The changing clinical presentation of hypertrophic pyloric stenosis: the experience of a large, tertiary care pediatric hospital

Effectiveness of two-dimensional shear-wave sonoelastography in the diagnosis and follow-up of infantile hypertrophic pyloric stenosis

INTRODUCTION

We sought to determine the effectiveness and utility of two-dimensional shear-wave sonoelastography (2D-SW-SE) in the diagnosis and postoperative follow-up of infantile hypertrophic pyloric stenosis (IHPS).

MATERIALS AND METHODS

Twenty-three infants were included in the study, 13 in the IHPS group and 10 in the control group (CG). Preoperative B-mode ultrasonography measurements (longitudinal length and single-wall thickness of the pylorus) and 2D-SW-SE measurements (pylorus tissue stiffness and shear-wave propagation speed) were compared between the groups. The infants with IHPS then underwent Ramstedt pyloromyotomy and were invited for follow-ups on the tenth day and the first, third, and sixth months postoperatively. Measurements taken at the follow-ups were compared with the preoperative values.

RESULTS

No differences were found between the groups regarding age, gender, body weight, or week of birth. The pyloric lengths in the IHPS group were longer than in the CG (p < 0.001), and the single-wall thicknesses were thicker (p < 0.001). The pylorus in the IHPS group was four times stiffer than in the CG (27.4 kPa versus 7.66 kPa), and the shear-wave propagation speed in the tissue was higher (1.34 m/s versus 2.69 m/s; p < 0.001). Both values decreased over time in the IHPS group and were normal by the third postoperative month.

CONCLUSIONS

2D-SW-SE can be used as an assistive imaging tool alongside B-mode ultrasound for diagnosing IHPS. It can also be used to identify inadequate surgery by detecting whether the pyloric tissue has softened at follow-up.

Vomiting, Pyloric Mass, and Point-of-Care Ultrasound: Diagnostic Test Accuracy for Hypertrophic Pyloric Stenosis-A Meta-Analysis

BACKGROUND

Hypertrophic pyloric stenosis is a common cause of nonbilious vomiting in infants younger than 6 months. Its history, physical examination, and point-of-care ultrasound (POCUS) have not been compared for their diagnostic test accuracy.

OBJECTIVE

The aim of this systematic review was to quantify and compare the diagnostic test accuracy of a history of vomiting, a pyloric mass on palpation, and POCUS.

METHODS

We performed three searches of the literature from 1977 to March 2022. We evaluated bias using the QUADAS-2 (Quality Assessment Tool for Diagnostic Accuracy-2) tool. We performed a bivariate analysis.

RESULTS

From 5369 citations, we identified 14 studies meeting our inclusion criteria. We quantified three diagnostic elements: POCUS, a pyloric mass on palpation, and vomiting. We identified five studies that analyzed POCUS, which included 329 patients. POCUS had a sensitivity of 97.7% (95% confidence interval (CI) 93.1-99.3%) and a specificity of 94.1% (95% CI 88.7-97.1%) for detecting pyloric stenosis. We identified six studies that analyzed the presence of a pyloric mass, which included 628 patients. The palpation of a pyloric mass had a sensitivity of 73.5% (95% CI 62.6-82.1%) and a specificity of 97.5% (95% CI 93.8-99.0%). We identified four studies that analyzed vomiting, which included 355 patients. Vomiting had a sensitivity of 91.3% (95% CI 82.1-96.0) and a specificity of 60.8% (95% CI 8.5-96.3). Both POCUS and palpation of a pyloric mass had a high positive likelihood ratio (LR+: 17 and 33, respectively). The LR+ for vomiting was 5.0.

CONCLUSIONS

Both POCUS and palpable mass had high specificity and positive LR, whereas vomiting provided the lowest diagnostic test measures.

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.

Diagnostic accuracy of palpation and ultrasonography for diagnosing infantile hypertrophic pyloric stenosis: a systematic review and meta-analysis

Objective:

Although infantile hypertrophic pyloric stenosis (IHPS) is a well-known disease, there is no systematic review regarding the optimal diagnostic strategy. We conducted a systematic review and meta-analysis to obtain diagnostic accuracy of all methods to diagnose IHPS.

Methods:

According to the Preferred Reported Items for Systematic Reviews and Meta-Analysis guidelines, we searched MEDLINE and Embase to identify studies reporting sensitivity and specificity of all methods used to diagnose IHPS. Inclusion criteria were infants with suspicion of/or diagnosed with IHPS who underwent pyloromyotomy or had clinical follow-up. A random-effects model was used to obtain pooled estimates of sensitivity, specificity and area under the receiver operating characteristic curve.

Results:

After screening 5364 studies, we included 43 studies with in total 6085 infants (n = 4241 IHPS; n = 1844 controls). The diagnostic sensitivity of palpation ranged from 10.0 to 93.4% and decreased over time. Different parameters for ultrasonography were found. Most used parameters were pyloric muscle thickness (PMT) ≥ 3 mm (pooled sensitivity 97.6% and specificity 98.8%), PMT ≥ 4 mm (pooled sensitivity 94.0% and specificity 98.0%) or a combination of PMT ≥ 4 mm and/or pyloric canal length ≥16 mm (pooled sensitivity 94.0% and specificity 91.7%). The AUC showed high diagnostic accuracy (0.997, 0.966 and 0.981 respectively), but large heterogeneity exists. Due to the large differences in cut-off values no meta-analysis could be conducted for pyloric canal length and pyloric diameter.

Conclusion:

Palpation has limited sensitivity in diagnosing IHPS. We showed that ultrasonography has highest diagnostic accuracy to diagnose IHPS and we advise to use PMT ≥ 3 mm as cut-off.

Advances in knowledge:

This is the first systematic review and meta-analysis on diagnosing IHPS, which summarizes the available literature and may be used as a guideline.

Evidence-Based Diagnostic Test Accuracy of History, Physical Examination, and Imaging for Intussusception: A Systematic Review and Meta-analysis

INTRODUCTION

Intussusception is the most common cause of pediatric small bowel obstruction. Timely and accurate diagnosis may reduce the risk of bowel ischemia. We quantified the diagnostic test accuracy of history, physical examination, abdominal radiographs, and point-of-care ultrasound.

METHOD

We conducted a systematic review for diagnostic test accuracy of history, physical examination, and imaging concerning for intussusception. Our literature search was completed in June 2019. Databases included Medline via Ovid, Embase, Scopus, and Wiley Cochrane Library. We conducted a second review of the literature up to June 2019 for any additional studies. Inclusion criteria were younger than 18 years and presenting to the emergency department for abdominal complaints, consistent with intussusception. We performed data analysis using mada, version 0.5.8. We conducted univariate and bivariate analysis (random effects model) with DerSimonian-Laird and Reitsma model, respectively. QUADAS-2 was used for bias assessment.

RESULTS

The literature search identified 2639 articles, of which 13 primary studies met our inclusion criteria. Abdominal pain, vomiting, and bloody stools had positive likelihood ratios LR(+) between 1 and 2, whereas the negative likelihood ratio, LR(-), ranged between 0.4 and 0.8. Abnormal abdominal radiograph had LR(+) of 2.5 and LR(-) of 0.20, whereas its diagnostic odds ratio was 13. Lastly, point-of-care ultrasound had LR(+) of 19.7 and LR(-) of 0.10. The diagnostic odds ratio was 213.

CONCLUSIONS

History and physical examination had low diagnostic test accuracy. Abdominal radiographs had low diagnostic test accuracy, despite moderate discriminatory characteristics. Point-of-care ultrasound had the highest diagnostic test accuracy to rule in or rule out intussusception.

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.

Neonatal Bowel Disorders: Practical Imaging Algorithm for Trainees and General Radiologists

OBJECTIVE

Neonatal bowel disorders require prompt and accurate diagnosis to avoid potential morbidity and mortality. Symptoms such as feeding intolerance, emesis, or failure to pass meconium may prompt a radiologic evaluation.

CONCLUSION

We discuss the most common neonatal bowel disorders and present a practical imaging algorithm for trainees and general radiologists.

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.

Immediate Emergency Department Diagnosis of Pyloric Stenosis with Point-of-care Ultrasound

A 15-day-old male who was born at term presented with non-bilious projectile vomiting. He was nontoxic and his abdomen was benign without masses. Point-of-care ultrasound (POCUS) showed hypertrophic pyloric stenosis (HPS). Typical findings include target sign; pyloric muscle thickness greater than three millimeters (mm); channel length greater than 15–18 mm; and lack of gastric emptying. The patient was admitted; consultative ultrasound (US) was negative, but repeated 48 hours later for persistent vomiting. This second US was interpreted as HPS, which was confirmed surgically. Pyloromyotomy was successful. Few reports describe POCUS by general emergency physicians to diagnose HPS. Here, we emphasize the value in repeat US for patients with persistent symptoms.

Pediatric Abdominal Pain: An Emergency Medicine Perspective

Abdominal pain is a common complaint that leads to pediatric patients seeking emergency care. The emergency care provider has the arduous task of determining which child likely has a benign cause and not missing the devastating condition that needs emergent attention. This article reviews common benign causes of abdominal pain as well as some of the cannot-miss emergent causes.

Does metabolic alkalosis influence cerebral oxygenation in infantile hypertrophic pyloric stenosis?

BACKGROUND

This pilot study focuses on regional tissue oxygenation (rSO₂) in patients with infantile hypertrophic pyloric stenosis in a perioperative setting. To investigate the influence of enhanced metabolic alkalosis (MA) on cerebral (c-rSO₂) and renal (r-rSO₂) tissue oxygenation, two-site near-infrared spectroscopy (NIRS) technology was applied.

MATERIALS AND METHODS

Perioperative c-rSO₂, r-rSO₂, capillary blood gases, and electrolytes from 12 infants were retrospectively compared before and after correction of MA at admission (T1), before surgery (T2), and after surgery (T3).

RESULTS

Correction of MA was associated with an alteration of cerebral oxygenation without affecting renal oxygenation. When compared to T1, 5-min mean (± standard deviation) c-rSO₂ increased after correction of MA at T2 (72.74 ± 4.60% versus 77.89 ± 5.84%; P = 0.058), reaching significance at T3 (80.79 ± 5.29%; P = 0.003). Furthermore, relative 30-min c-rSO₂ values at first 3 h of metabolic compensation were significantly lowered compared with postsurgical states at 16 and 24 h. Cerebral oxygenation was positively correlated with levels of sodium (r = 0.37; P = 0.03) and inversely correlated with levels of bicarbonate (r = -0.34; P = 0.05) and base excess (r = -0.36; P = 0.04). Analysis of preoperative and postoperative cerebral and renal hypoxic burden yielded no differences. However, a negative correlation (r = -0.40; P = 0.03) regarding hematocrite and mean r-rSO₂, indirectly indicative of an increased renal blood flow under hemodilution, was obtained.

CONCLUSIONS

NIRS seems suitable for the detection of a transiently impaired cerebral oxygenation under state of pronounced MA in infants with infantile hypertrophic pyloric stenosis. Correction of MA led to normalization of c-rSO₂. NIRS technology constitutes a promising tool for optimizing perioperative management, especially in the context of a possible diminished neurodevelopmental outcome after pyloromyotomy.

Pediatric emergency medicine point-of-care ultrasound: summary of the evidence

The utility of point-of-care ultrasound is well supported by the medical literature. Consequently, pediatric emergency medicine providers have embraced this technology in everyday practice. Recently, the American Academy of Pediatrics published a policy statement endorsing the use of point-of-care ultrasound by pediatric emergency medicine providers.  To date, there is no standard guideline for the practice of point-of-care ultrasound for this specialty. This document serves as an initial step in the detailed "how to" and description of individual point-of-care ultrasound examinations.  Pediatric emergency medicine providers should refer to this paper as reference for published research, objectives for learners, and standardized reporting guidelines.

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.

Recent changes in the features of hypertrophic pyloric stenosis

BACKGROUND

Hypertrophic pyloric stenosis (HPS) is a rare cause of non-bilious vomiting in young infants; the condition requires surgical management. Diagnosis is based on clinical, laboratory, and radiological findings. In the present study, we evaluate recent changes in the features of HPS.

METHOD

We retrospectively reviewed the demographic, clinical, and laboratory data on 56 HPS patients who underwent pyloromyotomy between 1996 and 2015. Patients were divided into two groups according to date of operation (group 1, 1996-2006; group 2, 2007-2015).

RESULTS

Group 1 consisted of 30 patients and group 2, 26. The age at diagnosis was longer in group 2 (43.3 ± 13.1 days) than group 1 (37.4 ± 17.7 days). All diagnoses were confirmed on ultrasonography. Pyloromyotomy was performed on all 56 patients (48 boys, 8 girls). Significant between-group differences were evident in terms of age at onset of vomiting; rate of dehydration; development of palpable olive-shaped abdominal mass; serum urea and creatinine; acid-base status; and air distribution pattern on abdominal radiography (all P < 0.05).

CONCLUSION

The frequency of olive-shaped abdominal mass evident on physical examination decreased significantly over time, and was lower than published values. Early diagnosis triggers timely support and surgical intervention, and may thus prevent development of the classical clinical and laboratory findings of late-stage HPS. The remarkable recent advances in ultrasonography and techniques allow HPS to be diagnosed earlier than formerly.

Is There a Relation Between Pyloric Muscle Thickness and Clinical and Laboratory Data in Infants with Hypertrophic Pyloric Stenosis?

Literature about the association between clinical and laboratory presentation and pyloric muscle thickness in infants with pyloric stenosis is lacking. The objective of this study is to examine the effect of pyloric muscle thickness on clinical and laboratory presentation in infants with pyloric stenosis. Thirty infants with hypertrophic pyloric stenosis presented at the Maternity and Children Hospital, Al-Madinah, Saudi Arabia, were included in this study analysis. Clinical and laboratory data of these infants were recorded. Statistical tests and univariate linear regression analyses were used as appropriate. P value was considered significant at a level ≤0.05. The mean age of the studied infant was 5.1 ± 2.6 weeks and mean weight was 3.4 ± 0.7 kg. Most of these infants were full-term (93.3 %), some presented to the hospital dehydrated (80 %), and some were lethargic (56.7 %). The mean pyloric muscle thickness among these infants showed statistically significant difference with regard to the studied clinical and laboratory data. A linear regression analyses also showed positive association between increasing pyloric muscle thickness and almost all studied clinical and laboratory data, with statistically significant difference observed for hyponatremia, hypochloremia, and high bicarbonates. The findings suggest that pyloric muscle thickness is a significant factor that determines the severity of clinical and laboratory presentation in infants with pyloric stenosis.

Evaluation of hypertrophic pyloric stenosis by pediatric emergency physician sonography

OBJECTIVES

The objective was to evaluate the accuracy of pediatric emergency physician (EP) sonography for infants with suspected hypertrophic pyloric stenosis (HPS).

METHODS

This was a prospective observational pilot study in an urban academic pediatric emergency department (PED). Patients were selected if the treating physician ordered an ultrasound (US) in the department of radiology for the evaluation of suspected HPS.

RESULTS

Sixty-seven patients were enrolled from August 2009 through April 2012. When identifying the pylorus, pediatric EPs correctly identified all 10 positive cases, with a sensitivity of 100% (95% confidence interval [CI] = 62% to 100%) and specificity of 100% (95% CI = 92% to 100%). There was no statistical difference between the measurements obtained by pediatric EPs and radiology staff for pyloric muscle width or length (p = 0.5 and p = 0.79, respectively).

CONCLUSIONS

Trained pediatric EPs can accurately assess the pylorus with US in the evaluation of HPS with good specificity.

Citrullinemia type I and hypertrophic pyloric stenosis in a 1-month old male infant

Citrullinemia type I (CTLN1) is an inherited urea cycle disorder, now included in most newborn screening panels in the US and Europe. Due to argininosuccinate synthetase deficiency, CTLN1 can lead to recurrent hyperammonemic crisis that may result in permanent neurologic sequelae. Vomiting in patients with urea cycle disorders may either be the result or cause of acute hyperammonemia, particularly if due to an illness that leads to catabolism. Therefore, age-appropriate common etiologies of vomiting must be considered when evaluating these patients. We present a 1-month old male infant with CTLN1 who had a 1-week history of vomiting and was discovered to have hypertrophic pyloric stenosis. This is the first documented case of an infant with CTLN1 who was later diagnosed with hypertrophic pyloric stenosis, and only the second case of concomitant disease.

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.