Congenital And Acquired Conditions Of The Oesophagus (Congenital Atresia and TEF)

Question 1

What is oesophageal atresia

Answer 1

Oesophageal atresia is a congenital abnormality in which there is a discontinuity in the lumen of the oesophagus with or without an associated tracheo-oesophageal fistula. A few present only with a tracheo-oesophageal atresia alone or an oesophageal stenosis

Question 2

What is the cause of an oesophageal atresia (OA)

Answer 2

The aetiology of oesophageal atresia is not known. Possible teratogenic risk factors include Methimazole, Contraceptive pill, Thalidomide and Diabetes. Genetic and Chromosomal factors play a role in only a few cases but no single factor can be said to cause oesophageal atresia. It is essentially a sporadic event

Question 3

What is a pathogenesis of an OA

Answer 3

The respiratory tract develops as a ventral pouch of the foregut at about the 4th week of gestation. A tracheo-oesophageal septum then separates the tracheal diverticulum from the oesophagus. An insult at this stage is believed to result in oesophageal atresia. Theories of pathogenesis include: failure of recanalization, in which the lumen is said to continue to obliterate during growth and later fail to recanalise; theory of spontaneous deviation of the tracheo-oesophageal septum in which the tracheo-oesophageal septum deviates from its normal pathway; theory of mechanical pressure, suggesting that high pressures in-utero lead to the atresia and theory of abnormal formation of dorsal folds which lead to abnormal fusion with the tracheo-oesophageal septum. None of these theories fully explains the pathogenesis, however it is suspected to be due to a failure of cellular proliferation, differentiation and apoptosls

Question 4

What are the various theories for an OA

Answer 4

Theories of pathogenesis include: failure of recanalization, in which the lumen is said to continue to obliterate during growth and later fail to recanalise; theory of spontaneous deviation of the tracheo-oesophageal septum in which the tracheo-oesophageal septum deviates from its normal pathway; theory of mechanical pressure, suggesting that high pressures in-utero lead to the atresia and theory of abnormal formation of dorsal folds which lead to abnormal fusion with the tracheo-oesophageal septum. None of these theories fully explains the pathogenesis, however it is suspected to be due to a failure of cellular proliferation, differentiation and apoptosls

Question 5

What is the most common classification of an OA

Answer 5

Gross classification and Vogt classification

Question 6

What is type A OA

Answer 6

Oesophageal Atresia without a fistula (I %). Proximal oesophageal pouch ends blindly; Distal oesophagus
has a blind beginning

Question 7

What is Type B OA

Answer 7

Oesophageal Atresia with an upper tracheo-oesophageal fistula (0.5%). Proximal pouch has a fistulous connection with trachea; Distal oesophagus has a blind beginning

Question 8

What is a type C OA

Answer 8

Oesphageal atresia with a distal tracheo-oesophageal fistula (85%). Proximal pouch ends blindly; Distal oesophagus has a fistulous connection with the trachea

Question 9

What is the most common gross classification of OA

Answer 9

Type C OA

Question 10

What is a type D OA

Answer 10

Oesophageal atresia with a double fistula (0.5%). Proximal pouch has a fistulous connection with trachea; Distal oesophagus has another fistulous connection with trachea

Question 11

What is a type E OA

Answer 11

Continuity of the Oesophagus with a tracheo- oesophageal fistula (4%). Oesophagus has a continuous wall with no atresia but there is a fistula between the oesophagus and the trachea.

Question 12

What is a type F OA

Answer 12

Continuity of the oesophagus with a narrow lumen. There is no atresia but rather an oesphageal stenosis
Apart from these types other rare types have been described

Question 13

What are some known associated anomalies of oesophageal atresia

Answer 13

Known associations include VACTERL (Vertebral, Anorectal, Cardiac, Tracheo-oesophageal, Renal, and Limb) anomalies, CHARGE (Coloboma of the eye, Hean Defects, Atresia of the nasal Choanae, Retardation of Growth/ Development, Genital and /or urinary) anomalies, Downs’
Syndrome and others. This may be due to an early teratogenic event which affects a number of systems

Question 14

What is the pathophysiology of an OA

Answer 14

This depends on the type of oesophageal atresia and associated anomalies. In all oesophageal atresias with a blind ending proximal pouch there is a constant risk of aspiration of saliva, and food from the upper pouch. Where there is a distal tracheo-oesopbageal fistula as is seen in type C, there is a risk of aspiration of gastric contents into the air way through this fistula. Gaseous distension occurs in these patients as gas is passed through the fistula into the stomach and may lead to gastric dilatation, splinting of the diaphragm and respiratory compromise. Gastric perforation mayalso occur asacompli- cation of this dilatation. This influences to a large extent the position in which the baby is nursed and emphasizes the need to reduce unnecessary disturbance and crying of the baby during care. Those with a fistula alone tend to present with intermit- tent periods of aspiration leading to recurrent chest infections or asthmatic attacks

Question 15

How is an OA diagnosed

Answer 15

The diagnosis of oesophageal atresia can be made prenataly or postnataly. Prenatal diagnosis prevents aspiration, since food is avoided, and suction started as soon as the child is born . Antenatal diagnosis is done with the.aid of ultrasound which
shows polyhydramnios, an oesophageal pouch, a small stomach and delay in swallowing. This is the preferred means of making the diagnosis and significantly improves the prognosis. It has become routine in most developed countries.
Post natal diagnosis is made with a history of polyhydramnios and a history of persistent salivation soon after birth . It is at this stage that the diagnosis should be suspected. An attempt to pass a radio-opaque size 1OFrench gauge nasogastric tube into the stomach fails to go beyond 10 cm from the lips. This
confirms the diagnosis. Failure to recognize excessive salivation, leads to feeding which results in choking coughing and cyanosis soon after feeds. The diagnosis may then be confined as stated above.
Examination may show a preterm or term patient, in respiratory distress. This is usually due to an airway blocked by secretions or may be due to pneumonia. The child maybe cyanosed.The abdomen may be scaphoid in patients without a distal tracheo-oesophageal fistula but is usually distended and tympanitic in the majority of patients who have a distal tracheo-oesophageal fistula.
The child needs to be examined thoroughly for signs of
associated anomalies including cardiac, vertebral, limb, gastrointestinal and others. Common associations such as the VACTERL and CHARGE associations should be considered when examining thepatients. Cardiac anomalies in particular, influence prognosis significantly. In patients with a tracheo-oesophageal fistula alone, presentation is with a history of frequent recurrent episodes of cough and pneumonia.
In most developing countries, late presentation tends to be the norm and this significantly affects prognosis

Question 16

What are some investigations to be made in an OA

Answer 16

The most important diagnostic investigation is a plain x-ray of the chest with a radio-opaque nasogastric tube in situ. This may show the tube arrested or coiled in the upper pouch. A lateral view shows the tracheal bifurcation and its relationship with the upper pouch. The chest x-ray may also show evidence of pneumonia, cardiac anomalies and vertebral anomalies. An abdominal x-ray may show gas in the abdomen, confirm- ing a distal tracheo-oesophageal fistula or absence of gas,due to oesophageal atresia without a distal fistula. It may also show vertebral anomalies and other intestinal malformations.
An echocardiogram shows any cardiac anomaly while an abdominal ultrasound shows any renal anomalies. Barium swallow as a means of diagnosing oesophageal atresia should be avoided as much as possible due to the high risk of aspiration and must only be done if necessary in a tertiary centre with an experienced radiologist. ln the majority of cases this is not necessary.
Karyotyping may be done where chromosomal anomalies are suspected.
Other blood investigations are done in preparation for surgery

Question 17

What is the initial management for OA

Answer 17

Immediately the diagnosis is suspected, suction of the upper pouch should be instituted and breast feeding avoided. Suction, at least every I0 minutes or more should be carried out. Where a replogle tube is available and low pressure suction can be done, continuous suction may be instituted. This should be continued during transport from a peripheral to a tertiary centre and from one ward to another in the hospital while investigations are on-going. The child should be kept warm preferably in an incubator. He or she should be nursed with ahead-up tilt, to reduce the risk of aspiration of gastric contents in those with a distal tracheo-oesophageal fistula but a head-down tilt is preferable in those without a distal tracheo-oesophageal fistula.
Antibiotics and intravenous fluids should be started. Vitamin K is given if there is doubt about receipt of vitamin K soon after birth. In centres where this is available parenteral nutrition may be started if a prolonged delay in feeding is anticipated

Question 18

What is the surgical activity done for OA patients

Answer 18

The aim of surgery is to restore continuity of the oesophagus. This can be done as a primary procedure, a delayed primary procedure or a staged procedure.
Primary procedure - Thoracoromy, Division of the tracheo-oesophageal fistula and oesophago-oesophageal anastomosis soon after birth. This is the procedure of choice. It is indicated in all patients with oesophageal atresia who have a distal tracheo-oesophageal, with adequate weight, ashort gap, no other serious abnormality and a clear chest.
Patients with a double fistula with a clear chest and no other serious abnormality may also benefit from this procedure.
Delayed Primary procedure - Thoracotomy, division of a tracheoesophageal fistula and oesophago-oesophageal anastomosis after a period of preparation. This is indicated in patients with oesophageal atresia and a distal tracheo-oesophageal atresia who have a mild chest infection which must be treated adequately before surgery. It may also be indicated in patients with a wide gap after attempts to shorten the gap by various means such as dilatation have been successful.
Staged procedure- Initial Oesophagostomy, Division of tracheo-oesophageal fistula and gastrostomy followed on a later date by oesophageal replacement with the colon or stomach when the child has an adequate weight. In those without a fistula division of a fistula is not included. This is indicated in patients with oesophageal atresia with a bad chest infection, those with a long gap that cannot be bridged, those whose birth weight makes primary surgery unsafe, or those with an anomaly that makes primary surgery unsafe. The child is fed initially through the gastrostomy tube and saliva exits through the oesophagostomy to prevent aspiration until definitive surgery is done.
The H-Type fistula may be corrected by division of the listula through a cervical approach. Waterston classification was initially used to guide therapy but this has become less relevant in the developed world where antenatal diagnosis and early surgery is the norm, Spitz classification has been proposed to guide treatment in those centers.

In the developed world, with antenatal diagnosis, improvement in neonatal intensive and respiratory care, as well as parenteral nutrition, Spitz classification has become more relevant. Birth weight less than l .5 kg, and severe cardiac anomaly are the only significant prognostic factors and primary surgery is the norm. However, in the developing world, delayed presentation with chest infection is routine. Neonatal ventilatory and other respiratory support, as well as parenteral nutrition are not readily available. Waterston’s classification is thus relevant. Most patients are in group C. Staged procedures and sometimes delayed primary surgery are preferable in order to prolong survival of children under these conditions. Primary anastomosis is beneficial in a few patients in Group A who present soon after birth

Question 19

What are some postoperative complications of an OA

Answer 19

Collapse of the lungs.
Aspiration pneumonia
Necrosis of the suture line and leakage into the pleural cavity
Stenosis of the anastomosis
Recurrence of the fistula
Cyanotic or “dying” attacks which result from laryngospasm caused either by gastro-oesophageal reflux or from traheomalacia (softening of the cartilage rings of the trachea).
Skin excoriation, widening of stoma, blockage of gastrostomy rube, gastric outlet obstruction and intestinal obstruction are complications associated with gastrostomy
Stenosis of the oesophagostomy may occur

Question 20

What is the prognosis of an OA

Answer 20

Birth weight less that 1.5 kg, and severe cardiac anomalies being the only negative prognostic factors. Thosc over 1.5 kg have a survival of over 90%.
In the developing world where late presentation is the norm and neonatal ventilatory support is not available, prognosis still depends on birth weight less than 2.5 kg, the presence of chest infection which is associated with delayed presentation, as well as severe congenital anomalies. Prognosis is poor

Question 21

What is the postoperative management of OA

Answer 21

The child is nursed in an incubator and particular attention is paid to fluid therapy. Antibiotics are continued. Ryles tube must be passed with care down the oesophagus for aspiration or feeding as it may disrupt the anastomosis.
On the seventh day a barium swallow is done and if the anastomosis is intact, graduated oral fluid maybe commenced.
If there is a small leakage, oral fluid must be withheld and a feeding gastrostomy performed under local anaesthesia. If the leakage is large, an immediate thoracotomy is done and the leakage repaired; at the same time intravenous feeding or a feeding gastrostomy is instituted. The gastrostomy tube is removed when the anastomosis is fully healed and subsequent barium swallow does not demonstrate a leakage. The gastrostomy wound then heals gradually.
If the child survives surgery, there is usually no further problem until it begins to lake solid foods. There may be some dysphagia due to narrowing of the anastomotic site. This may require dilatation. However, excision of the narrowed anastomotic site may be required and a wider lumen obtained on re-anastomosis.
A point of emphasis in any regimen involving a considerable period of gastrostomy feeding with a cervical oesophagostomy is the commencement of sham feeding by mouth (which must be at the same time as the gastrostomy feed is given) thereby encouraging peristalsis. If this procedure is ignored, considerable psychological upsets occur when oral feeding is later instituted after reconstruction.
Experienced and excellent nursing care is necessary to prevent cross infection, clear excess pharyngeal mucus and change of the baby’s posture regularly

Question 22

What are the two classifications for surgery in esophageal atresia

Answer 22

Waters on classification and Spitz classification