects of interventions on mortality and disability due to congenital disorders. MGDb aims to support policy development by generating country, regional and global epidemiological estimates. Here we provide an overview of the concepts and methodological approach used to develop MGDb.

Post-natal erythromycin exposure and risk of infantile hypertrophic pyloric stenosis: a systematic review and meta-analysis

PURPOSE

Macrolide antibiotics, erythromycin, in particular, have been linked to the development of infantile hypertrophic pyloric stenosis (IHPS). Our aim was to conduct a systematic review of the evidence of whether post-natal erythromycin exposure is associated with subsequent development of IHPS.

METHODS

A systematic review of postnatal erythromycin administration and IHPS was performed. Papers were included if data were available on development (yes/no) of IHPS in infants exposed/unexposed to erythromycin. Data were meta-analysed using Review Manager 5.3. A random effects model was decided on a priori due to heterogeneity of study design; data are odds ratio (OR) with 95 % CI.

RESULTS

Nine papers reported data suitable for analysis; two randomised controlled trials and seven retrospective studies. Overall, erythromycin exposure was significantly associated with development of IHPS [OR 2.45 (1.12-5.35), p = 0.02]. However, significant heterogeneity existed between the studies (I 2 = 84 %, p < 0.0001). Data on erythromycin exposure in the first 14 days of life was extracted from 4/9 studies and identified a strong association between erythromycin exposure and subsequent development IHPS [OR 12.89 (7.67-2167), p < 0.00001].

CONCLUSION

This study demonstrates a significant association between post-natal erythromycin exposure and development of IHPS, which seems stronger when exposure occurs in the first 2 weeks of life.

Contemporary management of pyloric stenosis

Hypertrophic pyloric stenosis is a common surgical cause of vomiting in infants. Following appropriate fluid resuscitation, the mainstay of treatment is pyloromyotomy. This article reviews the aetiology and pathophysiology of hypertrophic pyloric stenosis, its clinical presentation, the role of imaging, the preoperative and postoperative management, current surgical approaches and non-surgical treatment options. Contemporary postoperative feeding regimens, outcomes and complications are also discussed.

Maternal factors in the origin of infantile hypertrophic pyloric stenosis: A population-based case-control study

In most patients affected by isolated infantile hypertrophic pyloric stenosis (IHPS) the etiology is largely unknown. Thus, the aim of this study was to estimate possible maternal risk factors in the origin of IHPS. The study samples included 241 cases with IHPS, 357 matched controls and 38,151 population controls without any defect in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996. Exposures that had been medically recorded in prenatal maternity logbooks during the critical period of IHPS were evaluated separately. The findings of this case-control study suggested that--beyond the well-known robust male excess (85.5%)--maternal hyperthyroidism (OR with 95% CI: 4.17, 1.53-11.38) and oral nalidixic acid treatment (OR with 95% CI: 6.53, 3.03-14.06) associated with a higher risk for IHPS in their children. In conclusion, our findings suggest that cases with IHPS had mothers with a higher proportion of hyperthyroidism and nalidixic acid treatment during pregnancy.

Birth outcomes of male and female patients with infantile hypertrophic pyloric stenosis--a population-based case-control study

OBJECTIVE

Most of the patients are affected by isolated infantile hypertrophic pyloric stenosis (IHPS) beyond the polygenic predisposition, the other factors in the multifactorial etiology are largely unknown. The main characteristic of IHPS is the robust male predominance, thus the aim of this study was to analyze birth outcomes in males and females whether they are different or not.

METHODS

The study samples included 241 cases with IHPS, 357 matched, and 38,151 population controls without any defect in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996.

RESULTS

The findings of this case-control study confirmed the well-known strong male excess (85.5%). The mean gestational age was somewhat longer and it is associated with a lower rate of preterm births. Mean birth weight did not show significant differences among the study groups, but the rate of low birthweight was higher in cases with IHPS. However, these differences were found only in males. Thus, intrauterine fetal growth restriction is characteristic only for male cases with IHPS.

CONCLUSIONS

Our study confirmed the well-known obvious male excess of cases with IHPS, but our findings suggest some differences in birth outcomes of male and female cases. Male cases with IHPS had intrauterine fetal growth restriction while females did not. These data may indicate some differences in the pathogenesis of IHPS in males and females.

Maternal and pregnancy characteristics and risk of infantile hypertrophic pyloric stenosis

BACKGROUND/PURPOSE

The incidence of infantile hypertrophic pyloric stenosis (IHPS) in Sweden decreased dramatically during the 1990s. The aim of the study was to examine IHPS risk factors and the possible change in them as the incidence declined.

METHODS

This is a case-control study including 3608 surgically treated IHPS cases and 17588 matched controls during 1973-2008. Cases were identified in the Swedish National Patient Register and data on possible risk factors were collected from the Swedish Medical Birth Register. The association between study variables and IHPS was analyzed using conditional logistic regression for the whole study period and separately for periods with high and low IHPS incidences.

RESULTS

Prematurity (OR, 2.54; 95% CI, 2.06-3.14), caesarean delivery (OR, 1.67; 95% CI, 1.51-1.86), maternal smoking (OR, 1.82; 95% CI, 1.53-2.16), and young maternal age (< 20yrs) (OR, 1.42; 95% CI, 1.17-1.73) were associated with an increased IHPS risk. Birth order 2 (OR, 0.78; 95% CI, 0.71-0.85) or more was associated with a lower IHPS risk. ORs for smoking increased at low incidence rate.

CONCLUSION

We report caesarean section, prematurity, primiparity, young maternal age, and smoking as significant IHPS risk factors. The impact of smoking was higher during periods with a low incidence.

Advances in infantile hypertrophic pyloric stenosis

Infantile hypertrophic pyloric stenosis (IHPS) is a common condition in infancy, characterized by an acquired narrowing of the pylorus, which requires surgery. These infants usually present with projectile, nonbilious vomiting, with a palpable 'olive' in the abdomen and sometimes a 'peristaltic wave' after being fed with formula or breast milk. Although IHPS is a common disorder, its etiology is largely unknown. Surgical intervention is the standard treatment, preoperative preparation, however is essential to optimal outcome. In this review, the latest advances in IHPS regarding epidemiology, etiology, diagnostics and treatment will be discussed.

Neural stem cell therapies for enteric nervous system disorders

The enteric nervous system is vulnerable to a range of congenital and acquired disorders that disrupt the function of its neurons or lead to their loss. The resulting enteric neuropathies are some of the most challenging clinical conditions to manage. Neural stem cells offer the prospect of a cure given their potential ability to replenish missing or dysfunctional neurons. This article discusses diseases that might be targets for stem cell therapies and the barriers that could limit treatment application. We explore various sources of stem cells and the proof of concept for their use. The critical steps that remain to be addressed before these therapies can be used in patients are also discussed. Key milestones include the harvesting of neural stem cells from the human gut and the latest in vivo transplantation studies in animals. The tremendous progress in the field has brought experimental studies exploring the potential of stem cell therapies for the management of enteric neuropathies to the cusp of clinical application.

The clinical features of infantile hypertrophic pyloric stenosis in Chinese Han population: analysis from 1998 to 2010

Objective

To investigate clinical features of infantile hypertrophic pyloric stenosis (IHPS) in Chinese Han population.

Methods

Three hundred and sixteen hospitalized patients with IHPS from January 1998 to February 2010 were retrospectively reviewed, and data including patient's sex, onset age, other coexisting congenital defects, pyloric circular muscle thickness evaluated by ultrasonograph, serum electrolytes concentration, and results of arterial blood gas analysis on admission were collected. The patients were divided into two groups: the duration between first onset and admission less than or equal to 10 days (early onset group), and more than 10 days (late onset group). The results of arterial blood gas and serum electrolyte concentration were compared between the two groups.

Results

There were 271 males and 45 females in 316 patients; the onset age ranged between 1 and 351 (26.5±26.6) days. The birth weight ranged between 1.6 and 4.5 (3.23±0.44) kilograms; coexisting congenital defects were found in 65 cases (20.6%). Pyloric circular muscle thickness was 4–8 (5.4±1.0) millimetres (mm). For the early onset group, the rates of hypokalemia, hypochloraemia and hypercapnia were significantly lower than those in the late onset group (18.67% VS 50%, P<0.0001; 46.03% VS 71.01%, P = 0.003; 56.58% VS 83.44%, P = 2.17×10⁻⁵; respectively).

Conclusions

The symptom duration in Chinese Han population was longer than that in other populations. And as the prolongation of symptom duration, the incidence of acid-base imbalance increased significantly. Infants with persistent vomiting at the age of 3∼5 weeks after birth should be considered IHPS, and go to hospital as soon as possible in order to reduce the incidence of hypokalemia, hypochloraemia and hypercapnia, and avoid deterioration.

Educational outcome in adolescence following pyloric stenosis repair before 3 months of age: a nationwide cohort study

BACKGROUND

Immature animals exposed to anesthetics display apoptotic neurodegeneration with subsequent long-term cognitive dysfunctions. Young age at anesthetic exposure is believed to be critical, but human studies are scarce. This study investigated the association between exposure to surgery and anesthesia for pyloric stenosis (PS) before 3 months of age and subsequent educational outcome in adolescence.

METHODS

This nationwide unselected register-based follow-up study of the Danish birth cohorts 1986-1990 compared the educational outcome of all children having undergone surgery for PS before 3 months of age with a randomly selected, age-matched 5% sample of the same cohort. Primary analysis compared the average test scores at ninth grade adjusting for gender, birth weight, and parental age and education. Secondary analysis compared the proportions not attaining the test scores between the two groups.

RESULTS

The exposure group comprised 779 and the control group consisted of 14 665 individuals. Although the exposure group performed lower than the control group (average score 0.17 lower, 95% CI: 0.08-0.25), after adjusting for known confounders, no statistically significant difference (-0.04, 95% CI: -0.09 to 0.08) between the 2 groups could be demonstrated. However, we found an odds ratio (OR) for test score nonattainment-associated PS repair of 1.37 (95% CI: 1.11-1.68).

CONCLUSION

Children operated for PS before 3 months of age have educational performance tests similar to the background population at age 15-16 years after adjusting for known confounders. The higher nonattainment rate could suggest that a subgroup of PS children is developmentally disadvantaged.

Plasma lipids, genetic variants near APOA1, and the risk of infantile hypertrophic pyloric stenosis

IMPORTANCE

Infantile hypertrophic pyloric stenosis (IHPS) is a serious condition in which hypertrophy of the pyloric sphincter muscle layer leads to gastric outlet obstruction. Infantile hypertrophic pyloric stenosis shows strong familial aggregation and heritability, but knowledge about specific genetic risk variants is limited.

OBJECTIVES

To search the genome comprehensively for genetic associations with IHPS and validate findings in 3 independent sample sets.

DESIGN, SETTING, AND PARTICIPANTS

During stage 1, we used reference data from the 1000 Genomes Project for imputation into a genome-wide data set of 1001 Danish surgery-confirmed samples (cases diagnosed 1987-2008) and 2371 disease-free controls. In stage 2, the 5 most significantly associated loci were tested in independent case-control sample sets from Denmark (cases diagnosed 1983-2010), Sweden (cases diagnosed 1958-2011), and the United States (cases diagnosed 1998-2005), with a total of 1663 cases and 2315 controls.

MAIN OUTCOMES AND MEASURES

Association of genetic variation with the presence of infantile hypertrophic pyloric stenosis.

RESULTS

We found a new genome-wide significant locus for IHPS at chromosome 11q23.3. The single-nucleotide polymorphism (SNP) with the lowest P value at the locus, rs12721025 (odds ratio [OR], 1.59; 95% CI, 1.38-1.83; P = 1.9 × 10(-10)), is located 301 bases downstream of the apolipoprotein A-I (APOA1) gene and is correlated (r2 between 0.46 and 0.80) with SNPs previously found to be associated with levels of circulating cholesterol. For these SNPs, the cholesterol-lowering allele consistently was associated with increased risk of IHPS.

CONCLUSIONS AND RELEVANCE

This study identified a new genome-wide significant locus for IHPS. Characteristics of this locus suggest the possibility of an inverse relationship between levels of circulating cholesterol in neonates and IHPS risk, which warrants further investigation.

Infantile hypertrophic pyloric stenosis--genetics and syndromes

Infantile hypertrophic pyloric stenosis (IHPS) is a common condition in neonates that is characterized by an acquired narrowing of the pylorus. The aetiology of isolated IHPS is still largely unknown. Classic genetic studies have demonstrated an increased risk in families of affected infants. Several genetic studies in groups of individuals with isolated IHPS have identified chromosomal regions linked to the condition; however, these associations could usually not be confirmed in subsequent cohorts, suggesting considerable genetic heterogeneity. IHPS is associated with many clinical syndromes that have known causative mutations. Patients with syndromes associated with IHPS can be considered as having an extreme phenotype of IHPS and studying these patients will be instrumental in finding causes of isolated IHPS. Possible pathways in syndromic IHPS include: (neuro)muscular disorders; connective tissue disorders; metabolic disorders; intracellular signalling pathway disturbances; intercellular communication disturbances; ciliopathies; DNA-repair disturbances; transcription regulation disorders; MAPK-pathway disturbances; lymphatic abnormalities; and environmental factors. Future research should focus on linkage analysis and next-generation molecular techniques in well-defined families with multiple affected members. Studies will have an increased chance of success if detailed phenotyping is applied and if knowledge about the various possible causative pathways is used in evaluating results.

Bottle-feeding and the Risk of Pyloric Stenosis

OBJECTIVES

Bottle-feeding has been suggested to increase the risk of pyloric stenosis (PS). However, large population-based studies are needed. We examined the effect of bottle-feeding during the first 4 months after birth, by using detailed data about the timing of first exposure to bottle-feeding and extensive confounder information.

METHODS

We performed a large population-based cohort study based on the Danish National Birth Cohort, which provided information on infants and feeding practice. Information about surgery for PS was obtained from the Danish National Patient Register. The association between bottle-feeding and the risk of PS was evaluated by hazard ratios (HRs) estimated in a Cox regression model, adjusting for possible confounders.

RESULTS

Among 70148 singleton infants, 65 infants had surgery for PS, of which 29 were bottle-fed before PS diagnosis. The overall HR of PS for bottle-fed infants compared with not bottle-fed infants was 4.62 (95% confidence interval [CI]: 2.78-7.65). Among bottle-fed infants, risk increases were similar for infants both breast and bottle-fed (HR: 3.36 [95% CI: 1.60-7.03]), formerly breastfed (HR: 5.38 [95% CI: 2.88-10.06]), and never breastfed (HR: 6.32 [95% CI: 2.45-16.26]) (P = .76). The increased risk of PS among bottle-fed infants was observed even after 30 days since first exposure to bottle-feeding and did not vary with age at first exposure to bottle-feeding.

CONCLUSIONS

Bottle-fed infants experienced a 4.6-fold higher risk of PS compared with infants who were not bottle-fed. The result adds to the evidence supporting the advantage of exclusive breastfeeding in the first months after birth.

Pre- and perinatal risk factors for pyloric stenosis and their influence on the male predominance

Pyloric stenosis occurs with a nearly 5-fold male predominance. To what extent this is due to environmental factors is unknown. In a cohort of all children born in Denmark, 1977-2008, the authors examined the association between pre- and perinatal exposures and pyloric stenosis and investigated whether these factors modified the male predominance. Information on pre- and perinatal factors and pyloric stenosis was obtained from national registers. Poisson regression models were used to estimate rate ratios. Among 1,925,313 children, 3,174 had surgery for pyloric stenosis. The authors found pyloric stenosis to be significantly associated with male sex, age between 2 and 7 weeks, early study period, being first born, maternal smoking during pregnancy, preterm delivery, small weight for gestational age, cesarean section, and congenital malformations. Among cases, 2,595 were males and 579 were females. Lower male predominance was associated with age at diagnosis outside the peak ages, early study period, no maternal smoking during pregnancy, preterm delivery, and congenital malformations. The authors have previously found a strong familial aggregation of pyloric stenosis indicating a genetic influence. This study shows that environmental factors during and shortly after pregnancy also play a role and that several of these modify the strong male predominance.

Decline in infantile hypertrophic pyloric stenosis in Germany in 2000-2008

BACKGROUND AND OBJECTIVE

The incidence of infantile hypertrophic pyloric stenosis (IHPS) is highly variable over time and geographic regions. A decline in IHPS incidence was recently reported in Sweden, the United States, Denmark, and Scotland. In Sweden, the IHPS decline seemed to be concurrent with a declining incidence in sudden infant death syndrome (SIDS), which suggested a common cause; the latter was attributed to campaigns against the prone sleeping position. We investigated the time course of the IHPS incidence in all German federal states (N = 16) between 2000 and 2008. We examined correlations between the IHPS incidence and the SIDS incidence.

METHODS

Data were extracted from the public report of health (Gesundheitsberichterstattung des Bundes). We collected the numbers of IHPS (International Classification of Diseases, 10th Revision [ICD-10], code 40.0), SIDS (ICD-10, R95), and live births (LB; male/female) in each federal state for 2000-2008.

RESULTS

The IHPS incidence declined in Germany from 2000 (3.2086/1000 LB [range: 1.67-5.33]) to 2008 (2.0175/1000 LB [1.74-3.72]; P = .005). The recorded incidence was highly variable in different federal states and over time. The SIDS incidence also declined during the same time period (2000, median: 0.759/1000 LB [interquartile range: 0.54-1.029]; 2008, median: 0.416/1000 LB [interquartile range: 0.285-0.6485]; P = .0255). However, the SIDS regional distribution was different from that of IHPS.

CONCLUSIONS

The IHPS incidence declined by ∼38% nationwide. A parallel decline in SIDS displayed a different pattern in regional distribution; thus, a common cause was unlikely. The regional differences indicated that etiologic factors remained unresolved.

Bilious vomiting does not rule out infantile hypertrophic pyloric stenosis

OBJECTIVE

To describe the incidence of bilious vomiting in infants with infantile hypertrophic pyloric stenosis that presented to a pediatric emergency department.

METHODS

A retrospective medical record review included all infants who presented to our level 1 pediatric emergency department from January 1, 2005, through December 31, 2009, who were diagnosed intraoperatively with infantile hypertrophic pyloric stenosis. Emesis was determined to be bilious if the vomit was described as "green," "containing bile," or "bilious."

RESULTS

The authors identified 354 infants with infantile hypertrophic pyloric stenosis. The median age was 4 weeks 6 days (range = 11 days to 13 weeks). Bilious emesis was encountered in 1.4% (5/354; 95% confidence interval = 0.5% to 3.2%). The pyloric thickness measurements on ultrasound were significantly smaller in those with bilious emesis compared with those without bilious emesis (z score = 2.64; P = .014).

CONCLUSION

Bilious emesis was the presenting symptom in a small proportion of infants with infantile hypertrophic pyloric stenosis.

Developmental outcomes following major surgery: what does the literature say?

Relative to the wealth of information in the medical literature regarding developmental outcome for infants who have had cardiac surgery available, few studies specifically detail how those who have undergone major surgery grow and develop. The few published studies tend to be disease specific, making their results difficult to translate to a more general setting. As mortality for most infants who require surgery in infancy continues to decrease, the focus for researchers and clinicians should be on how these children will grow and develop. As parents realise that their infant will survive, this becomes their next major concern. The most common conditions requiring early major surgery have been reviewed in relation to data on infant developmental outcomes.

Accuracy of sonographic criteria in the decision for surgical treatment in infantile hypertrophic pyloric stenosis

INTRODUCTION

Abdominal ultrasonography has replaced barium studies in establishing the diagnosis in difficult cases of infantile hypertrophic pyloric stenosis (IHPS). The aim of this retrospective study was to establish sonographic criteria of qualification for surgical treatment in children with IHPS.

MATERIAL AND METHODS

Hundred and fifteen infants (98 boys and 17 girls) with suspected IHPS were treated between 2000 and 2009. Pyloric muscle thickness, pyloric diameter and pyloric length were measured in US scans in all patients. Results were compared with US results of 19 infants with negative diagnosis and 29 children of the reference group.

RESULTS

Diagnosis of IHPS was confirmed by US examination in 96 children (83.5%). There were 86 boys in the group with male prevalence 8.6 : 1. The remaining 19 infants (16.5%) had a negative ultrasound. The mean PL (20.89 vs. 12.73), PMT (5.41 vs. 2.24), and PD (14.1 vs. 7.42) differed significantly between patients with and without pyloric stenosis (p < 0.0001). The mean PL (12.34), PMT (2.2), and PD (7.48) in the reference group did not differ statistically from values obtained in patients with negative IHPS diagnosis and were significantly lower than in children from the IHPS group (p < 0.0001). US imaging had a sensitivity of 98%, specificity of 100%, with a positive and negative predictive value of 100% and 90% respectively.

CONCLUSIONS

This study confirmed that ultrasonography is the first choice of diagnostic method in an infant with suspected hypertrophic pyloric stenosis. In cases with an uncertain clinical diagnosis of IHPS the examination can be easily repeated.

Infantile hypertrophic pyloric stenosis: are viruses involved?

Infantile hypertrophic pyloric stenosis (IHPS) is characterized by abnormal thickening of the internal circular muscle layer. IHPS is known to be due to a combination of genetic and environmental factors, but its precise causes and pathophysiology are poorly understood. The objective of the study is to determine the prevalence of the principal viruses targeting the respiratory and digestive tracts in children with IHPS. Nasopharyngeal fluids, stools, vomit, and surgical pyloric muscle fragments and swabs were tested by cell culture, viral antigen assay and PCR. IHPS was diagnosed in 23 boys and 8 girls with a mean (±SD) age of 42 ± 15 days (range 20–88 days). There was no seasonal pattern of diagnosis. Twenty‐two children (71%) lost weight (mean 246 ± 164 g, range 30–600 g) after the onset of vomiting, and five (16.1%) were dehydrated. Seven (22.6%) infants had been exposed to an infectious contact within 15 days before admission, and one on the day of admission (3.2%). Ear, nose and throat samples and pyloric muscle specimens were negative for all the viruses tested. An adenovirus type 3 was recovered from one stool sample, and RT‐PCR was positive for an enterovirus on one vomit sample. This study suggests that the principal viruses targeting the respiratory and digestive tracts are not responsible for IHPS. J. Med. Virol. 82:2087–2091, 2010. © 2010 Wiley‐Liss, Inc.

Early developmental outcome of infants with infantile hypertrophic pyloric stenosis

PURPOSE

The study aimed to compare the developmental outcome of infants with infantile hypertrophic pyloric stenosis (IHPS) who underwent pyloromyotomy with healthy control infants in New South Wales (NSW), Australia.

METHODS

Infants diagnosed with IHPS requiring surgical intervention were enrolled prospectively between August 1, 2006, and July 31, 2008. Healthy control infants were enrolled in the same period. The children underwent a developmental assessment at 1 year of age (corrected) using the Bayley Scales of Infant and Toddler Development (Version III).

RESULTS

Of 52 infants with IHPS who were enrolled, 43 had developmental assessments. Most (90.6%) were term infants (>36 weeks gestation) with a median birth weight of 3237.8 g. Two infants (8%) had an associated birth defect, and survival was 100%. Developmental assessments were also performed on 211 control infants. Infants with IHPS scored significantly lower on the cognitive, receptive language, fine motor, and gross motor subscales compared to the control infants.

CONCLUSIONS

This unique study found lower than expected developmental scores for infants after surgery for IHPS than for healthy control infants. These findings raise concerns over the potential impact of IHPS and its surgical treatment. Further studies, including continuing developmental review to determine whether these differences persist and their functional importance, should be performed.