developmental disorders of lungs, congenital anomalies of lung

1. Developmental disorders of lungs
Dr. Firoz A Hakkim
Chest Medicine

2. Introduction
Mostly congenital
Consequence of disordered organogenesis
May be diagnosed before birth or early in
postnatal life, so corrective surgery may be
applied

3. Period Stage Duration Charecteristics
Embryonic Embryonic 4-7 wks Start of
organogenesis,
formation of major
airway
Fetal Pseudoglandular 5-17 wk Formation of
bronchial tree &
large parts of
prospective
respiratory
parenchyma , birth
of acinus
Canalicular 16-26 wk Completion of
conducting airway ,
epithelial
differentiation. First
air blood barrier,
appearance of
surfactant

4. Sacular 24- term Expansion of
airway
Postnatal Alveolar 36 wks- preterm (1-
2 yrs)
Alveorazation
By formation of
secondary septa
(septation)
Microvascular
maturation
0-3 yrs Remodelling and
maturation of
interalveolar septa
and of capillary bed
Normal growth 2nd yr - adulthood Normal growth of
lung

7. Classification
Tracheobronchial
anomalies
Anomalies involving
lung parenchyma
Anomalies of
pulmonary
vasculature
•Tracheal agenesis
•Tracheo – oesophageal
fistula
•Tracheal stenosis
•Tracheal narrowing due
to extrinsic pressure
•Tracheomalacia
•Tracheobronchomegaly
•Abnormal pattern of
bronchial branching
•Bronchial atresia
•Bronchogenic cyst
•Congenital
adenomatoid
malformation of lung
•Agenesis and
hypoplasia of lung
•Congenital
abnormalities of
lobulation
•Lung sequestration
•Absent pulmonary
artery trunk
•Absent unilateral
pulmonary artery
•Pulmonary artery
stenosis
•Anomalous orgin of
left pulmonary artery
•Anamalous systemic
pulmonary perfusion
•Anamalous pulmonary
venous drainage
(scimitar syndrome)
•Pulmonary
arteriovenous
malformation and
telangiectasia

8. Tracheobronchial anomalies
• Lower respiratory tract shares its embryological
origin with primitive foregut, arising from its ventral
surface in 4th wk of IUL as laryngotracheal bud or
respiratory primordial pouch
• Subsequent development of tracheobronchial tree
and oesophagus proceeds concurrently
• Congenital abnormality of one affects the other
• Developmental errors cannot arise after 16th wk of
IUL , since by this time its formation would have
been complete

9. Tracheal agenesis/ aplasia
• Absence of growth in trachea or in part of it
• Male: female :: 2:1
• 3 anatomical patterns
• Type 1- agenesis of proximal trachea. Distal trachea
is present, connected to oesophagus by fistulous
communication . 20 % cases
• Type 2 – main bronchi join in midline , communicate
with oesophagus by single fistula, 60% cases .most
common
• Type 3 – left and right main bronchi join oesophagus
20% cases

11. Tracheal agenesis/ aplasia
• Infant may survive for a period
• Early diagnosis may allow temporary
measures to sustain respiration , later
reconstructive surgery

12. Tracheo – oesophageal fistula
• H type tracheo –oesophageal fistula, both
trachea and oesophagus remain patent
• Maybe undetected until adult life
• Aspiration of oesophageal content into
airway may cause choking, with cough and
cyanotic episodes after feeding
• Passage of air through fistula into
oesophagus may cause abdominal distention
• Recurrent pneumonia is common

15. Tracheal stenosis
• Can be diffuse 30%, segmental 50%, or
funnel like 20%
• Associated with tracheo – oesophageal
fistulae, and accesory bronchi arising
from trachea
• Presents in infancy with stridor,
respiratory insufficiency
• Surgical treatment, plastic tracheal
reconstruction

18. Tracheal narrowing due to extrinsic
pressure
• Results from close proximity of unusually
large or abnormally placed vessels, that have
arisen as faulty devpt. of primitive system of
branchial arches
• Double aortic arch 47%, right aortic arch with
left ligamentum arteriosum 20%, retro
oesophageal right subclavian artery 14%,
anomalous innominate artery 11%,
anomalous left carotid artery 4%,
retrotracheal or sling left pulmonary artery
3%, right aortic arch with aberrant left
subclavian artery 1%

19. Double aortic arch

20. Sling left
pulmonary artery

21. Tracheomalacia
• Excessive weakness and collapsibility
of tracheal walls as a result of
abnormally soft or pliable cartilages
• Result of deficiency cartilge in a short
segment of trachea
• Result of prolonged ET intubation
• Rare systemic disorder like relapsing
poluchondritis
• Severe cases surgical intervention and
tracheal splinting procedures

23. Tracheobronchomegaly
• Charecterised by unusual widening of
trachea and main bronchi
• Inherited as an autosomal recessive
disorder in assoctn with EDS
• There is atrophic defect of the
connective tissue of trachea and main
bronchi
• Confirmed by ct
• c/f = wheezing dyspnoea, resp distress
during feeding, rec lrti, stridor, cyanosis

24. Tracheobronchomegaly

25. Abnormal pattern of bronchial
branching
Most common anomaly is a
supernumerary rt upper lobe bronchus
May arise from trachea(0.9%) or rt main
bronchus(0.4%)
Most common segmental anomaly is a
double stem apical lower lobe
segmental bronchus (7%)- r >>lt

26. Supernumerary bronchus

27. • Bronchial isomerism – rare devpmt
anomaly in which normal pattern of
bronchial branching , in either rt or left
lung is mirrored in the contralateral lung
resulting in so called b/l rt or lt lung

29. Bronchial atresia
• Apicoposterior segment of lt upper lobe gets sealed from the
proximal airways to which it may remain attached by a thin
fibrous strand, so secretions get accumulated in the sealed
portion, which gets distended to form cystic space or mucocoel.
• Ventilation maintained by alveolar pores of kohn
• Pts majority asyptomatic.
Xray= mucocoel appears as a coin lesion and the part of lung
distal to it appears hypertransluscent ( air trapping)
Ct is confirmatory
Risk of infn is low
Surgical excision

30. Mucocoel, ( coin
lesion)

31. Bronchogenic cyst
• 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

32. • Classified as central and periphery
• Central >peripheral
• Cysts may be single , multiple, or b/l lungs
• 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

33. • Xray and ct diagnostic
• Xray = well circumscribed , rounded
homogenous opacity , close to major
airway or in the periphery
• Surgical excision of the cyst

34. Bronchogenic cyst