Hypertrophic pyloric stenosis following persistent pulmonary hypertension of the newborn: a case report and literature review

BACKGROUND

Although persistent pulmonary hypertension of the newborn (PPHN) and infantile hypertrophic pyloric stenosis (HPS) are both well-known diseases that occur in early infancy, PPHN complicated by HPS is rare. As nitric oxide (NO) is an important mediator of biological functions, on both the vascular endothelium and smooth muscle cells, the decreased production of NO might play a role in the pathogenesis of both PPHN and HPS. We present the case of a neonate who developed HPS following PPHN, including a detailed review on research published to date, and we discuss the pathogenesis of PPHN and HPS.

CASE PRESENTATION

A female neonate born at 38 weeks of gestation, weighing 3140 g, developed PPHN due to meconium aspiration syndrome. Intensive treatment with high frequency oscillations and inhaled NO were initiated, and sildenafil and bosentan were added. She gradually recovered. At 15 days of age, the patient developed recurrent vomiting after feeding and the diagnosis of HPS was made. Intravenous atropine therapy was started at 20 days of age, but the efficacy was clinically unsatisfactory. The coadministration with transdermal nitroglycerin improved the symptoms, and oral feeding was successfully re-introduced.

CONCLUSIONS

Our patient recovered from both PPHN and HPS using NO-related medications. A decrease in NO synthesis is likely to be a common pathway for PPHN and HPS.

Gastric outlet obstruction in pediatric patients

BACKGROUND

This study reports the etiologies, management and outcome of children with gastric outlet obstruction (GOO) in a children's hospital.

METHODS

The medical records of 11 children with GOO not associated with idiopathic hypertrophic pyloric stenosis (IHPS) were reviewed. They were categorized into one group of anatomic abnormality (AA group) and one group of peptic ulcer disease (PD group). One case underwent episodes of GOO caused by anatomic abnormality and peptic ulcer disease, respectively.

RESULTS

Six cases belonged to the AA group. Mean age was 58 months with a male to female ratio of two to four. Underlying etiologies were prepyloric mass (2), web (2) and gastric volvulus (2). Four patients underwent surgery. One patient was lost to follow-up. GOO did not recur in the follow-up period (mean duration 24 months) in the remaining cases. One case in the AA group and the remaining five patients composed the PD Group. Mean age was 49 months and all were male. Underlying causes were gastric ulcers (4) and chronic duodenal ulcers (2). Two of the five patients had Helicobacter pylori infection found by rapid urease test. Four patients recovered after medical management and another two, with normal serum gastrin levels, underwent surgery because of poor response to medical treatment. One case was lost to follow-up. No recurrence of GOO was noted in the follow-up period (mean duration 27 months) in the remaining cases.

CONCLUSIONS

In our study, peptic ulcer disease was as important as anatomic abnormalities as the etiology for GOO not associated with IHPS, and medical management could release GOO caused by it. Compared to adult patients, H. pylori infection played a less important etiologic role in pediatric patients with GOO.

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.

Helicobacter pylori and infantile hypertrophic pyloric stenosis: is there a possible relationship?

BACKGROUND

Recently, it has been suggested that Helicobacter pylori might be a cause of some cases of infantile hypertrophic pyloric stenosis (IHPS) in infancy on the basis of its epidemiologic and clinical features. We performed this study to evaluate the possible relationship between IHPS and H. pylori.

DESIGN

In consecutive infants with IHPS, we performed upper gastrointestinal endoscopy with biopsy before pyloromyotomy. The endoscopic appearance of the pylorus was noted to validate endoscopic features of IHPS.

RESULTS

Sixteen infants, 15 male, 14 white, mean age 42 days, range 21 to 104 days, were studied. The index case had chronic active gastritis on biopsy with organisms suspicious for H. pylori. Four others had chronic active gastritis, six more had focal or mild chronic gastritis, five were normal, and none had H. pylori on histology or immune histochemical staining in selected cases. All patients had negative rapid urease test. Most common endoscopic findings of IHPS were thickened prominent asymmetric pyloric folds and pin-hole pylorus that could not be intubated by the pediatric endoscope.

CONCLUSION

H. pylori was not specifically identified in our patients with IHPS. The presence of H. pylori-like organisms in the gastric mucosa in our index case and finding of chronic active gastritis in several others may indicate the possibility of an acquired infectious etiology for IHPS.

Hypertrophic pyloric stenosis in twins: same genes or same environments?

The aetiology of infantile hypertrophic pyloric stenosis (IHPS) remains obscure. Cases in twins, usually monozygotic, have been sporadically reported as evidence for the genetic origin of the disease. We present a case of IHPS in a pair of dizygotic male twins together with a review of the literature, focusing on the question of whether the twin cases actually support a genetic or an acquired nature of IHPS.