Infantile Hypertrophic Pyloric Stenosis Patients Research Articles

Utility of Pyloric Length Measurement for Detecting Severe Metabolic Alkalosis in Infants with Hypertrophic Pyloric Stenosis.

Infantile hypertrophic pyloric stenosis (IHPS) is a common gastrointestinal disease in neonates and hypochloremia metabolic alkalosis is a typical laboratory finding in affected patients. This study aimed to analyze the clinical characteristics of infants with IHPS and evaluate the association of clinical and laboratory parameters with ultrasonographic findings. Infants diagnosed with IHPS between January 2017 and July 2022 were retrospectively evaluated. A total of 67 patients were included in the study. The mean age at diagnosis was 40.5±19.59 days, and the mean symptom duration was 11.97±9.91 days. The mean pyloric muscle thickness and pyloric canal length were 4.87±1.05 mm and 19.6±3.46 mm, respectively. Hyponatremia and metabolic alkalosis were observed in five (7.5%) and 36 (53.7%) patients, respectively. Serum sodium (p=0.011), potassium (p=0.023), and chloride levels (p=0.015) were significantly lower in patients with high bicarbonate levels (≥30 mmol/L). Furthermore, pyloric canal length was significantly higher in patients with high bicarbonate levels (p=0.015). To assess metabolic alkalosis in IHPS patients, the area under the receiver operating characteristic curve of pyloric canal length was 0.910 and the optimal cutoff value of the pyloric canal length was 23.5 mm. We found a close association between laboratory and ultrasonographic findings of IHPS. Clinicians should give special consideration to patients with pyloric lengths exceeding 23.5 mm and appropriate fluid rehydration should be given to these patients.

Ultrasonography along with Clinical Finding is enough for the Diagnosis of Infantile Hypertrophic Pyloric Stenosis

Introduction: Infantile hypertrophic pyloric stenosis (IHPS) is characterized by hypertrophy of the pyloric muscular propria, predominantly involving the circular layer and subsequent narrowing of the pyloric outlet. Aim of the Study: To see the ultrasonographic diagnosis of infantile hypertrophic pyloric stenosis. Material & Methods: This retrospective study was conducted in Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh during the period conducted from February 1997 to October 1998 in a period of 21 months. The data were collected for all 31 patients. Following, collection of all the required data, these were checked and tabulated into the computer using the SPSS/PC software 23. Results: During the study period February 1997 to October 1998 total surgical admission was 4006 and infantile hypertrophic pyloric stenosis patients (IHPS) were 31. So IHPS represented .77% of the total surgical admission during the study period in DSH. Correlation of clinical and ultra-sonogram findings with operative finding, clinical findings true +ve 20(64.52%), true –ve 2(6.45%), false +ve 1(3.23), false –ve 8(25.81) and ultra-sonogram observation true +ve 27(87.10%), true –ve 2(6.45%), false +ve 2(6.45%), false –ve 2(6.45%) and then finally operation needed IHPS ware 29(93.35%) also others than IHPS 2(6.45%). Correlation of pattern of sensitivity and specificity in clinical findings 93.1% and 50%, ultra-sonogram findings 71.43% and 66.67%. Conclusion: In conclusion, we would like to advise that infantile hypertrophic pyloric stenosis is the most common cause of non-bilious projectile vomiting in an infant. The diagnosis being mode primarily by non-bilious projectile vomiting in a neonate, which usually starts 2-4 weeks after delivery and ultrasonography can confirm the diagnosis.

Ultrasound and Infantile Pyloric Stenosis (IHPS) early Detection Better Patients

The role of ultrasound in the diagnosis of Infantile Hypertrophic Pyloric Stenosis (IHPS) can not be over emphasized. The easy availability of this reliable imaging modality may contribute to prompter diagnosis and early treatment. The author wishes to present comparison of two series, of 52 patients each, conducted in the same department, but five years apart. Spread over more than a decade our experience with IHPS patients has undergone dramatic changes, especially the diagnostic part of it. Salient features of the two studies will be highlighted. In addition the study will examine whether the easy access to ultrasound has affected the care of infants with pyloric stenosis.

Infantile Hypertrophic Pyloric Stenosis Surgery versus Nutritional Therapy

Objective: to compare the outcomes of surgery versus nutritional therapy in the management of infantile hypertrophic pyloric stenosis (IHPS). Methods: Thirty-eight IHPS patients were enrolled in the study and subdivided into surgical (22 patients) and nutritional groups (16 patients). Surgery involved extramucosal pyloromyotomy, while nutritional therapy consisted of small and frequent meals only. Patients were monitored both clinically and with ultrasound. A long-term follow-up 13-19 years after treatment was carried out to investigate gastric emptying function. Patients were assessed by ultrasound to evaluate gastric volume and emptying time. Results: All 22 surgical patients were cured. One patient from the nutritional group has withdrawn from the study. Nutritional therapy failed in 4/15 patients, who underwent surgery within 48 hours. It was successful in the remaining 11 patients. Pyloric ultrasound parameters returned to normal within 3–4 months in both groups of patients. At long-term follow-up of the gastric emptying time was normal in both groups, while a statistically significant increase of antral volume was observed in the surgery group. Conclusions: Nutritional treatment seemed a viable option in IHPS. Clinical results looked very encouraging even if treatment adoption failed in about 25% of cases.

Incidence and concurrent laparoscopic repair of hypertrophic pyloric stenosis and patent processus vaginalis.

Incidence and concurrent laparoscopic repair of hypertrophic pyloric stenosis and patent processus vaginalis.

Predictive factors of negative outcome in initial atropine therapy for infantile hypertrophic pyloric stenosis

The predictive factors of negative outcome in initial i.v. atropine (IA) therapy of infantile hypertrophic pyloric stenosis (IHPS) are unknown. Conservative therapy for IHPS is useful for infants because it does not have the risk of surgical and anesthetic stress, but some cases of atropine therapy result in failure. This study clarified the predictive markers of negative outcome in initial atropine therapy for IHPS. Seventy-six patients with IHPS admitted from 1998 to 2011 were included in this study. The predictive risk factors of negative outcome in initial atropine therapy for IHPS were evaluated. Thirty-one patients initially underwent non-operative therapy for IHPS during the study period. Of the 31 patients, 18 (58%) ceased projectile vomiting (PV) with IA and subsequent oral atropine. Univariate analysis showed that lack of bodyweight gain before treatment, elevated urine potassium at admission, and PV occurring ≥5 times (PV ≥5) in total for 3 days from IA initiation were predictive risk factors for negative outcome in IHPS. Multivariate analysis identified only PV ≥5 in total for 3 days after IA initiation as independently associated with failure of atropine for IHPS. PV ≥5 in total for 3 days after IA initiation is a potential indicator of negative outcome of IA in IHPS patients. The present results provide valuable information for determining whether early surgical intervention for IHPS or initial atropine therapy is the best option.

RET Genomic Variants in Infantile Hypertrophic Pyloric Stenosis

The recent publication on RET genomic variants in infantile hypertrophic pyloric stenosis (IHPS) is very interesting.[1] Serra et al concluded that “RET variants are present in IHPS patients yet show no significant statistical association with the IHPS phenotype, suggesting at best an adjuvant role for RET in IHPS.[1]” As noted in this report, the conclusion is still too early. The investigation in the few subjects without control group cannot imply the risk. In addition, other genetic factors are not completely investigated. Indeed, there are some previous publications on other factors and most are not conclusive. The good example is the study on motilin[2] and promoter NOS1 (nitric oxide synthase 1).[3] Finally, no statistical association might imply no role rather than a role.

The Role of Ret Genomic Variants in Infantile Hypertrophic Pyloric Stenosis

Infantile hypertrophic pyloric stenosis (IHPS) is a common childhood pathology affecting approximately 1-5 children pro 1000 newborns, with a genetic background as suggested by the familial occurrence. RET is a candidate gene for IHPS due to its role in the development of the intrinsic innervation and ganglia of the smooth musculature and the association of RET variants with another motility disorder (Hirschsprung's disease). Accordingly, we investigated RET-IHPS associations through sequencing of the complete RET coding region in 32 IHPS patients. Genotype frequencies were compared between patients and 48 controls using the Cochran-Armitage trend test or Fischer's test for exact p-values. We found 19 RET variants in IHPS, including polymorphisms in the promoter region (c.-200 G>A and c.-196 C>A). There was no statistically significant difference between the frequencies of the variants in both groups. There was no deviation from the Hardy-Weinberg equilibrium, yet a significant correlation (linkage disequilibrium) for variants in the promoter region, in exons 11, 13, 14 and 19 and in the 3' UTR. We conclude that RET variants are present in IHPS patients yet show no significant statistical association with the IHPS phenotype, suggesting at best an adjuvant role for RET in IHPS.

Infantile hypertrophic pyloric stenosis before 3 weeks of age in infants and preterm babies

Most infantile hypertrophic pyloric stenosis (IHPS) cases are diagnosed between 3 and 12 weeks after birth. Few data exist regarding Asian infants with IHPS who are younger than 3 weeks or are preterm. The goal of this study is to identify unusual clinical manifestations, clinical course, duration of hospital stay, and complications of Asian infants with IHPS who are preterm or younger than 3 weeks of age. From 1991 to 2004, all IHPS patients admitted to three tertiary centers in southern Taiwan were enrolled. The clinical manifestations, duration of hospital stay and complications were further compared between the IHPS patients diagnosed before and after 3 weeks; preterm and term infants. A total of 214 patients were enrolled into the study; the mean age of diagnosis was 40 days of age; the average duration of hospital stay was 6.27 days. Eighteen (8.41%) patients were diagnosed before 3 weeks of age. A significantly shorter timeframe of diagnosis, a higher rate of jaundice, a lower daily body weight gain and longer duration of hospital stay were noted in the IHPS group prior to 3 weeks compared with those in IHPS group after 3 weeks. Eighteen were preterm infants. A significantly older age of symptom onset, a lower body weight at admission, more cases diagnosed by barium meal study and higher postoperative complication rates were noted in the preterm group versus full-term infants with IHPS. The IHPS cases diagnosed before 3 weeks of age had longer duration of hospital stay. Preterm infants with IHPS had more postoperative complications.

Epidemiological features of infantile hypertrophic pyloric stenosis in Taiwan: A national study 1996–2004

The incidence of infantile hypertrophic pyloric stenosis (IHPS) varies among different countries and is supposed to be lower in Asian countries than in Western countries. However, the incidence of IHPS in Taiwan has not been well investigated. The National Health Insurance (NHI) program was implemented in Taiwan in 1995 and covers most of the population (>99%). We used the NHI database to investigate the epidemiological features of IHPS in Taiwan and to compare the data with that of other countries. We identified 962 new IHPS cases during the period from 1996 to 2004. The overall incidence of IHPS was 0.39 (0.34-0.50) cases per 1000 live births. The estimation was 0.39-0.59 per 1000 live births after adjustment for the misdiagnosis rate. The peak incidence (0.58 per 1000 live births) occurred in winter in 1999. Rates were consistently higher in male subjects. The 1-year survival rate was not significantly different in the patients receiving pyloromyotomy in medical centers, regional hospitals, and district hospitals (P=0.389). Taiwan had the second lowest incidence of IHPS reported in the medical literature. IHPS patients can be successfully treated in district and general hospitals with good prognosis.

The Clinical Features and Management of IHPS: A Comparison between 1980's and 2000's

Purpose: A precise and simple tool for diagnosis and the growing public interest in health caused infantile hypertrophic pyloric stenosis (IHPS) to be diagnosed in good time. The approach to pyloromyotomy as the standard treatment is undergoing changes. We compared 2000’s IHPS patients with 1980’s to identify the clinical features and management. Methods: We analyzed, retrospectively, the clinical findings, diagnoses, and treatment of 68 patients with IHPS who underwent pyloromyotomy at Ewha Womans University Medical Center from January 2000 to December 2008 (2000’s group), and compared the results with that of 42 patients in the 1980’s (1980’s group). Results: There were no significant differences in age, gender, birth rank, seasonal distribution, and symptoms between both groups, but the number of patients with metabolic changes and palpable ‘olive’ was significantly lesser in the 2000’s group. Upper gastrointestinal series (UGI) was the most common imaging tool in the 1980’s (71.4%) but USG has become the standard diagnostic tool in the 2000’s (88.2%). All patients received open pyloromyotomy using traditional incision in the 1980’s, and supraumbilical semicircular incision in 36.8% of patients in the 2000’s. The average length of hospital stay after operation was significantly shorter in the 2000’s group. In the 2000’s, the mean preoperative stay at hospital was 4.4±4.3 days. Twenty-nine (42.0%) patients did not vomit postoperatively and postoperative vomiting did not delay discharges of any patients. Conclusion: There were significant improvements in diagnosis and treatment in the 2000’s. We suggest that the surgeon, without the need for a radiologist perform USG for IHPS in order to shorten the preoperative hospital stay.

Low Plasma Nitrite in Infantile Hypertrophic Pyloric Stenosis Patients

There is now substantial evidence that reduced expression of neuronal nitric oxide synthase (nNOS) is implicated in the pathogenesis of infantile hypertrophic pyloric stenosis (IHPS). This study aimed to investigate the role of plasma nitric oxide (NO) in patients with IHPS. Blood and pylorous biopsies of 13 IHPS patients were examined. The control group consisted of 19 age-matched healthy infants and 22 age-matched acute gastroenteritis patients. Plasma nitrite (NO(2-)) and nitrate (NO(3-)) levels were detected with an NO analyzer. Pylorus biopsies of 13 IHPS patients were examined for nitric oxide synthase isoform expression. Plasma nitrite levels in the 13 IHPS patients were significantly lower than in the age-matched healthy controls (0.97 +/- 0.19 vs. 3.53 +/- 0.79 microM; P < 0.001) and the acute gastroenteritis controls (0.97 +/- 0.19 vs.1.39 +/- 0.45 microM; P = 0.006). Decreased expression of nNOS in the nerve fibers of the pylorus circular muscle was found in the 13 IHPS patients. The decreased plasma nitrite levels rose to the normal range (3.27 +/- 0.77 M) after pyloromyotomy. There was no significant correlation between plasma nitrite levels and muscle wall thickness in IHPS patients. We conclude that NO is implicated in the occurrence of IHPS and the plasma nitrite level is valuable for the diagnosis of IHPS.

ORAL MICROVASCULAR NETWORK GEOMETRY ABNORMALITIES IN INFANTILE HYPERTROPHIC PYLORIC STENOSIS

Infantile hypertrophic pyloric stenosis (IHPS) is a common surgical condition of unknown etiology. The oral mucosal vascular networks of IHPS patients (n=25) and their unaffected parents showed lower blood vessel-free areas, as well as higher box-counting dimensions at two box size scales [D(1–46), D(1–15)], and relative Lempel-Ziv values (P&lt;0.000001), as compared to those of gender- and age-matched controls. These findings may provide a useful phenotypical marker for identifying couples potentially at risk for the birth of an affected infant, while supporting the importance of a genetic component in this condition.

P0146 PP PLASMA NITRITE AND MUSCULAR NEURAL NITRIC OXIDE SYNTHASE IN INFANTILE HYPERTROPHIC PYLORIC STENOSIS

Introduction: Nitric oxide (NO) is well known to participate in the regulation of smooth muscle contractility. We sought to investigate whether plasma NO and pylorus NO synthases (NOS) expression are involved in infantile hypertrophic pyloric stenosis (IHPS). Methods: Blood and pylorous biopsies from thirteen IHPS patients were studied and compared to age-matched normal infants. Plasma nitrite (NO2-) and nitrate (NO3-) levels were detected by an NO analyzer. Pylorus biopsies were collected for immunohistochemical identification of NOS isoform expression in nerve cells, fibers and endothelium in the pyloric muscles. Results: Plasma nitrite levels in the 13 IHPS patients were lower than in the age-matched control group (0.97+/− 0.19uM vs. 3.39 +/− 0.80uM, p<0.001), although the plasma nitrate levels were no different between the two groups (47.75 +/−17.02uM vs. 47.33+/− 27.57uM, p=0.96). Patients with IHPS were determined to have muscular hypertrophy of the circular muscle of the pylorus on pathological examination. Moreover, it was found that in the nerve fibers of the pylorus circular muscle biopsies from 13 IHPS patients there was an absence of neuronal NOS (nNOS) expression as determined by immunostaining. In contrast, nNOS immunostaining was detectable in the pylorus circular muscle biopsies from 9 normal controls. The decreased plasma nitrite levels returned to normal (3.27 +/− 0.77uM) after surgical pyloromyotomy. Conclusion: Lower nNOS expression, combined with decreased plasma nitrite, may be responsible for pylorospasm in infantile hypertrophic pyloric stenosis. The lower nitrite levels in IHPS patients recovered after surgical myotomy of the pylorus, suggesting that pharmacological modulation of nNOS expression or NO production in the gut may serve as an alternative treatment for infants without surgery.

Changes in gastric myoelectrical activity in hypertrophic pyloric stenosis and after surgical correction.

The changes of gastric myoelectrical activity were investigated in 20 infants by cutaneous electrogastrography (EGG) before and after the surgical correction of infantile hypertrophic pyloric stenosis (IHPS). The dominance of 2-4 cycles per minute (CPM) "slow waves" is typical of the healthy gastric function. The shift of the dominant frequencies towards the slower frequency (0-2 CPM) is defined as bradygastria, whereas a shift towards the more frequent waves (4-10 CPM) is called tachygastria. Unlike with healthy infants, the electrogastrogram showed pathologic patterns in 85% (18 out of 20) of IHPS patients. In all except two of these infants with pathologic electrical patterns, the frequency of the waves significantly shifted towards tachygastria. The effect of feeding on the gastric myoelectrical activity could only be studied in limited (9/20) cases because of recurring vomiting during the preoperative period. In IHPS infants, a significant increase in the bradygastria group was observed in the postprandial period compared with healthy infants. Three to 5 days after surgical repair (pyloromyotomy) and the reintroduction of feeding in gradually increasing amounts, the gastric myoelectrical activity showed physiologic patterns again, showing that the pyloric function was back to normal. Cutaneous EGG is a useful, noninvasive method to obtain indirect information about the motor function of the stomach and might be further applicable to pediatric gastric motility disorders.

Single-nucleotide promoter polymorphism alters transcription of neuronal nitric oxide synthase exon 1c in infantile hypertrophic pyloric stenosis.

Infantile hypertrophic pyloric stenosis (IHPS), characterized by enlarged pyloric musculature and gastric-outlet obstruction, is associated with altered expression of neuronal nitric oxide synthase (nNOS). Here we have studied molecular mechanisms by which nNOS gene expression is altered in pyloric tissues of 16 infants with IHPS and 9 controls. A significant decreased expression of total nNOS mRNA was found by quantitative RT-PCR in IHPS after normalization against GAPDH, which predominantly affected exon 1c with a reduction of 88% compared with controls (P < 0.001). After normalization against the neuronal-specific gene PGP9.5, expression of exon 1c was still decreased (P < 0.001), whereas expression of exon 1f was increased significantly (P = 0.001), indicating a compensatory up-regulation of this nNOS mRNA variant. DNA samples of 16 IHPS patients and 81 controls were analyzed for nNOS exon 1c promoter mutations and single-nucleotide polymorphism (SNP). Sequencing of the 5'-flanking region of exon 1c revealed mutations in 3 of 16 IHPS tissues, whereas 81 controls showed the wild-type sequence exclusively. Carriers of the A allele of a previously uncharacterized nNOS exon 1c promoter SNP (-84G --> A) had increased risk for development of IHPS (odds ratio, 8.0; 95% confidence interval, 2.5-25.6). Reporter gene assays revealed an unchanged promoter activity for mutations but a approximately 30% decrease for the -84A SNP (P < 0.001). In summary, our findings indicate that genetic alterations in the nNOS exon 1c regulatory region influence expression of the nNOS gene and may contribute to the pathogenesis of IHPS.

Motor abnormality in the gastroduodenal junction in patients with infantile hypertrophic pyloric stenosis

Background/Purpose: Periodic clusters of phasic pressure waves in the gastroduodenal junction (GDJ) have been seen in patients with infantile hypertrophic pyloric stenosis (IHPS). This study investigated the details of these pressure waves in relation to disturbed transpyloric flow in IHPS. Methods: Manometric study was performed in 11 IHPS patients before and after atropine therapy and 2 non-IHPS infants. Pressure changes in the GDJ were measured with an 8-channel sleeve or a 9-channel sidehole micromanometric assembly under fluoroscopic control for 2 hours. Results: Clusters of phasic pressure waves (365 ± 42 mm Hg) associated with an increase in basal pressure (10 ± 3 mm Hg) were intermittently observed in the GDJ in all IHPS patients. Similar observations were not made in the non-IHPS infants. Most antral pressure waves occurred simultaneously with those pressure waves in the GDJ in the IHPS patients. Atropine (0.01 mg/kg) transiently abolished the phasic and tonic pressure waves for 19 ± 10 minutes. Significantly fewer phasic pressure waves were observed after atropine therapy. Conclusions: Characteristic phasic and tonic contractile activity in the GDJ is uncoordinated with the antral contractions in IHPS patients. Such incoordination may be an important factor in the disturbed transpyloric flow in IHPS. J Pediatr Surg 36:1641-1645. Copyright © 2001 by W.B. Saunders Company.

Selective neurotrophin deficiency in infantile hypertrophic pyloric stenosis

Background/Purpose: Increasing evidence suggests that the enteric nervous system is under the control of neurotrophins. Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4/5 (NT-4/5), promote differentiation, growth, and survival of various central and peripheral nervous system neurons. The biological effects of neurotrophins are mediated by the interactions with high-affinity tyrosine kinase receptors (TrkA, TrkB, TrkC). Recently, abnormalities of intramuscular innervation have been reported in infantile hypertrophic pyloric stenosis (IHPS). To further understand the reported abnormalities in pyloric innervation in IHPS, the authors analyzed the expression of Trk receptors and the neurotrophins content in IHPS. Methods: Full-thickness muscle biopsy specimens were obtained from 8 IHPS patients (age range, 23 to 41 days) at pyloromyotomy and from 8 age-matched controls without gastrointestinal disease at autopsy performed within 12 hours after death. Indirect immunohistochemistry was performed using ABC (Avidin Biotin peroxidase Complex) method with anti-Trk specific antibodies (A,B,C). Quantitative analysis was performed using sandwich-type ELISA for NGF, BDNF, NT-3, and NT-4/5. Results: The intensity of staining of the myenteric plexus for TrkA, TrkB, and TrkC was similar among IHPS and controls. There was a lack of TrkA-positive nerve fibers in IHPS compared with controls. The quantity of total NGF, NT-3, and BDNF in IHPS was significantly lower than in controls. Conclusions: The reduced production of neurotrophins in IHPS may be responsible for the delay in the functional and structural maturation of pyloric innervation in IHPS. The lack of TrkA-positive nerve fibers in pyloric muscle may explain the abnormal intramuscular innervation in IHPS. J Pediatr Surg 36:1280-1284. Copyright © 2001 by W.B. Saunders Company.

Glial-derived growth factor signaling pathway in infantile hypertrophic pyloric stenosis

Background/Purpose: Glial-derived growth factor (GDNF), which is the ligand of RET is reported to be essential for the development of enteric nervous system. A GDNF knockout mouse model has shown that the gastric region is a critical passing site between GDNF-RET-independent neuroblasts (colonizing the esophagus) and GDNF-RET-dependent neuroblasts (colonizing the small and large bowel). The earliest GDNF site of production is the mesenchyme and the outer smooth muscle cell (SMC) layer of the developing bowel. In the mature gastrointestinal tract the presence of GDNF is restricted to enteric glial cells. The aim of this study was to investigate the expression of GDNF and RET in infantile hypertrophic pyloric stenosis (IHPS). Methods: Full-thickness muscle biopsy specimens were obtained from 8 IHPS patients at pyloromyotomy and from 8 age-matched controls without gastrointestinal disease. Indirect immunohistochemistry was performed using avidin-biotin-peroxidase complex method with anti-GDNF and anti-RET antibodies. Quantitative analysis was performed using sandwich-type enzyme-linked immunosorbent assay (ELISA) for GDNF. Results: GDNF- and RET-positive nerve fibers were absent or markedly reduced in IHPS compared with controls. GDNF was expressed strongly by smooth muscle cells of both muscular layers in IHPS, whereas no GDNF expression was detected in pyloric muscle of controls. The quantity of total GDNF in IHPS was significantly higher than in controls (P <.01). Conclusions: The lack or markedly decreased number of GDNF-positive nerve fibers in IHPS supports the hypothesis of a selective immaturity of the enteric glia in the muscular layers in IHPS. The strong expression of GDNF in smooth muscle cells in IHPS and the increased levels of GDNF in IHPS suggest a compensatory mechanism by which the smooth muscle cells continue to produce GDNF until maturation of the enteric glial cells occurs. J Pediatr Surg 35:835-839. Copyright © 2000 by W.B. Saunders Company.

Structural immaturity of the pylorus muscle in infantile hypertrophic pyloric stenosis.

Recent reports indicate that extracellular matrix and cytoskeleton plasmalemmal elements are altered in infantile hypertrophic pyloric stenosis (IHPS). Desmin is a cytoskeletal protein that is important for the organization and function of muscular fibers. It has been found to be increased in the smooth muscle in chronic intestinal pseudo-obstruction and in skeletal muscle in some forms of myopathies as well as in unexplained hypertrophic cardiomyopathies. The aim of this study was to analyze the expression of desmin in IHPS. Full-thickness muscle-biopsy specimens were obtained from 8 IHPS patients (age range 23 to 41 days) at pyloromyotomy, from 8 age-matched controls without evidence of gastrointestinal (GI) disease at autopsy, and from 2 stillborns who died at 27 and 30 weeks of gestation without evidence of GI disease. Indirect immunohistochemistry was performed using the avidin-biotin-peroxidase complex method with anti-desmin and visualized by development with 3-diaminobenzidine tetrahydrochloride. Pyloric muscle in IHPS demonstrated strong desmin immunoreactivity. The expression of desmin was also strong in the muscular layers of fetal pylorus. In the age-matched controls absent or weak desmin immunoreactivity was seen in the pyloric muscle layer. The increased amount of desmin in hypertrophied pyloric muscle in IHPS may result in inco-ordination of contraction and relaxation of the pylorus, thus causing motility dysfunction. The similar pattern of desmin expression in IHPS and fetal pylorus suggests that the organization of intermediate filaments in IHPS is in a fetal stage of development.