Tracheo-oesophageal fistula and oesophageal atresia

Summary
Introduction
Associations
Investigation
Management
Areas of Uncertainty in Clinical Practice
References

Summary

early diagnosis is important to minimise pulmonary complications
regular, thorough suctioning of the upper oesophageal pouch is required prior to definitive surgical repair
referral to a level III neonatal surgical unit and the neonatal transport service should be made as soon as possible

Introduction

The aetiology of tracheo-oesophageal fistula (TOF) is not known. Disruption during development of the embryonic trachea and oesophagus in the fourth week of fetal life results in the persistence of fistulas between them and may result in incomplete oesophageal development.

The incidence of oesophageal atresia (OA) is approximately 1 in 3000 to 4500 births.

These infants are more likely to be premature because of the high association with polyhydramnios. In the most common variant of the disorder (approximately 86% of cases) the upper oesophageal segment ends in a blind pouch with a fistula connecting the distal oesophageal segment to the trachea, at or close to the carina. The uncommon variants include OA without a fistula, TOF from the proximal oesophageal pouch and isolated (H-type) TOF.

FIGURE 3. Successive stages in the development of the tracheoesophageal septum during embryologic development. (A) The laryngotracheal diverticulum forms as a ventral outpouching from the caudal part of the primitive pharynx. (B) Longitudinal tracheoesophageal folds begin to fuse toward the midline to eventually form the tracheoesophageal septum. (C) The tracheoesophageal septum has completely formed. (D) If the tracheoesophageal septum deviates posteriorly, esophageal atresia with a tracheoesophageal fistula develops.
From American Academy of Family Physicians http://www.aafp.org/afp/990215ap/910.html

The first clinical sign of OA is that of excessive oral secretions. Choking and regurgitation accompany feeding. Abdominal distension (due to air transmitted through the distal fistula), aspiration of secretions from the upper pouch and reflux of acidic gastric contents via the fistula to the lungs may all contribute to respiratory compromise.

The infant with H-type TOF may present insidiously but usually coughs and chokes with feeding.

Associations

congenital heart disease, intestinal atresia, imperforate anus, skeletal anomalies and renal anomalies suggest the VACTERL association: Vertebral, Anal, Cardiac, Tracheal, ‘Esophagus’, Renal and Limb

oesophageal atresia may also be seen in the CHARGE association: Coloboma, congenital Heart disease, choanal Atresia, growth and mental Retardation, Genital hypoplasia, Ear anomalies

Investigation

Diagnosis may be suggested on antenatal ultrasound with polyhydramnios (present in approximately 60% of cases) or the failure to detect the fetal stomach.

If the diagnosis is suggested antenatally, or there are clinical signs at birth, an attempt should be made to pass a firm suction catheter or feeding tube (size 10F is adequate) to the stomach before the first feed. The inability to pass the tube into the stomach confirms the diagnosis of OA. Most often the tube comes to a halt at about 9 to 13cm from the gums (although this will depend on the size and gestation of the baby). A smaller, softer tube may curl up in the upper oesophageal pouch giving a false negative result.

A chest and abdominal X-ray taken with the catheter tip in the pouch will confirm the position of the upper oesophageal pouch and air within the bowel confirms the presence of a distal tracheo-oesophageal fistula. Contrast in the upper pouch is usually not required. The absence of air below the diaphragm excludes a distal fistula. If an H-type TOF is suspected this is usually revealed by a contrast swallow.

Echocardiography will be required to exclude cardiac anomalies and to establish the position of the aortic arch.

Renal ultrasound should be performed if the neonate is anuric to exclude bilateral renal agenesis (although the baby would be expected to be in extremis from respiratory failure secondary to pulmonary hypoplasia) or severe dysplasia as this may preclude surgical intervention. Renal ultrasound should also be considered if there are other features suggesting the VACTERL association.

Management

The neonate must be kept nil by mouth, commenced on intravenous fluids and nursed supine in a head up position (approximately 30 to 60 degrees). The upper pouch must be kept clear of secretions by frequent suctioning.

Antibiotics are recommended if there is evidence of aspiration pneumonia.

The patient should be transported to a level III surgical neonatal unit as soon as possible. In most cases early primary surgical repair is appropriate.

The presence of coexisting severe anomalies or extreme prematurity may impact on the likelihood of survival.

Areas of Uncertainty in Clinical Practice

Some neonatal units recommend that all babies have a small nasogastric tube (e.g. size 5) passed down each nostril and into the stomach soon after birth so that most cases of OA and choanal atresia can be detected before the first feed. However, this practice is not universally accepted.

References

Avery, G.B., Fletcher, M.A., and MacDonald, M.G. (editors). Neonatology: Pathophysiology and Management of the Newborn. 5^th edition. Lippincott, Williams & Wilkins. 1999.

Levene, M.I., Tudehope, D.I., and Thearle, M.J. Essentials of Neonatal Medicine. 3^rd edition. Blackwell Science. 2000.

Hutson, J.M., Woodward, A.A., Beasley, S.W. (editors). Jones’ Clinical Paediatric Surgery, Diagnosis and management. 5^th edition. Blackwell Science Asia. 1999.

Ashcraft, K.W., Murphy, J.P., Sharp, R.J., Sigalet, D.L., Snyder, C.L. (editors). Pediatric Surgery. 3^rd edition. W.B. Saunders Company. 2000.