Developmental anomalies of lung

1. DEVELOPMENTAL DISORDERS
OF LUNGS
DR AMBIKA GUPTA
JRII PULMONARY MEDICINE

2. DEVELOPMENT OF LUNG
• Upper part of respiratory system
– Extends from nose to larynx
– Develops from the Pharyngeal Apparatus which is
a part of Head & Neck
Lower Part of Respiratory System
• Extends below the Larynx up to lung alveoli
• This part develops From the Foregut

3. DEVELOPMENT OF LUNG
• Respiratory System is derived from Second
Part of Foregut
• a. It begins to develop in the beginning of the
fourth week (day 22)
• b. It begins as a laryngo- tracheal groove on
the ventral aspect of the foregut, which
deepens and forms a respiratory diverticulum.
• c. Separates from the oesophagus

4. A
 The respiratory diverticulum's bifurcates into right and
left bronchial buds on day 26-28.
 Asymmetric branching of buds occurs during the
following 2 weeks to form secondary bronchi:
 3 on the right and 2 on the left forming the main
divisions of the bronchial tree.
 The lung bud and its subsequent branches are of
endodermal origin.
 They give rise to the epithelium lining all the respiratory
passages, the alveoli and the associated glands.
 The surrounding mesoderm, the splanchnopleure,
gives rise to all the supporting structures: the
connective tissue, cartilage, muscle and blood vessels.

5. DEVELOPMENT OF LUNG

6. DEVELOPMENTAL DISORDERS OF
LUNGS

7. Tracheal agenesis
• Rare.
• Commonly associated with maternal polyhydramnios .
• Presentation is immediate and acute with severe respiratory
distress, absent cry and inability to intubate the airway. And
often diagnosed right after birth with water soluble contrast
medium injected into the oesophagus.
• There are three main form
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 of tracheal agenesis:

9. Tracheal Stenosis
• It is narrowing of Trachea. Can be diffuse 30%, segmental 50%, or
funnel like 20%. • 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 pulmonary Artery Syndrome”
• In diffuse cases the parsmembranacea being absent so that the
trachea is encircled by napkin ring cartilage.
• Associated with tracheo – oesophageal fistulae, and accessory
bronchi arising from trachea.
• Presents in infancy with biphasic stridor, respiratory insufficiency.
• CT is useful in assessing the anatomy and has the added advantage
of angiographic capabilities.
• MRI and bronchoscopy
• Surgical treatment, plastic tracheal reconstruction

12. Tracheomalacia
• Softening of the tracheal wall, due to cartilaginous abnormalities.
• Primary: (Congenital )due to Vascular ring, Tracheo- Oesophageal
Fistulas.
• Secondary Commonest type due to tracheostomy, Chronic
inflammation(associated with cystic fibrosis, recurrent aspiration,
immuno-deficiency) relapsing polychondritis.
• Extrinsic compression (vascular rings, slings or aberrancy) and
Neoplasia
• Causes expiratory wheeze and apnoeic episodes.
• Fluoroscopy shows an exaggerated decrease in the sagital width of
the trachea during expiration.
• Dynamic CT can be useful to assess the cross- sectional anatomy
and compliance of the trachea.
• In severe cases aortopexy and various tracheal splinting procedures
may be necessary.

14. Tracheobronchomegaly
• AKA Mounier-Kuhn Syndrome
• This is characterized by unusual width of the trachea
and main bronchi.
• There is atrophic defect of the connective tissue of
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.
• Inherited as an AR disorder in assoctn with EDS.
• Confirmed by CT
• c/f = Cough has loud booming quality, wheezing
dyspnoea, resp distress during feeding, rec LRTI lead
to bronchiectasis, stridor, cyanosis.

16. Tracheo-oesophageal fistula (TOF)
• Majority of cases are associated with the presence of oesophageal
atresia.
• 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 H type is tracheoesophageal fistula without atresia ,Maybe
undetected until adult life
• 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.
• C/F May present with choking, cyanosis, coughing at the time of
feeding.
• 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

18. 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
• Ventilation maintained by alveolar pores of kohn
• 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.
• CT is confirmatory Risk of infn is low rarely need Surgical
excision

20. Bronchogenic cysts
• Result of abnormal budding of tracheo bronchial tree during the course
of devpt. b/w 26 th day and 16 th wk of IUL.
• So the tracheal and bronchial bud gets separated from its parent,
thereafter developing into a cystic structure.
• M>>f usually do not communicate with the tracheobronchial tree
• Classified as Central >peripheral
• Cysts may be single , multiple, or b/l lungs
• Carinal location is most common.
• Ectopic site = pericardium, diaphragm, vertebral column
• Infected cyst may have fluid level
• c/f = presure effect on trachea cause dyspnoea , cough and stridor, on
oesophagus dysphagia
• Repeated resp. Tract infection
• Complication – haemoptysis, pneumothorax
• Xray and ct diagnostic well circumscribed , rounded homogenous
opacity , close to major airway or in the periphery.
• Elective surgical resection is treatment of choice for bronchogenic
cyst.

24. Tracheal Bronchus
• Anomalous bronchus usually exits the right lateral wall of the
trachea less than 2 cm above the major carina and can supply
the entire upper lobe or its apical segment. Tracheal
bronchus ( Pig bronchus) • Incidence is 1 %
• If the anatomic upper-lobe bronchus is missing a single
branch, the tracheal bronchus is defined as displaced (more
common).
• If the right upper-lobe bronchus has a normal trifurcation
into apical, posterior, and anterior segmental bronchi, the
tracheal bronchus is defined as supernumerary.
• If they end in aerated or bronchiectatic lung tissue, they are
termed apical accessory lungs or tracheal lobes.
• Bronchiectasis, focal emphysema, and cystic lung
malformations may coexist.
• CT may show a small area of hypoattenuation arising directly
from the trachea.

27. CCAM
• Hamartomatous proliferation of terminal bronchioles
• Composed of both solid and cystic tissue.
• Malformations are classified on the basis of clinical,
radiographic and histological features: • Type 1,2 and 3

30. PULMONARY UNDER DEVELOPMENT
• Agenesis is complete absence of a lung or lobe with
absent bronchi
• Aplasia is absence of lung tissue but the presence
of a rudimentary bronchus
• Hypoplasia is the presence of both bronchi and
alveoli in an underdeveloped lobe
• Lung agenesis • Recognizable with a small opaque
hemithorax, displacement of mediastinal structures
towards that side. • Bronchography or
bronchoscopy confirms the absent main stem
bronchus • Angiography shows no pulmonary or
bronchial arterial circulation.

33. AZYGOS LOBE
• An azygos lobe is created when a laterally
displaced azygos vein creates a deep pleural
fissure into the apical segment of the right
upper lobe during embryological
development.
• It is a normal anatomic variant of the right
upper lobe due to invagination of the azygos
vein and pleura during development in the
fetus. It is not a true accessory lobe as it does
not have its own bronchus.

35. Pulmonary sequestration
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.

38. 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.

39. Congenital lobar over inflation/emphysema
• Characterised by progressive over distension
of a lobe
• Aetiology is unknown in 50% of cases
• Male to female ratio is 3:1
• Associated anomalies include the patent
ductus arteriosus, ventricular septal defect
and tetralogy of Fallot
• The upper lobes, or right middle lobe, are
commonly involved.

45. Pulmonary arteriovenous malformations
• Congenital or acquired.
• The acquired connections arc called pulmonary
fistulas.
• Congenital arteriovenous malformations are
abnormal communications between pulmonary
arteries and veins
• No intervening capillary bed and are often
clinically silent,
• 60% are in the lower lobes
• Typical appearances are of a well-defined
pulmonary mass which is often lobulated.

47. OTHERS
• DIAPHRAGMATIC ABNORMALITIES • Hernia •
Eventeration • Agenesis
• CYSTIC FIBROSIS • Autosomal recessive trait •
Prevalence of approximately 1 in 2500. •
Chronic respiratory illness
• Enteric cysts
• Neuroenteric cysts

48. Conclusions
• Congenital lung abnormalities include a wide
spectrum of conditions and are an important
cause of morbidity and mortality in infants and
children.
• Lung abnormalities are being detected more
frequently at routine high-resolution prenatal
ultrasonography.
• Recognizing the antenatal and postnatal imaging
features of these abnormalities is necessary for
optimal prenatal counseling and appropriate peri-
and postnatal management.

49. REFERENCES
• CROFTON AND DOUGLAS’S RESPIRATORY
DISESASES
• FISHMANS TEXTBOOK.