Congenital Abnormalities of the Chest Wall, Lung and Diaphragm

Question 1

A 1-week-old baby is bought into the emergency department by his mother.

She says he has been coughing and producing excess snot and drool. He chokes during feeds and develops a blue tinge to his skin (cyanosis) while struggling to breath (respiratory distress).

Antenatally, scans discovered a presentation of polyhydramnios.
What do we think might be the problem and what could be done to confirm the diagnosis?

Answer 1

• Possible TOF
• TEST 1 - Pass NGT into stomach. If it curls back - suggests oesophageal atresia
• TEST 2 - CXR/AXR - no gastric bubble = oesophageal atresia with no TOF. Gastric bubble present = oesophageal atresia with distal TOF.

Question 2

Describe the different types of TOF

Answer 2

• Proximal oesophageal atresia - distal oseophagus forms fistula with trachea
• Isolated oesophageal atresia
• H-type TOF without atresia
• Proximal oesophagus to trachea fistula - DISTAL OESOPHAGEAL ATRESIA
• Proximal/distal oesophagus to trachea fistula

Question 3

How can TOF be classified?

Answer 3

• Syndromic or non-syndromic/isolated

Question 4

Describe an example of syndromic TOF. CONDITION 1

Answer 4

CONDITION 1 - VACTERL Association
- Vertebral anomalies, anal atresia, cardiac defects, TOF, esophageal atresia, renal abnormalities
- Cause unclear
- Occur frequently together

Question 5

Describe an example of syndromic TOF. CONDITION 2

Answer 5

CONDITION - CHARGE Syndrome (CHD7)
- Coloboma, heart defects, choanae atresia, renal/genital/ear abnormalities

Question 6

What factors are involved in non-syndromic TOF?

Answer 6

• Causal genetic aberration in 11-12% of patients
• Variable feature in several known single gene disorders
• Seen in patients with specific recurrent copy number variations/structural chromosomal aberrations
• EXTERNAL - maternal diabetes/drug abuse/smoking and alcohol exposure

Question 7

Describe the management of TOF.

Answer 7

• Regular suctioning
• ECG
• IV fluids and antibiotics
• Raise head of bed
• Early surgical repair

Question 8

An anomaly scan (20 week scan) indicates the following:
* Polyhydramnios
* Abnormal cardiac axis
* Lack of normal stomach bubble
* Absent bowel movements
* Peristaltic bowel movements in the chest
* Stomach and small bowel at same transverse level of heart
WHAT DO THESE FINDINGS SUGGEST?

Answer 8

Left sided congenital diaphragmatic hernia

Question 9

Describe formation of the primitive body cavity.

Answer 9

• Ectoderm forms neural tube/external surface
• Endoderm forms gut tube
• Lateral plate mesoderm splits to form primitive body cavity
• Visceral mesoderm forms outer membranous layer of organs
• Parietal mesoderm lines cavity to become parietal peritoneum/membrane/pleura

Question 10

What are the 4 structures from which diaphragmatic development occurs?

Answer 10

• Septum transversum
• Pleuroperitoneal folds
• Dorsal oesophageal mesentery
• Body wall musculature

Question 11

What occurs in the septum transversum?

Answer 11

• Thick plate of visceral lateral plate mesoderm - partially separates thoracic and abdominal cavities
• Becomes future central tendon

Question 12

What occurs in the pleuroperitoneal folds?

Answer 12

• Thoracic, abdominal cavities still in connection via pericardioperitoneal canals
• Grow towards each other and septum transversum to close connection off

Question 13

What occurs in the dorsal oesophageal mesentery?

Answer 13

• Fuses with septum transversum and folds
• Thoracic cavity closed off from abdominal cavity
• Future crura of diaphragm

Question 14

What occurs in the body wall musculature?

Answer 14

• Myoblasts originating from C3, 4 and 5 somites penetrate folds
• Forms muscular part of diaphragm

Question 15

How does separation of the pleural and pericardial cavities?

Answer 15

• Separated by pleuropericardial folds

Question 16

Describe congenital diaphragmatic hernia.

Answer 16

• Failure of peritoneal and pleural/pericardial cavities to close
• Abdominal viscera can enter thoracic cavity
• Can compress lungs - cause pulmonary hypertension
• Occurs in 1 in 2000 newborns, with 85-95% on left side

Question 17

Which of the 4 structures that form the diaphragm most commonly failt to cause congenital diaphragmatic hernias?

Answer 17

Pleuroperitoneal membranes

Question 18

When is CDH diagnosed and what is it usually associated with?

Answer 18

• Associated with high mortality, especially if diagnosed in first trimester of pregnancy
• Associated with other structural anomalies/ single gene mutations/ chromosome deletions
• Most cases are diagnosed at the anomaly scan – confirmation with fetal MRI
• Postnatal diagnosis is via CXR
• Prognosis for right-sided CDH is worse / Prognosis is related to about of lung tissue in fetal chest

Question 19

How can CDH be fixed?

Answer 19

• Fetal endoscopic tracheal occlusion
• Antenatal steroids
• Intubation and surgery postnatally

Question 20

Describe an example of a congenital lung malformation. CONDITION 1

Answer 20

PULMONARY HYPOPLASIA
- Lungs don’t develop properly
- Usually secondary to CDH and pleural effusions
- Treatment aimed at underlying cause

Question 21

Describe an example of a congenital lung malformation. CONDITION 2

Answer 21

PULMONARY SEQUESTRATION
- Non-functional lung tissue - no connection to pulmonary tree
- Cough, recurrent pneumonia
- Treatment - surgical resection

Question 22

Describe an example of a congenital lung malformation. CONDITION 3

Answer 22

CPAM (CONGENITAL PULMONARY AIRWAY MALFORMATION)
- Multicystic mass of lung tissue due to abnormal branching morphogenesis
- Present with cough, recurrent pneumonia, respiratory failure
- Treatment - surgical

Question 23

Describe an example of a congenital lung malformation. CONDITION 4

Answer 23

CONGENITAL LOBAR EMPHYSEMA
- Developmental deficiency of bronchial cartilage/stenosis
- Air trapping - hyperexpansion of lung lobe
- Can progress to respiratory distress/recurrent pneumonia
- Treatment - surgical resection

Question 24

Give examples of abnormalities of the chest wall. CONDITION 1

Answer 24

PECTUS EXCAVATUM
- Congenital or acquired
- Isolated anomaly or associated with other syndromes
- Familial predisposition

Question 25

Give examples of abnormalities of the chest wall. CONDITION 2

Answer 25

POLAND SYNDROME
- Congenital
- Unilateral absence of chest wall muscles
- Ipsilateral short, webbed fingers

Question 26

• What can most chest wall abnormalities lead to?
• What can surgical repair of these abnormalities result in?

Answer 26

• Restrictive lung diseases
• Rarely results in significant improvement in lung growth and function. May be necessary to prevent further deterioration.