**2.7 Pathophysiology of oesophageal atresia**

The discontinuation of the oesophageal lumen prevents swallowed amniotic fluid by the foetus from reaching the stomach and hence the intestine. In view of this, the physiological control of amniotic fluid volume by the foetus, through swallowing and absorption, is impaired, leading to polyhydramnios. This would in turn lead to premature rupture of membrane, umbilical cord prolapse and premature delivery.


**Table 2.**

*Chromosomal abnormalities associated with oesophageal atresia.*


#### **Table 3.**

*Single gene mutations associated with oesophageal atresia.*

Postnatally, the neonate is not able to swallow saliva and food. This leads to accumulation of saliva and food in the upper oesophageal segment (pouch). The accumulated saliva and food then spill over into the lungs through the larynx and trachea. Patients are therefore prone to the development of aspiration pneumonia. Patients with distal tracheo-oesophageal fistula also tend to aspirate gastric secretions into the lungs, especially if lying in a head-down position.

The distal tracheo-oesophageal fistula also allows air to escape from the trachea to the stomach and hence the intestines. Consequently, patients can develop gross distention of the stomach and intestine, especially if patient is resuscitated using an Ambu bag. The distended stomach can then splint the diaphragm, impairing diaphragmatic excursion and thereby causing respiratory distress. The distended stomach can also rupture leading to chemical peritonitis.

In patients with delayed diagnosis, the constant regurgitation of swallowed food leads to malnutrition. Such patients tend to have poor surgical outcome and overall survival.

Associated congenital anomalies, especially severe cardiac and renal anomalies, also affect management and survival of patients. Low birth weight that may result from premature delivery owing to polyhydramnios also tends to affect management and survival.

### **2.8 Clinical presentation**

Oesophageal atresia may be detected prenatally or postnatally.

#### *2.8.1 Prenatal presentation and diagnosis*

Prenatal diagnosis helps in planning of delivery and possible prenatal referral to centres that have the facilities to manage such patients.

Oesophageal atresia should be suspected prenatally in patients with evidence of polyhydramnios. Polyhydramnios will present with symphysio-fundal height


**55**

*Oesophageal Atresia: Drowning a Child in His/Her Own Saliva*

of more than the expected for gestational age. This is confirmed with antenatal

Antenatal ultrasonographic features of polyhydramnios, a small stomach, a distended upper oesophageal pouch and abnormal swallowing should raise the

Postnatally, patients with oesophageal atresia present with drooling of saliva (excessive salivation). A history of antenatal polyhydramnios gives more credence to the diagnosis of oesophageal atresia. Delayed diagnosis leads to aspiration of saliva from the upper oesophageal pouch, causing aspiration pneumonia with cough, cyanosis and fever. Feeding leads to worsening of the aspiration pneumonia. Hence, early detection and avoidance of oral feeds helps to promote good outcome

Patients with distal tracheo-oesophageal fistula are also at risk of aspiration of gastric secretions into the lungs. In addition, swallowed air passes through the distal tracheo-oesophageal fistula into the stomach. This can lead to gross gastric distention, especially following Ambu bagging, resulting in diaphragmatic splinting and sometimes gastric rupture. They may thus present with respiratory distress, gross

Patients with tracheo-oesophageal fistula without oesophageal atresia are usually diagnosed late. They present with recurrent cough associated with feeding and

Other symptoms would depend on associated congenital anomalies. Patients with cardiac anomalies may present with cyanosis. Patients with renal agenesis will

During history taking, one should seek for a maternal history of uncontrolled diabetes mellitus and the use of drugs such as oral contraceptives, antithyroid drugs (carbimazole and methimazole) and thalidomide. These are risk factors for

The history of the maturity and weight of the baby at birth are also important

The principles of physical examination of a patient with suspected oesophageal atresia are to confirm the diagnosis, assess for aspiration pneumonia and evaluate

To confirm the diagnosis, a stiff radiopaque 10-gauge French catheter is passed through the mouth into the oesophagus. The tube is not passed through the nose because it may traumatize the nasal passages. The diagnosis of oesophageal atresia is heightened if the tube fails to reach the stomach by getting arrested in the proximal oesophageal pouch at about 10 cm from the alveolar margin. A soft and smaller tube may coil in the upper oesophageal pouch, giving an impression of reaching the stomach. The secretions sucked through the tube can be tested with litmus paper to differentiate between saliva (basic) in the upper oesophageal pouch and gastric

The presence of fever, respiratory distress, reduced air entry in the lungs (especially on the right side) and crepitations in the lungs are an indication of aspiration pneumonia. However, patients in heart failure will have similar chest findings, and

ultrasonography with amniotic fluid index (AFI) of more than 24 cm.

*DOI: http://dx.doi.org/10.5772/intechopen.84525*

suspicion of oesophageal atresia [28–31].

*2.8.2 Postnatal presentation and diagnosis*

abdominal distention and sometimes peritonitis.

recurrent episodes of pneumonia.

have a history of anuria.

oesophageal atresia.

secretions (acidic).

*2.8.2.2 Physical examination*

for associated congenital anomalies.

considerations.

*2.8.2.1 History*

of patients.

**Table 4.**

*Common associated anomalies in non-syndromic oesophageal atresia.*

#### *Oesophageal Atresia: Drowning a Child in His/Her Own Saliva DOI: http://dx.doi.org/10.5772/intechopen.84525*

of more than the expected for gestational age. This is confirmed with antenatal ultrasonography with amniotic fluid index (AFI) of more than 24 cm.

Antenatal ultrasonographic features of polyhydramnios, a small stomach, a distended upper oesophageal pouch and abnormal swallowing should raise the suspicion of oesophageal atresia [28–31].

## *2.8.2 Postnatal presentation and diagnosis*
