Evaluation of ultrasonographic parameters in the diagnosis of pyloric stenosis relative to patient age and size

Point-of-care abdominal ultrasound in pediatric and neonatal intensive care units

A spectrum of critical abdominal pathological conditions that might occur in neonates and children warrants real-time point-of-care abdominal ultrasound (abdominal POCUS) assessment. Abdominal radiographs have limited value with low sensitivity and specificity in many cases and have no value in assessing abdominal organ perfusion and microcirculation (Rehan et al. in Clin Pediatr (Phila) 38(11):637-643, 1999). The advantages of abdominal POCUS include that it is non-invasive, easily available, can provide information in real-time, and can guide therapeutic intervention (such as paracentesis and urinary bladder catheterization), making it a crucial tool for use in pediatric and neonatal abdominal emergencies (Martínez Biarge et al. in J Perinat Med 32(2):190-194, 2004) and (Alexander et al. in Arch Dis Child Fetal Neonatal Ed 106(1):F96-103, 2021).  Conclusion: Abdominal POCUS is a dynamic assessment with many ultrasound markers of gut injury by two dimensions (2-D) and color Doppler (CD) compared to the abdominal X-ray; the current evidence supports the superiority of abdominal POCUS over an abdominal X-ray in emergency situations. However, it should still be considered an adjunct rather than replacing abdominal X-rays due to its limitations and operator constraints (Alexander et al. in Arch Dis Child Fetal Neonatal Ed 106(1):F96-103, 2021). What is Known: • Ultrasound is an important modality for the assessment of abdominal pathologies. What is New: • The evidence supports the superiority of abdominal POCUS over an abdominal X-ray in emergency abdominal situations in the neonatal and pediatric intensive care units.

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.

Stratifying features for diagnosing hypertrophic stenosis on ultrasound: a diagnostic accuracy study

Background

Our aims were to determine if the diagnostic threshold for diagnosing hypertrophic pyloric stenosis (HPS) on ultrasound scan (USS) should be adjusted based on birth weight (BW), current weight (CW), gestational age (GA), chronological age (CA) or corrected gestational age (CGA).

Methods

All patients who underwent either an USS and pyloromyotomy (Group 1) or an USS for possible HPS (Group 2) at our tertiary centre between July 2013 and June 2019 were identified. Ideal threshold values are identified by measuring Youden's Index (J = sensitivity + specificity – 1; higher is better). Mean maximum Youden's Index for stratified results was compared to that for combined results.

Results

Two hundred and eighty‐four patients were included (142 patients in both Group 1 and Group 2). Combined maximum Youden's Index for all patients was 0.92 for pyloric canal thickness (PMT) and 0.87 for pyloric canal length (PCL). Mean maximum Youden's Index was higher when patients were stratified by GA, CGA, BW or CW, and equivalent for CA. For pyloric canal length (PCL), mean maximum Youden's Index was lower for all variables when stratified compared to combined. There was no visual trend observed in the diagnostic thresholds between groups.

Conclusion

Stratifying USS PMT diagnostic thresholds values based on age and weight is statistically more accurate than a single threshold in diagnosing HPS. However, the lack of visual correlation indicates a larger dataset is required to validate these results.

Evaluating the validity of ultrasound in diagnosing hypertrophic pyloric stenosis: a cross-sectional diagnostic accuracy study

BACKGROUND

Our aims were to evaluate the ultrasound scan (USS) criteria in diagnosing hypertrophic pyloric stenosis (HPS), determine the best diagnostic threshold values for pyloric muscle thickness (PMT) and pyloric canal length (PCL), and assess the accuracy of flow through the pylorus.

METHODS

All patients who underwent pyloromyotomy at our tertiary paediatric surgery centre between July 2013 and June 2019 were identified (Group 1). All patients undergoing an USS to investigate for a possible HPS and did not undergo pyloromyotomy were also identified (Group 2). Accuracy was determined by Youden's Index (J) with the highest J determining the ideal cut-off value.

RESULTS

Two hundred and eighty-four patients (142 patients in each group) were included in the analysis. Using only the last USS before surgery, PMT provided an area under the curve (AUC) of 0.987 (n = 275), and PCL an AUC of 0.977 (n = 267). Ideal threshold values were 3.0 mm for PMT (J = 0.92), and 14.5 mm for PCL (J = 0.87). Combining PMT ≥3.0 mm with a PCL ≥14.5 mm resulted in a sensitivity of 95% and specificity of 99% (J = 0.94). The absence of flow through the pylorus on dynamic USS provided a sensitivity of 99% and specificity of 91% (J = 0.91; n = 277).

CONCLUSION

Combining threshold values of 3.0 mm for PMT and 14.5 mm PCL provides the highest accuracy for diagnosing pyloric stenosis on an ultrasound scan. These combined values were more accurate than observing for the absence of flow through the pylorus.

Hypertrophic pyloric stenosis following repair of oesophageal atresia and tracheo-oesophageal fistula in a neonate

Development of hypertrophic pyloric stenosis (HPS) after a few weeks of repair of an oesophageal atresia (OA) and tracheo-oesophageal fistula (TOF) is a rare condition in early infancy. Although vomiting or feeding intolerance in operated cases of OA+TOF are attributed to oesophageal stricture, gastro-oesophageal reflux and oesophageal dysmotility, it may also be caused by HPS. Herein, we report a newborn infant who had OA and TOF operation on day 2 of life and diagnosed to have HPS at 15th day of age. Even though it is a rare anomaly, HPS should be kept on mind in the presence of persistent vomiting following repair of OA.

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.

Infantile hypertrophic pyloric stenosis - Our experience and challenges in a developing country

BACKGROUND

This study aims to evaluate the experience and challenges in managing patients with infantile hypertrophic pyloric stenosis (IHPS).

PATIENTS AND METHODS

From January 2007 to December 2015, data from patients with IHPS were retrospectively acquired and analyzed using SPSS version 15. Pearson correlation used to assess linear relationships and Student t-test to compare means. P < 0.05 was taken as statistically significant. Results were expressed as percentages, means ± standard deviation and illustrated in tables and graphs.

RESULTS

Twenty-six cases were managed with the mean age at diagnosis of 49.16 ± 21.4 days. Mean birth weight was 3.7 kg and mean weight at presentation was 3.3 kg. Firstborn was affected in 29%; 91% were term deliveries; 9% were post-term; none was preterm; and 36% were exclusively breastfed. Mean duration of symptoms was 25.6 ± 18.9 days. Hyponatraemia was seen in 36%, hypokalaemia 37.5%, alkalosis 35% and hypochloraemia 62%. Mean pyloric tumour length was 22.85 ± 6.56 mm and pyloric wall thickness 5.51 ± 1.36 mm. There was a significant correlation between duration of symptoms and serum potassium level (R = -0.6326, P = 0.002). Mean symptom duration in patients with hypokalaemia was 39.88 ± 23.41 days and without hypokalaemia 17.15 ± 9.78 days (P = 0.006). Mean hospital stay was 9.45 ± 3.27 days. Four patients developed four complications and three patients died (11.5%). Mean age at presentation for pre-operative mortalities was 84 ± 39 days and 46 ± 17.98 days for others (P = 0.015).

CONCLUSIONS

IHPS presents late in our environment and occurs mainly in term males. There is a significant positive relationship between duration of symptoms and serum potassium level and the mean duration of symptoms was significantly longer in those with hypokalaemia. Pre-operative mortality was significantly associated with longer duration of symptoms.

Consideration of pyloric stenosis as a cause of feeding dysfunction in children with cyanotic heart disease

Feeding difficulty has been reported at a higher incidence in infants with cyanotic heart disease and single ventricle physiology necessitating specialized feeding strategies. However, structural causes of feed intolerance in this subset of patients should not be ignored. This case series highlights three recent cases of pyloric stenosis in infants with left-sided obstructive lesions at our institution. In all three cases, the initial presumed diagnosis was feeding intolerance related to heart disease, and there was significant clinical improvement following identification and correction of pyloric stenosis.

Epidemiological and clinical characteristics of 304 patients with infantile hypertrophic pyloric stenosis in Anhui Province of East China, 2012-2015

OBJECTIVE

To analyze the clinical and epidemiological features of patients with infantile hypertrophic pyloric stenosis (IHPS) so as to provide scientific evidence for diagnosis and prevention of IHPS.

METHODS

We performed a retrospective study of infants with IHPS diagnosed from 2012 to 2015 at Anhui Provincial Children's Hospital. Demographic characteristics and clinical data were collected.

RESULTS

Three hundred four patients (264 males and 40 females) were studied, of which 94.7% were full term and 75.7% were bottle fed or mixed fed; 16.8% of the patients had other congenital malformations in combination with IHPS. The proportion of IHPS cases with hyponatremia, hypokalemia, and hypochloremia was 18.4%, 12.5%, and 53.9%. A negative correlation was found between duration of disease and serum electrolytes. The mean pyloric muscle thickness, pyloric length, and diameter were 4.8 ± 0.7 mm, 19.4 ± 2.5 mm, and 13.3 ± 1.8 mm, respectively. There were significant differences in muscle thickness, pyloric length, and diameter between short (≤14 d) and long (>14 d) durations of disease. All patients underwent pyloromyotomy, and postoperative recovery was good.

CONCLUSIONS

IHPS occurs mainly in male, full-term, bottle-fed or mixed-fed infants. Patients with long duration of disease were more likely to develop electrolyte disorder and thicker muscle layer. More attention should be paid to early discovery and diagnosis, which will help to improve the curative effect and prognosis of IHPS.

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.

Single-site umbilical laparoscopic pyloromyotomy in neonates less than 21-day old

PURPOSE

Single-site umbilical laparoscopic pyloromyotomy for hypertrophic pyloric stenosis in neonates <3-week old has rarely been reported in the literature. This article reports our initial experience with this procedure.

METHODS

Overall, 13 cases of hypertrophic pyloric stenosis occurred in neonates <3-week old from January 2010 to April 2013 in our hospital. All neonates were treated by a single-site laparoscopic procedure. A 5-mm trocar and endoscope were introduced through an incision in the center of the umbilicus, and two 3-mm working instruments were inserted directly into the abdomen via separate lateral fascial stab incisions in the umbilical fold, and a single-site umbilical laparoscopic pyloromyotomy was then performed.

RESULTS

The procedure was performed in 13 infants (12 male) with mean age of 17.3 days. The average length of the operation was 26 min. The mean postoperative hospital stay was 4.5 days. All patients were discharged home on full feeds. Follow-up examinations were scheduled 2 to 6 weeks after discharge, and no postoperative complications were noted in any of the patients.

CONCLUSION

These cases had shorter and thinner pylori than their older counterparts. However, the laparoscopic procedure was safe and feasible, with good postoperative results and excellent cosmesis. Surgeons should have a firm foundation of advanced minimal access surgical skills prior to attempting the procedure.

Hypertrophic pyloric stenosis in premature infants: evaluation of sonographic criteria and short-term outcomes

PURPOSE

To examine the sonographic measurements of pyloric muscle and pyloric thickness in premature infants with hypertrophic pyloric stenosis (HPS) and to correlate these measurements with patients variables. We aimed also to evaluate the clinical features and short-term outcome of HPS in premature compared to term infants.

METHODS

The medical notes and the pyloric ultrasounds of all premature infants (<37 weeks) admitted to the Neonatal Surgical Unit with HPS over a 20-year period (1990-2010) were retrospectively reviewed. Sonographic measurements of the pyloric length, muscle thickness and the pyloric ratio (muscle thickness divided by pyloric diameter) were correlated to weight at presentation, duration of symptoms and corrected gestational age. Multiple regression and correlation analysis was carried out.

RESULTS

Seventy-five preterm infants were identified (51M:24F). Median gestational age was 34 weeks. Median weight at presentation was 2.74 kg. Forty-two had an ultrasound (US) before surgery, 37 measurements were analysed. Pyloric length, muscle thickness and pyloric ratio were not affected by weight at presentation (p = 0.67, p = 0.122, p = 0.849), corrected gestational age (CGA) (p = 0.921, p = 0.678, p = 0.076), or duration of symptoms (p = 0.827, p = 0.268, p = 0.281). Mean length of stay was 6 days and overall complication rate was 27 %, both higher than reported in term infants (p < 0.001).

CONCLUSIONS

Premature infants with HPS have a higher female preponderance than expected. Ultrasound measurements in premature infants with HPS are not affected by weight, corrected gestational age or duration of symptoms. In addition, they have a longer hospital stay and increased complication rate compared to term infants.