June Issue.indd

G.V.S. Murthi, S. Nour
Department of Paediatric Surgery, University Hospitals of Leicester, Leicester Royal Infirmary, LE1 5WW, UK

Correspondence to: G.V.S. Murthi, 12 Brookside Drive, Oadby, Leicester, LE2 4PB, UK

Introduction

Discussion

References

Keywords: Pyloric stenosis, associations, Jacobsen syndrome
Surg J R Coll Surg Edinb Irel., 2 June 2004, 173-175

Pyloric stenosis is a common paediatric surgical condition with a well-recognised pattern of clinical features. Diagnosis is usually straightforward and a Ramstedt pyloromyotomy is curative. We present three patients who developed pyloric stenosis incidentally during the management of other primary surgical conditions. Issues of diagnostic difficulty following presentation of pyloric stenosis in the post-operative period (all three patients), its rare syndromic associations (one patient) and its management in this unusual situation are discussed. An awareness of the unusual presentations of pyloric stenosis during treatment for other primary surgical conditions can help in earlier diagnosis and treatment

INTRODUCTION
Pyloric stenosis with an incidence of 1.5 to 4 in 1000 live births is a well-recognised clinical condition that is frequently encountered, easily diagnosed (test-feed, ultrasound scan and blood gases) and managed by paediatric surgeons in specialist centres with an excellent outcome.^{1, 2}

Occurrence of pyloric stenosis in the absence of characteristic features (projectile vomiting, metabolic alkalosis and a palpable ‘olive’) can result in diagnostic confusion and prompt investigations looking for other causes. This can lead to a delay in reaching the correct diagnosis.

We present three patients who developed pyloric stenosis incidentally during the management of other primary surgical conditions. Issues of diagnostic difficulty following presentation of pyloric stenosis in the post-operative period (all three patients), its rare syndromic associations (one patient) and its management in this unusual situation are discussed.

Case 1
A term male infant (JB) was diagnosed with oesophageal atresia and tracheo-oesophageal fistula at birth. Following repair, a postoperative contrast study one week later was normal with no stricture of the oesophagus. Naso-gastric tube feeds of 60mls every three hours were tolerated over the next week, except for occasional small vomits associated with choking and cyanosis. An echocardiogram was normal. During the third week of life the infant started to develop increasing frequency and volume of vomits post-feeding. This was associated occasionally with inspiratory and expiratory stridor that required facial O₂ therapy. On day 20 of life an upper gastro-intestinal contrast study was performed. This showed no oesophageal stricture at the site of the anastomosis, mild gastro-oesophageal reflux and delayed emptying of the stomach even on late films, suggesting pyloric stenosis. This was confirmed by an ultrasound examination and the patient underwent a Ramstedt pyloromyotomy through a right upper quadrant incision. Subsequently, because of persistent stridor, cyanosis and life-threatening choking attacks, due to tracheomalacia, an initial tracheopexy and later an aortopexy were performed. There were no further problems and the child is well at eight years of age.

Case 2
A term, male infant (AS) with antenatally diagnosed gastroschisis was delivered satisfactorily by emergency Caesarean section for reduced foetal movements. Birth weight was 3120 grams and clinical examination was normal except for the gastroschisis. Primary closure of the gastroschisis was performed soon after birth. Following an initially uneventful recovery, naso-gastric tube feeds were commenced on the 10th post-operative day. Over the next five days, incremental feeds were tolerated and bottle-feeds of 60ml every three hours was achieved and parenteral nutrition stopped. The infant began to have small vomits on day 16 of life. This vomiting (non-bilious, small volume, mostly post-feeding) continued for the next week, despite change in the feeding formula. During this period repeated clinical examination was unremarkable. Urea and electrolytes and an abdominal radiograph were normal.

On day 23 of life a capillary blood gas sample was normal (pH 7.41, HCO₃ 22.7, base excess 1.4) and an ultrasound scan was consistent with features of pyloric stenosis. On the basis of the scan result, a planned upper gastrointestinal contrast study was cancelled. Ramstedt pyloromyotomy was performed through a right upper quadrant, transverse, musclecutting incision. There were no complications of surgery and the patient made an uneventful recovery achieving full-feeds by the second post-operative day. The child is doing well two years later.

Case 3
A male infant (birth weight 2920 grams) was delivered by normal vaginal delivery at 42 weeks of gestation. Antenatally, a triple test indicated a low risk for Down syndrome and an abdominal scan showed right talipes equinovarus. Postnatally, a diagnosis of Jacobsen syndrome was made on the basis of the following clinical examination (trigonocephaly, a high-arched palate, ptosis right eyelid, concominant squint, right talipes-equinovarus, petechial rash), persistent thrombocytopenia, and chromosomal analysis (11q deletion). Cardiac investigations revealed peripheral pulmonary stenosis and a small atrial septal defect. On day four of life the infant developed bilious vomiting, abdominal distension and fresh blood in the stools and severe metabolic acidosis. Abdominal radiography showed dilated loops of bowel with extensive intramural gas. Necrotising enterocolitis (NEC) was diagnosed and the infant was ventilated and managed conservatively. Two weeks later, the infant was extubated and naso-gastric feeds commenced gradually. He developed jaundice and moderate hepatosplenomegaly as a result of total paranteral nutrition, cholestasis and sepsis. Feeds were not tolerated and the infant developed recurrent abdominal distension and visible bowel loops with visible peristalsis. A contrast enema revealed a stricture in the sigmoid and ascending colon. On day 60 of life a laparotomy for sub-acute bowel obstruction was undertaken and a right hemicolectomy and sigmoid resection for post-NEC strictures with end-to-end anastomosis was performed. In the post-operative period the naso-gastric aspirates initially decreased to minimal volumes by the fourth post-operative day but subsequently, were persistently raised for the next 10 days (clear aspirates, volumes 60 - 170ml/day). Abdominal examination during this period was normal. Blood gas analysis and abdominal radiographs on the 15th post-operative day were normal. Subsequent ultrasound scan of the abdomen revealed a pyloric stenosis. A Ramstedt pyloromyotomy through a separate right upper quadrant incision was performed. The pylorus was adherent to the under surface of the liver and was freed by dissection. The infant is well at six months follow up.

DISCUSSION
Pyloric stenosis typically presents during weeks two to eight of life with non-bilious, projectile vomiting. Visible gastric peristalsis and palpation of an ‘olive’ in the upper abdomen often confirms the diagnosis. Where a test-feed is negative ultrasound measurement of the pyloric dimensions are increasingly used to confirm the diagnosis.3 Dehydration and a hypokalaemic, hypochloraemic, metabolic alkalosis are typical abnormalities. Following correction of fluid and electrolyte abnormalities, Ramstedt pyloromyotomy is standard management. Given its relatively frequent occurrence in the population, it would not be unexpected that pyloric stenosis can occasionally present, coincidentally, in infants with other primary surgical conditions. Persistent vomiting or increased gastric aspirates following abdominal surgery is usually attributed to ‘ileus’. Persistent symptoms usually prompt investigations (plain abdominal radiograph and upper gastrointestinal contrast study) looking for gastro-oesophageal reflux, anastomotic leaks, adhesions or residual disease. Typical symptoms and signs of pyloric stenosis in such patients may be absent, masked or not formally sought. This is because routine post-operative fluid and electrolyte management will pre-empt electrolyte abnormalities from developing, and the difficulty of performing a ‘test-feed’ in this situation, due to an abdominal wound. In the three cases discussed above, duration between onset of symptoms and diagnosis of pyloric stenosis was 5, 8 and 11 days, respectively, despite regular review of their ongoing post-operative care following surgery for their primary condition. Hence, an awareness of the possibility of the coincidental occurrence of pyloric stenosis should result in an ultrasound scan and lead to earlier diagnosis.

In addition to the well-recognised features of pyloric stenosis that suggest a multifactorial genetic predisposition (commoner in first-born males and in certain ABO blood types, and family history), rarer associations of pyloric stenosis with other disease conditions have been described in the literature. Pyloric stenosis has been described in association with oesophageal atresia, cystic fibrosis, Gilbert syndrome, asymptomatic joint hypermobility, hypoplastic or absent mandibular frenulum, epidermolysis bullosa, erythromycin administration and Jacobsen syndrome.^4-11 Its association with Jacobsen syndrome (Case 3) was first described by Schinzel et al. in 1977.12 Grossfeld et al.¹³ in a recent review of children with Jacobsen syndrome found pyloric stenosis in 11/ 74 (15%) patients, including 6/56 females (11%) and 6/33 males (18%)(submitted for publication). This was calculated to be >116x and >45x the frequency in females and males in the general population, respectively. An awareness of the known association between pyloric stenosis and these conditions (as in Case 3) may lead to earlier investigations and diagnosis.

Operative approach can vary between the typical right upper quadrant, supra-umbilical and laparoscopic routes.^14,15 Increasingly, there is a trend towards operation through the supra-umbilical route for cosmetic reasons.¹⁴ In this situation, however, we prefered the right upper quadrant approach as, a scar from a previous operation already existed. Also, adhesions from previous surgery are expected and such an incision provides direct access enabling the adhesions to be visualised and lysed safely.

In conclusion, an awareness of the possibility of the incidental occurrence of pyloric stenosis in the post-operative period and of its association with uncommon conditions will prompt the clinician to think of and investigate for its presence. This should lead to its earlier diagnosis and treatment.

REFERENCES
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