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

Abstract

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.

Background

Oesophageal atresia (OA) is one of the most common congenital malformations of the gastrointestinal tract with an incidence of 1 in 3000 live births.¹ OA is a severe congenital anomaly. The aetiology remains unclear, although many factors have been identified, and this anomaly has been reported to arise from a disorder in organogenesis.²

In hypertrophic pyloric stenosis (HPS), the pyloric muscle is hypertrophied, and the pyloric canal becomes narrow and elongated, which causes gastric outlet obstruction. Pathogenesis is still unclear, and the incidence is 3 in 1000 live births, although the incidence rate varies among different geographical regions and ethnic populations. HPS is 30 times more common than oesophageal atresia.^3–5

HPS may develop following OA operation.2 4 6 7 Although this association has been well established in the literature, there is no consensus on the underlying pathophysiological process. In this study, we consider a case of HPS that occurred following repair of OA and tracheo-oesophageal fistula (TOF), which is worthy of presenting due to its rare occurrence.

Case presentation

A baby girl who weighed 3000 g, born to a 26-year-old mother from her fifth pregnancy via spontaneous vaginal delivery at 38 weeks of gestation, was admitted to the neonatal intensive care unit due to respiratory distress. APGAR scores were 7 and 9 at 1 and 5 min, respectively. The mother and father were not consanguineous, and antenatal controls of the baby had shown no pathological finding. Physical examination revealed increased oral secretions in the baby, and there were bilateral crackles on pulmonary auscultation.

Investigations

After failed attempts to insert a nasogastric tube into the stomach, an X-ray was obtained with water-soluble contrast agent, which showed a blind oesophageal upper end (figure 1). The patient underwent surgery on the second day of her life, and she was diagnosed to have type C OA according to Gross’ classification (proximal atresia+distal fistula).⁸ Fistula ligation and primary anastomosis were performed via right thoracotomy.

Figure 1.

Anteroposterior chest X-ray showing the dilated, blind-ending proximal oesophageal pouch (arrow).

Echocardiography revealed atrial septal defect. Abdominal ultrasound (USG) revealed normal findings. Feeding via a nasogastric tube was attempted at postoperative day 3. However, feeding was discontinued due to the presence of non-bilious residues. Feeding via a nasogastric tube was reattempted at certain intervals, but the volume of feeding could not be increased due to non-bilious vomiting. Direct X-rays with contrast agent did not show oesophageal stricture. Abdominal X-ray with contrast ingestion showed remarkably enlarged stomach (figure 2), but intestines were observed normally in terms of other intestinal pathologies including malrotation, midgut volvulus, intestinal atresia, meconium ileus, Hirschsprung’s disease and necrotising enterocolitis. On abdominal USG, the thickness of the pyloric muscle was 5 mm, and the length was 17 mm, after which the patient was diagnosed with HPS.

Figure 2.

An abdominal X-ray demonstrating grossly dilated stomach (arrow).

Differential diagnosis

Vomiting in the neonates is a common presenting complaint with aetiologies ranging from benign to life threatening. Common causes of bilious vomiting due to obstructive pathologies are malrotation, midgut volvulus, intestinal atresia, duplication cysts, meconium ileus and Hirschsprung’s disease.^{9 10} HPS and gastro-oesophageal reflux (GOR) are the most common causes of non-bilious vomiting in the newborn. Other conditions that can present with non-bilious vomiting include pylorospasm, hiatal hernia, inguinal hernia, preampullary duodenal stenosis, sepsis and inborn errors of metabolism.^{9 11} Oesophageal stricture, GOR, oesophageal dysmotility, HPS and antral web should be considered in case of vomiting or feeding intolerance following repair of OA+TOF.2 4 6 7

We excluded the obstructive pathologies which lead to bilious vomiting, as our patient had non-bilious vomiting and radiographic studies of intestines were normal. Rare causes of non-bilious vomiting were ruled out by physical examination, laboratory tests and imaging studies including X-ray of abdomen and abdominal USG.

Treatment

The patient underwent surgery with the diagnosis of HPS at 15 days of life using the Ramstedt pyloromyotomy technique (figure 3). The patient was intubated during the follow-up period due to right-sided atelectasis in the postoperative period. Feeding via nasogastric tube was initiated at postoperative day 5 with incremental volume, and complete enteral feeding was achieved at day 38 after surgery. Recurrent atelectasis and episodes of pneumonia were observed during the follow-up on the hospital. Anastomotic stricture or leakage were excluded by oesophagram. The test was negative for a mutation in the cystic fibrosis transmembrane conductance regulator gene for diagnosing of cystic fibrosis. After repeated antibiotic therapies, the atelectasis and pneumonia were resolved.

Figure 3.

Intraoperative photograph showing the hypertrophied pyloric muscle during the pyloromyotomy.

Outcome and follow-up

The patient put on weight during the follow-up and was discharged on day 70 of life. Our case was continued to be monitored for long-term complications that may occur as a result of abdominal surgery, including postoperative ileus, anastomotic stenosis and pulmonary and gastrointestinal complications. She was admitted to the hospital because of pneumonia and vomiting episodes at 5 months of age. We performed oesophagogram and ruled out the anastomotic stricture. Although we could not perform impedance test to detect GOR, it was considered that the pneumonia might be caused by aspiration due to GOR. The patient is currently 6 months old and in the 10th percentile for weight and height.

Discussion

OA is the most common oesophageal malformation. The present case had type C OA which is the most common variation with a rate of 86%.^{2 5 8}Patients with OA have short oesophagus and dysmotility. Thus, these patients require monitoring for the development of GOR. Approximately 50%–95% of the operated cases often develop GOR symptoms, such as dysphagia and airway disorders, which do not require medical or surgical therapy.¹²

When compared with general population, HPS is more often observed in patients who undergo surgery for OA+TOF.2 4 6 7 Foster and Shaw¹³ reported the association between OA and HPS for the first time in 1946. Palacios et al⁶ reported HPS in 3.3% of 61 patients they operated due to OA. van Beelen et al⁴ reported HPS in 7.5% of 267 patients who underwent surgery for OA. In the study by Deurloo et al⁷ reporting on 371 patients, the rate of HPS was 13% in cases with OA and 6% in cases with OA+TOF.

Symptoms due to HPS typically occur at 2 to 8 weeks of age and peak at 3 to 5 weeks. Progressive hypertrophy of the pyloric muscle prevents gastric discharge. This causes classical symptoms, such as worsening projectile vomiting after feeding. Vomits which are without bile may cause dehydration and hypochloraemic, hypokalaemic metabolic alkalosis if left untreated. Although many studies have been conducted, to our knowledge, the aetiological factors for HPS and pathophysiological mechanisms have not been elucidated. Maternal risk factors, such as nitric oxide synthase deficiency, infections, genetic predisposition, smoking, hyperthyroidism and young age and factors such as the use of erythromycin or azithromycin in the first 2 weeks of life, prematurity, and bottle feeding are some hypotheses proposed to account for the development of HPS.¹⁴ USG is the most important imaging modality that is used to diagnose HPS, which yields a sensitivity of specificity of 100% in experienced hands. The thickness of the pyloric muscle of greater than 3 mm and pyloric canal length greater than 12 mm on USG or lack of gastric passage from the stomach to the duodenum on X-ray with contrast ingestion are findings favouring the diagnosis of HPS.^{14 15}

Vagal injury, the performance of gastrostomy and transpyloric feeding tubes, genetic or epigenetic causes are factors that are thought to be involved in an increased incidence of HPS following surgery for OA+TOF.^{7 16–20} Vomiting can be observed in the first couple of days following abdominothoracic surgery, particularly after surgery for OA+TOF, and vomits are often associated with reflux or stenosis on the anastomosis line. HPS is not suspected in most patients as clinical findings, and symptoms associated with HPS are often masked, which causes a delay in the diagnosis of HPS. Thus, even a low index of suspicion for HPS mandates radiographic imaging of the stomach and the duodenum with contrast enhancement.^{4 21–23} The present case had projectile bile-free vomiting after feeding in the absence of gastrostomy and transpyloric feeding tube. In our case, local irritation caused by continuous gastric decompression could be an aetiological factor for the development of HPS.

Laparoscopic pyloromyotomy has become increasingly popular over time for the treatment of HPS, although the safety and efficacy of this method are still controversial when compared with open pyloromyotomy. Several systemic reviews demonstrated laparoscopic pyloromyotomy to be superior to open pyloromyotomy in terms of shorter time to achieve full enteral feeding, decreased complication rates, better long-term cosmetic outcome, reduced postoperative recovery times and costs, however, laparoscopic pyloromyotomy is associated with increased risk of incomplete pyloromyotomy. Our patient underwent open pyloromyotomy because of the surgeon’s choice.¹⁴

Anastomotic stricture is the main complication following operative repair of OA. GOR is the most common long-term complication of OA+TOF due to both intrinsic dysmotility and structural factors. OA+TOF patients have increased risk of aspiration owing to oesophageal dysmotility, GOR or oesophageal stricture. Repaired OA+TOF is also associated with long-term respiratory morbidity including recurrent respiratory tract infection, chronic cough, persistently abnormal pulmonary function and reported asthma.^{1 24 25} Our patient was admitted to the hospital at the 5 month of age because of pneumonia which was caused by possible aspirations due to GOR.

OA can be accompanied by additional anomalies in 46% of the cases. The most common comorbid anomalies include congenital heart defect (23%), gastrointestinal tract anomalies (20%), associations (VACTERL, CHARGE) (17%), urinary tract malformations (14%) and skeletal system anomalies (7%).²⁶ VACTERL association is typically defined by the presence of at least three of the following congenital malformations: vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities. CHARGE syndrome is a multiple congenital anomaly syndrome characterized by the variable combination of multiple anomalies, mainly coloboma; choanal atresia/stenosis; cranial nerve dysfunction; characteristic ear anomalies. The present case had three components of VACTERL, namely OA, TOF and cardiac defect (atrial septal defect).

In conclusion, there is an increased prevalence of HPS in patients who undergo surgery for OA+TOF. Thus, although rarely observed, HPS should be kept in mind in patients with recurrent and persistent vomiting and feeding difficulties after surgery, and necessary imaging studies must be performed to avoid any delay in the diagnosis and treatment.

Learning points.

• Hypertrophic pyloric stenosis (HPS) has an incidence of 3 in 1000 live births and 30 times more common than oesophageal atresia (OA).

• There is an increased prevalence of HPS in patients who undergo surgery for OA and tracheo-oesophageal fistula (TOF).

• HPS should be kept in mind in patients with recurrent and persistent vomiting and feeding difficulties following repair of OA+TOF, therefore, necessary imaging studies must be performed to avoid any delay in the diagnosis and treatment.