Congenital Disorders of Lung

Dr. Rikin Hasnani

• Development of lung• Tracheobronchial abnormalities • Parrenchymal abnormalities

Development The respiratory system is an outgrowth of the ventral wall of

the foregut.• The epithelium of the larynx, trachea, bronchi, and alveoli

originates in the endoderm. • The cartilaginous, muscular, and connective tissue

components arise in the mesoderm. • In the fourth week of development, the tracheoesophageal

septum separates the trachea from the foregut, into the lung bud anteriorly and the esophagus posteriorly.

• Contact between the two is maintained through the larynx, which is formed by tissue of the fourth and sixth pharyngeal arches

• ◦The lung bud develops into two main bronchi: the right forms three secondary bronchi and three lobes; the left forms two secondary bronchi and two lobes.

Development of lung

TRACHEOBRONCHIAL ABNORMALITIES

• ◦TRACHEAL AGENESIS• ◦TRACHEAL STENOSIS• ◦TRACHEOMALACIA• ◦TRACHEO-OESOPHAGEAL FISTULA• ◦BRONCHIAL ATRESIA

Tracheal Agenesis• Tracheal agenesis is a rare and in most cases lethal

anomaly. It may be suspected because of lack of audible crying, and is often diagnosed right after birth with water soluble contrast medium injected into the oesophagus.

• Type 1: Absent upper trachea, & lower trachea connecting to the oesophagus.

• Type2: Common bronchus connecting right and left main bronchi to the oesophagus with absent trachea.

• Type 3: Right and left main bronchi arising independently from the oesophagus

Tracheal Stenosis

• It is narrowing of Trachea.• It is diffuse in 30% cases the parsmembranacea

being absent so that the trachea is encircled by napkin ring cartilage.

• Segmental stenosis is more common and occurs in equal frequency in upper middle and lower trachea.

• In 20% of cases the stenosis is carrot or funnel like and is associated with “Sling Left Artery Syndrome”

Tracheomalacia

• Tracheomalacia is excessive weakness and collapsibility of the tracheal wall as a result of abnormally soft or pliable cartilage

• Primary: by congenital immaturity of the tracheal cartilage. • Secondary: previously normal cartilage undergoes

degeneration. • Congenital (primary): Vascular ring, Tracheo-Oesophageal

Fistulas• Acquired : prolonged Intubation , relapsing polychondritis

• Patient presents in childhood with expiratory airflow obstruction and apnoeic episodes.

• In severe cases aortopexy and various trachealsplinting procedures may be necessary.

Tracheobronchomegaly

• AKA Mounier-Kuhn Syndrome• This is characterized by unusual width of the

trachea and main bronchi• It is diagnose when diameter of trachea , right

main bronchus or left main bronchus size greater than 3.0 cm; 2.4cm ; 2.3 cm respectively.

• It is often complicated by recurrent LRTI and Bronchiectasis due to ineffectiveness of cough.

• Cough has loud booming quality.

Mounier-Kuhn Syndrome

Tracheo-oesophageal Fistula

•Type A: Corresponds to pure esophageal atresia without fistula.

•Type B: is esophageal atresia with fistula between the proximal pouch and the trachea.

•Type C: is esophageal atresia and fistula from the trachea or the main bronchus to the distal esophageal segment. (most common)

•Type D: is esophageal atresia with both proximal and distal fistulas

•Type E: is tracheoesophageal fistula without atresia

• ◦In types A and B, there is complete absence of gas in the stomach and intestinal tract;

• ◦In types C and D, the gastrointestinal tract usually appears distended with air.

• ◦Three-dimensional CT and virtual bronchoscopy allow accurate location of the site of fistula and can show the length of gap between the proximal and distal esophageal pouches.

Bronchial Atresia

• It probably arises as a result of a developmental interruption of normal bronchial continuity in which length of a bronchus becomes sealed off from the larger proximal airways .

• Usually apicoposterior segmental bronchus of left upper lobe is affected.

• The sealed off bronchus becomes distended by bronchial secretions , resulting in the formation of a cystic space or mucocele

• Majority of patients are asymptomatic and the diagnosis of bronchial atresia is an accidental finding.

• Chest radiograph shows the mucocele as a coin lesion and part of the lung distal to it appears hyperlucent as a result of collateral air trapping.

Bronchogenic Cyst

• It arises as a result of abnormal budding of tracheobronchial tree during the course of its development between 26th day and 16th week of intrauterine life therafter developing seperately to produce a cystic structure.

• They may be central or peripheral.

Development of lung

• This patients are mostly asymptomatic• When symptoms do occur, they result either

from mass affect on adjacent structure or due to infection.

• X ray shows a well circumscribed , rounded, homogenous opacity either in mediastenum close to a major airway or in the lung periphery, if a fistulous tract is present an air fluid level may be seen.

• Elective surgical resection is treatment of choice for bronchogenic cyst.

Infected bronchogenic cyst

PARRENCHYMAL ABNORMALITIES

• AGENESIS AND HYPOPLASIA OF LUNG• PULMONARY SEQUESTRATION

AGENESIS AND HYPOPLASIA OF LUNG

• Agenesis means complete absence and hypoplasia means underdevelopment of lung.

• Complete bilateral agenesis –incompatible with life.

• Unilateral agensis is more common on left side. • Cause is unknown, however condition that

decreases intrathorasic space, especially congenital diaphragmatic hernia may cause unilateral lung agenesis.

• Bilateral pulmonary hypoplasia is associated with the presence of oligohydramnios caused by renal tract anomalies or amniotic leak syndrome.

• PROM and maternal use of ACE inhibitors are other causes of pulmonary hypoplasia.

Left Lung Hypoplasia

Lung Sequesterations

• It is characterized by formation of an island of abnormal unventilated lung tissue that has no normal communication with the bronchial system and derives its blood supply from systemic , rather than pulmonary circulation.

• This are of two types• 1) intralobar • 2) extralobar

Feature Intralobar Extralobar

Frequency More common Less common

Male:female 1:1 4:1

Most commmon site Within Posterior basal segment

Between lower lobe and diaphragm

Side of thorax 60% left sided 90% left sided

Arterial supply 70% thorasic aorta 45% thorasiv aorta

Venous drainage Usually pulmonary vein Often systemic vein

Diagnosed in neonates Rarely Commonly

Other cong. defects Uncommon Frequent

Clinical features

• Extralobar are frequently diagnosed in 1st year of life.

• Intralobar may present with LRTI, recurrent pneumonic episode or massive hemoptysis.

• Extralobar sequestraaions are less liable to infections

Radiological features

Treatment

• Symptomatic pulmonary sequestration should be resected

• Any infection should be treated with appropriate antibiotics.

• Intralobar sequestrations requires segmental resection or lobectomy.

• Extralobar sequestrations may be resected without disturbing normal lung.

Thank You