intrauterine lung function
source of amniotic fluid
15 ml /Kg BW
Affected by physical factors
Lung growth
Affected by hormonal factors
Lung maturation
Type 2 pneumocytes appear during
24-26 weeks
Stimulates Maturation
glucocorticoids, ACTH Thyroid hormones, TR EGF heroin Aminophyline, cAMP Interferon Estrogens
Inhibits Maturation
Diabetes (insuin,hyperglycemia, butyric acid) Testosterone TGF-B Barbiturates Prolactin
Formation of the airways begins at
4 weeks AOG
Differentiation begins at
16th week
Surfactant synthesis begins at
24-26 weeks
Embryonic phase
3-6 weeks Laryngotracheal groove Fibroblast growth factor tracheoesophageal septum tracheal bud
Pseudoglandular phase
6-16 weeks
resembles endocrine gland
all major lung elements have appeared
Respiration is not possible during this phase
Canalicular phase
16-26 weeks
Lumina of bronchi enlarge and lung tissue becomes highly vascularized
Respiration is possible
Terminal Saccular phase
26-36 weeks
blood air barrier is established
Type 1 and type 2
Alveolar Phase
Birth to 8 years old
True alveoli appear as indentations
Structurally and functionally well-differentiated
Characteristics of a mature alveolus
- connected to alveolar duct
- Lined with type 1 cells in intimate contact with cap
- Each capillary exposed to 2 alveoli
- contains surfactant
- Has interconnections with adjacent alveoli
Two stages of post natal lung growth
Increase in number until 2-8 years old
Increaselumen and size
Pulmonary agenesis
Tracheal or laryngeal agenesis or stenosis
EMBRYONIC
bronchial malformation
Ectopic lobes
AV malformation
Congenital lobar cysts
Tracheo or broncho-malacia
Cystic adenomatoid malformatiion Pulmonary sequestration lung hypoplasia lung cysts congenital pulmonary lymphagiectasia congenital diagphragmatic hernia
Pseudoglandular
Lung hypoplasia
Respiratory distress syndrome
Acinar dysplasia
Canalicular
Pulmonary hypoplasia
RDS
Acinar dysplasia
Alveolar capillary dysplasia
Saccular/alveolar
What syndrome is associated with Laryngeal or tracheal atresia
FRASER syndrome
Most common congenital anomaly of the upper airway
Laryngomalacia
Laryngomalacia
Dynamic anomaly of the supraglottis
Omega shape
Unilateral VCP
Peripheral nerve
L>R
Aspiration, Coughing, choking
Bilateral VCP
CNS
High pitched inspiratory stridor
Phonatory sound
Inspiratory cry
Benign vascular tumor with rapid growth phase for 12 to 18 months followed by involution.
L>R
Subglottic hemangioma
Diagnosis for Subglottic hemangioma
Endoscopy ; assymetric compressble bluish mass
Bilateral Pulmonary Agenesis
Rare malformation
May occur in anencephaly
Unilateral Pulmonary Agenesis
More common
Absence of carina and trachea
Mortality R> L
Lung larger than normal
Pulmonary apalsia
Absent lung Most common variant Unilateral Infections Absence of distal lung
Causes of bilateral congenital small lungs
Lack of space
Abnormal vascular supply
Neuromuscular disease
Causes of bilateral congenital small lungs due to extrapulmonary mechanical factors
Abnormal thoracic contents
Thoracic compression from below
Thoracic compression from the sides
Closed epithelium lined sacs developing abnormally, more common cysts in infancy
50% located in mediastinum close to carina
single unilocular R?L
Foregut (Bronchogenic cysts)
Cystic CTM
Spectrum of vasriably sized cysts with differing histology
congenital cystic adenomatoid malformation
Stocker Classification: Incompatible with life
TYPE O Acinar dysplasia bronchial
Stocker classification: Most common, best prognosis, one part of one lobe, PSCCE, Multiloculated
TYPE 1 Bronchial or bronchiolar
Stocker classification: 2nd most common, infection in later childhood, overgrowth of dilated bronchiolar structures separated by alveolar tissue
Type 2 Bronchiolar
Stocker Classification: Male infants, Whole lobe, appear solid, Absent pulmonary arteries
Type 3 Bronchiolar or alveolar duct
Stocker Classification: rare, peripheral thin-walled cysts, multiloculated, cystic spaces lined by alveolar type 1 or type 2 cells, intervening stroma are thin and comprise loose mesenchymal tissue
Type 4 Peripheral
Pulmonary tissue that is isolated from normal functioning and is fed by systemic arteries
Pulmonary sequestration
-pulmanry tissue is cystic
treatment for pulmonary sequestration
surgery
Intrapulmonary sequestration
Posterior basal segment of left lower lobe
Encricled by viscera
Rest of lobe is normal
Systemic drainage
Extrapulmonary sequestration
Beneath the left lower lobe 15% abdominal M>F systemic arteries are small Pulmonary drainage
Deficiency of bronchial cartilage leading to ianpropriate collapse of the airway and trapping of the air
COngenital large hypolucent lobe (congenital lobar exphysema)
Most common : Left upper lobe 42%
Incomplete mesodermal separation of the primitive foregut
Tacheoesophageal Fistula/esophageal atresia
plain radiograph of TEF/EA
tube coiled in the upper pouch
Main cause of death in isolated lesions of CDH
Pulmonary hypoplasia
CDH that is more difficult to diagnose
Right sided
cystic structure in chest, absence of intraabdominal stomach
Left sided CDH